Rodale's 21st-Century Herbal: A Practical Guide for Healthy Living Using Nature's Most Powerful Plants

CHAPTER 8

GROWING HERBS

People grow herbs for so many different reasons: to enjoy their beauty and fragrances in the garden . . . to harvest medicinal plants as needed . . . to have easy access to fresh culinary ingredients . . . to admire the birds and insects attracted to these plants. Whatever your intention or level of gardening knowledge, growing herbs at home can be both an enjoyable hobby and an excellent way to ensure a ready supply of fresh, sometimes hard-to-obtain plants.

Herbs blend well with other garden plants in formal and informal gardens and in containers. They are relatively care free—the chemicals they contain naturally help protect them against insect pests and plant diseases. And no matter what your growing conditions—wet or dry, sunny or shaded, dense clay or sandy loam—you’ll find dozens of species that will thrive, giving back so much for the minimal effort they require.

CHOOSING HERBS TO GROW

Besides choosing herbs for their practical purposes—for use in medicine, cooking, crafts, etc.—consider what they can add to your garden and landscape. Many herbs have colorful flowers, interesting foliage, or unusual forms.

Also consider the life cycles of the potential selections for your garden: annuals, perennials, or biennials. Annual plants die away at the end of the growing season, but new plants can be grown from the seeds borne during the preceding season. Some self-sow, producing “volunteers” that return year after year. Popular annual herbs include basil (Ocimum basilicum), chamomile (Chamaemelum nobile), coriander (Coriandrum sativum), dill (Anethum graveolens), and borage (Borago officinalis).

Perennials are plants whose upper portions die during the dormant season while their underground portions remain alive. These plants make new stems and foliage at the beginning of each growing season, and their root systems usually grow larger year after year. Common perennial herbs include bee balm (Monarda spp.), catnip (Nepeta cataria), chives (Allium schoenoprasum), lemon balm (Melissa officinalis), and echinacea (Echinacea spp.). Some herbs, such as lavender (Lavandula spp.) and rosemary (Rosmarinus officinalis), retain a woody, aboveground portion throughout the dormant months of the year. At the beginning of the growing season, new foliage forms on these older woody stems. Perennials don’t require replanting year after year, but they perform best if you give them some light annual maintenance.

Biennials have a 2-year life cycle. They grow from seed their first season; in their second season, they die after sending up flowers and making seeds. Angelica (Angelica archangelica), caraway (Carum carvi), evening primrose (Oenothera biennis), and parsley (Petroselinum crispum) are biennial herbs.

Herb gardens often contain a mix of annuals, perennials, and biennials. When planning your home herb garden, consider how you will combine these different types of herbs in a single space. Even within a mixed bed, it’s often best to segregate annuals and perennials, since their maintenance requirements can differ. (For more about garden planning and design, see Chapter 9.)

WHERE TO GROW HERBS OUTDOORS

Many gardeners choose to grow herbs in a dedicated garden space. But versatile herbs can be grown most anywhere: mixed into vegetable beds and ornamental borders, as edgings and ground-covers, in rock gardens and atop stone walls, and in indoor and outdoor containers. The ideal site for herbs depends somewhat on their purpose. You might want basil, thyme, oregano, and other culinary herbs close to your kitchen. If you want your garden to serve primarily as a contemplative retreat, the best site would be a tranquil distance away from daily human activity.

Before planting, assess the growing conditions of your potential garden space. How much sunlight does it receive? Does the sunlight vary from season to season? Is the soil naturally moist or dry? Is it heavy clay or sandy loam? Is the location protected from driving winds and rain?

Most outdoor spaces consist of several micro-climates—small areas with unique environmental characteristics such as levels of sunlight and soil moisture. Some areas of a garden might receive direct, intense sunlight all day, while others are in dappled or full shade or receive indirect, reflected light. The amount of sunlight can also vary from season to season. The area beneath a densely leaved deciduous tree, for instance, would be sunny from fall through spring but shady during summer.

Some microclimates have drier soil than others. Elevated spots have less soil moisture than low-lying areas, and plantings beneath a leafy canopy or the eaves of a house receive significantly less precipitation than those in open areas. Soil exposed to wind and sun also rapidly loses moisture. Soil composition and pH can vary widely among microclimates, too. Sandy soil drains and warms quickly, but it’s usually low in nutrients because water rapidly leaches them out. Heavy clay soil tends to contain more nutrients, but it drains poorly. As a result, plant roots grow shallowly and might not get enough oxygen, leaving plants susceptible to disease. As much as possible, match the growing conditions to the growing requirements of the herbs you want for your garden. Nearly all herbs benefit from soil that contains a good level of organic matter.

Matching herbs to a garden’s microclimate will help ensure healthy plants. Oregano plants thrive in dry, rocky conditions.

Even a garden area that receives only partial sun can be beautiful; many plants and herbs, such as this foxglove, thrive in part or full shade.

BEST HERBS for SPECIAL SITES

If you are limited to a garden site with very specific growing conditions, choose herbs that will thrive there. (Find out more about these herbs in the species entries in Part II, beginning on this page.)

PARTIAL SHADE/SHADE

Alpine strawberry (Fragaria vesca)

Angelica (Angelica archangelica)

Black cohosh (Actaea racemosa)

Black hellebore (Helleborus niger)

Bloodroot (Sanguinaria canadensis)

Blue cohosh (Caulophyllum thalictroides)

Chervil (Anthriscus cerefolium)

Epimedium (Epimedium spp.)

Foxglove (Digitalis purpurea)

Mint (Mentha spp.)

Passionflower (Passiflora incarnata)

Partridge berry (Mitchella repens)

Sweet cicely (Myrrhis odorata)

Sweet woodruff (Galium odoratum)

Tarragon (Artemisia dracunculus)

Wintergreen (Gaultheria procumbens)

DAMP/WET

Angelica (Angelica archangelica)

Bee balm (Monarda didyma only)

Elderberry (Sambucus nigra)

Elecampane (Inula helenium)

Goldenseal (Hydrastis canadensis)

Gotu kola (Centella asiatica)

Lovage (Levisticum officinale)

Mayapple (Podophyllum peltatum)

Meadowsweet (Filipendula ulmaria)

Mint (Mentha spp.)

Sweet flag (Acorus calamus)

Valerian (Valeriana officinalis)

DRY

Anise hyssop (Agastache foeniculum)

Catnip (Nepeta cataria)

Chaparral (Larrea tridentata)

Ephedra (Ephedra sinica)

Evening primrose (Oenothera biennis)

Horehound (Marrubium vulgare)

Hyssop (Hyssopus officinalis)

Marjoram (Origanum majorana)

Milk thistle (Silybum marianum)

New Jersey tea (Ceanothus americanus)

Oregano (Origanum vulgare)

Rosemary (Rosmarinus officinalis)

St. John’s wort (Hypericum perforatum)

Wood betony (Stachys officinalis)

Wormwood (Artemisia absinthium)

ALKALINE SOIL

Ashwagandha (Withania somnifera)

Bee balm (Monarda spp.)

Boswellia (Boswellia serrata)

Cowslip (Primula veris)

Goji berry (Lycium barbarum)

Lavender (Lavandula angustifolia)

Maca (Lepidium meyenii)

Rue (Ruta graveolens)

Scented geraniums (Pelargonium spp.)

Summer savory (Satureja hortensis)

ACID SOIL

Alpine strawberry (Fragaria vesca)

Bilberry (Vaccinium myrtillus)

Birch (Betula spp.)

Blueberry (Vaccinium angustifolium and others)

Blue cohosh (Caulophyllum thalictroides)

Cranberry (Vaccinium macrocarpon)

Epimedium (Epimedium spp.)

Grape (Vitis vinifera)

Horsetail (Equisetum arvense)

Mountain arnica (Arnica montana)

Partridge berry (Mitchella repens)

Sweet woodruff (Galium odoratum)

Wintergreen (Gaultheria procumbens)

Witch hazel (Hamamelis virginiana)

START WITH THE SOIL

The most important thing you can do to ensure the success of your herb garden is to care for the soil. Soil provides nutrition, water, and structural support for plants.

Most herbs prefer loose, well-drained soil that contains some organic matter, is moderately fertile, and has a pH of 6.5 to 7.0—although some herbs have other requirements. (See “Best Herbs for Special Sites.”)

If your soil hasn’t been tested recently, contact the Cooperative Extension Service to obtain a soil testing kit. A soil test conducted by a lab will give you a detailed analysis of your soil’s pH, organic matter, and nutrient content.

Soil pH can range from 4.0 or less (acidic) to 9.0 and above (alkaline); neutral soil pH is 7.0. Soil pH affects the availability of nutrients within your soil. The nutrient nitrogen, for example, is readily available in soil with a pH above 5.5. Below a pH of 6.0, the availability of phosphorous, potassium, calcium, and magnesium decreases, and the availability of the metallic micronutrients zinc, manganese, copper, and iron increases—a condition that can be harmful to plants. A very high pH, on the other hand, can result in deficiencies of these micronutrients, as well as of phosphorus. Soil microorganisms are also affected by pH; a pH of 6.6 to 7.3 is favorable for microbial activities that contribute to the availability of nitrogen, sulfur, and phosphorus in soils.

Soil pH can be raised by adding ground agricultural limestone, sold as either calcitic or dolomitic limestone—natural materials available from most garden supply stores. Calcitic limestone supplies mostly calcium; dolomitic limestone also provides magnesium. Apply limestone at the rate suggested by your soil test. Because limestone does not dissolve easily in water, it’s important to mix it thoroughly into the top 8 to 10 inches of soil.

If a soil test shows your soil to be very alkaline (a pH of 8.0 or above), add elemental sulfur to a depth of 6 inches to lower the pH. Because soil bacteria are needed to help lower pH, the soil should be moist, well aerated, and warm. Elemental sulfur works fast, but be careful not to add too much. It will work over a period of several weeks to months.

Compost is also an excellent buffer for soil pH, bringing both acid and alkaline soils closer to neutral over time, while also adding organic matter, beneficial microbes, and trace minerals.

ORGANIC FERTILIZERS MADE EASY

Plant nutrients such as nitrogen, phosphorus, and potassium are essential to plant growth, root development, and disease resistance. If a soil test indicates a deficiency of a key nutrient, such as phosphorus or potassium, add an organic fertilizer for peak performance. One of the main advantages of organic fertilizers is that they release their nutrients slowly, providing more nutrients over time. Chemical fertilizers are highly soluble and wash through your soil quickly. If your plants don’t use them, they can end up as pollutants in groundwater, and they can be harmful to earthworms and other beneficial soil organisms.

Here’s a quick overview of essential plant nutrients and the organic fertilizers that provide them.

• Nitrogen. Promotes leafy growth, but too much of it can inhibit flowering. Plants respond quickly to this nutrient, so use it sparingly. Manure, fish meal, and bloodmeal are organic sources of nitrogen.

• Phosphorus. Helps plants develop strong root systems and promotes flowering. It does not move easily in the soil, so dig it into the soil where plant roots can reach it. Organic sources include bonemeal and rock phosphate.

• Potassium. Helps plants withstand disease, drought, and temperature extremes. It also helps with fruiting and seed formation. Greensand and sulfate of potash-magnesia (a mined mineral) supply potassium.

How much fertilizer should you use? Soil test reports usually advise adding a specific number of pounds of a nutrient for every 1,000 square feet of garden soil. The label on the fertilizer will tell you the percentage of nutrients it contains. Many high-quality organic fertilizer blends are available. Apply fertilizer in small amounts when the soil is moist, and follow up with a light watering.

THE BEAUTY of COMPOST

Compost is made from plant matter that decomposes into a porous, spongy substance called humus. Indispensable to your garden, compost benefits soil and plants in so many ways.

• Helps soil retain air and moisture around plant roots, offering protection during periods of drought

• Allows water to circulate freely around plant roots, decreasing the chance of root rot

• Buffers pH and nutrient imbalances

• Protects plants from disease

• Releases a slow, steady supply of nutrients

• Darkens soil so that it warms earlier, extending your growing season

• Supports beneficial bacteria, which break down organic matter and make nutrients more available to plants

• Supports beneficial insects that help control plant pests and worms that burrow through soil to keep it well aerated.

Recycling yard and kitchen waste as compost creates fertile growing material for herbs and other plants.

THE COMPOST ADVANTAGE

There are several ways to change and improve soil quality. The very best thing you can do to improve soil structure is to add compost. Like the spongy, dark humus that covers the forest floor, compost is black gold: It is nature’s perfect recycling method for transforming organic waste, such as leaves and decaying bark, into an almost magical substance for soil and plants. Compost benefits all kinds of soils—wet, dry, sandy, heavy clay, low pH, high pH, depleted, and imbalanced.

Basil and many other herbs thrive in the loose, well-drained soil of a raised bed.

Compost can be made from yard waste, such as grass clippings, pine needles, wood chips, and leaves, as well as from straw, manure, and kitchen waste. Coffee grounds, fruit and vegetable peels, and eggshells are all excellent for composting, but avoid using meat and dairy products, which can attract insects and animals.

To make a simple compost pile, combine high-nitrogen materials (sometimes called “greens”), such as grass clippings, kitchen scraps, and manure, with carbon materials (sometimes called “browns”), such as dry leaves, wood chips, and sawdust. For best decomposition, the pile should be a minimum of 27 cubic feet (3 feet tall by 3 feet wide by 3 feet deep). Keep the materials damp but not saturated, and turn the mixture periodically with a shovel or pitchfork to admit air into the center of the pile. The more often you turn your compost, the faster it will break down. Mature compost is dark brown and sweet smelling—like humus.

Add finished compost to garden beds and containers before planting, or spread it on top of your soil as mulch.

BOOSTING RESULTS WITH RAISED BEDS

Raised beds provide ideal growing conditions for many herbs. In raised beds, soil not only drains more freely, but it also thaws and warms faster—allowing you to plant earlier in the season. The soil in raised beds also tends to remain looser and more friable because it is never walked upon.

A raised bed can be as simple as a mound of soil in any shape. But many gardeners prefer enclosed, rectangular raised beds—basically a bottomless box filled with soil. Garden suppliers sell a variety of premade enclosures for raised beds, or you can easily construct your own from wooden boards, stones, concrete blocks, or bricks.

Don’t use pressure-treated lumber, which could contain heavy metals that can leach from the wood. Chromated copper arsenate, creosote, and pentachlorophenol—chemicals used as timber preservatives—are not only toxic to insects and fungi that attack wood, but also to people, pets, and garden plants. And as attractive and “green” as recycled wood might sound, stay away from it because you won’t be able to tell whether it’s pressure treated or not. Cedar is a good choice for constructing raised beds because it is naturally resistant to rot and insect damage.

Over time, the soil can push apart the sides of wood-framed beds if the corners are not securely fastened. Building your beds with prefabricated metal corners, available from many garden supply companies, can solve this problem.

GREENING the BRONX

In the borough of the Bronx, New York City, between a brick apartment building and a lot overgrown with waist-high weeds, Victoria Cabrera cuts papalo (Porophyllum ruderale) from her urban garden plot. Papalo is a Central American culinary herb with a distinctive flavor, sometimes described as “cilantro on steroids.” It’s also used as a traditional medicine to lower blood pressure. Victoria will either use the herb in homemade tortas for her family or sell bunches of it at La Familia Verde farmers market.

Called the “Garden of Happiness,” Victoria’s garden is part of Bronx Green-Up, a community garden outreach program launched by The New York Botanical Garden (NYBG). The program began in 1988, when the NYBG donated plants to help with the cleanup of an abandoned urban lot. Through educational programs and on-site guidance, Bronx Green-Up now supports an ever-growing number of community horticulture projects, currently totaling more than 150 Bronx school and community gardens. According to a 2010 survey I conducted with Katherine Herrera of The New York Botanical Garden’s Institute of Economic Botany, 66 percent of Bronx urban gardeners grew plants for culinary purposes, 14 percent grew them for medicinal purposes, 18 percent grew them for ornamental purposes, and 1 percent grew them for ritualistic purposes.

Today, a green renaissance is sweeping New York City. Take an elevator to the top of an office building or walk over a bridge to Brooklyn, Queens, or the Bronx, and you will see green roofs; planted schoolyards, parks, and ball fields; community gardens; and even commercial farms. The contributions of urban gardeners and their rural counterparts are showing up on the menus of some of the city’s finest restaurants, which boast of the flavor and freshness of locally grown, sustainably raised food. You can even drop off food scraps at a Greenmarket—they will be composted and then used as the growing medium for a variety of crops, as well as medicinal and ornamental plants, thanks to the hard work of many urban herbal pioneers. Together, these greening efforts contribute to the sustainable management of land, economic empowerment, and improved nutrition.

If you wish to try growing papalo yourself, check the Internet for sources of seed.

—Sara Katz,

Community Horticulturist,

Bronx Green-Up at

The New York Botanical Garden

Community gardener Victoria Cabrera sells culinary and medicinal herbs, some of which are native to her home country, Honduras, at the La Familia Verde farmers’ market in the Bronx.

HOW TO START HERBS

Herb plants and seeds can be purchased from mail-order suppliers (see “Resources”) or at local plant nurseries or greenhouses. When buying plants, make sure they are robust and healthy. Always choose the bushiest plants with the most intensely colored foliage. Avoid those with pot-bound roots or pest-infested leaves.

Many plant nurseries will ship seeds, young plants, shrubs, and even trees to distant locales. Trees and shrubs purchased this way usually arrive in dormant, bareroot form. Their roots should be full and slightly moist. Plants with dry brown or soggy black roots and those with any indication that they carry insects or disease are unlikely to grow well. Don’t hesitate to return unhealthy plants for a refund.

Besides purchasing herb plants from a nursery or other retailer, you can start herbs from seeds, either directly in your garden or indoors. Herbs can also be propagated from cuttings and by division and layering.

When buying herbs at a garden center, choose bushy, multistemmed plants that are brightly colored and strongly fragrant—these are signs of good health.

GROWING HERBS FROM SEEDS

Many herbs are easy to grow from seeds sown directly in your garden, and once established, they will resow themselves freely year after year. Others have very specific germination and growing requirements.

Sowing Seeds Outdoors

Some annual herbs, such as basil, borage, and German chamomile, grow easily from seeds sown directly in the ground outdoors. Others, like caraway, chervil, cilantro, and dill, have sensitive roots, which prompt the plants to bolt—meaning go to seed—if disturbed. To grow these herbs from seeds, start them where they will grow outdoors, or sow the seeds indoors in peat pots, which later can be transplanted to the garden without disturbing the plant roots.

Perennials are generally more difficult to start from seeds, but there are some exceptions: angelica, anise hyssop, chives, fennel, lemon balm, lovage, sage, and summer savory are relatively easy to sow outdoors.

To prepare a garden bed for seeds, remove stones and clumps of soil. Dig in some compost, turn over the soil, and break it up using a hoe, rake, or similar garden tool. For optimal germination, the soil should be finely textured and lightweight. Follow the seed packet instructions for planting depth. If small seeds are planted too deep, they can run out of energy before the sprouts reach the soil surface. Some seeds require light for germination and must be pressed into the soil surface but not covered. Other seeds germinate only in the absence of light and so must be planted deeper: as deep as three or four times their width. Lightly water the seeded bed and keep the soil moist (but not saturated) until the seeds sprout.

Starting Seeds Indoors

To give plants a jump on the growing season, you can germinate seeds indoors before the weather warms and then transplant the seedlings outdoors when conditions are favorable. Seeds can be started in a variety of container types, as long as the container allows excess water to drain out of it. Commercially available “seedling trays” allow seedling roots to draw water from a bottom tray. Some, called plug trays, have thimble-sized soil “plugs” that pop out for easy transplanting.

For best results, germinate seeds in a medium specially formulated for seed starting. Seed-starting mixes are lightweight so that delicate seedling roots can grow easily, and they’re sterile, or free of pathogens, pests, and weeds. You can buy a commercial blend at a garden supply store, or prepare your own seed-starting mix at home by combining 2 parts sand, 2 parts perlite, and 1 part well-aged compost.

Moisten the medium with warm water before filling your seed-starting containers. When sowing seeds, follow the instructions on the seed packets. A general rule is that seeds should be planted no more than three to four times as deep as each seed is wide. Until the seeds germinate, keep the growing mix consistently moist—not too wet or dry—by covering the seedling trays with clear plastic wrap or a plastic dome.

Check the seed packet for the herb seeds’ ideal germination temperature; many (but not all—see “Stratification” on this page) germinate most readily in consistently warm soil. To provide gentle warmth, set your seedling trays atop a heat-generating appliance, such as a refrigerator, or on a seedling germination mat.

SEED STARTING

Starting herbs from seed is fun, easy, and thrifty. Here’s how to do it.

STEP 1: To start seeds in trays, sprinkle the seeds evenly over the surface of your moistened medium.

STEP 2: Cover the seeds with more planting medium, according to the specifics on the seed packets.

STEP 3: Gently water to moisten the surface. Cover your trays with plastic to retain moisture until the seeds sprout.

When your seeds sprout, move the trays to a spot where they will receive 14 to 16 hours of light each day. Windowsills are not usually bright enough for good seedling growth; instead, use a grow light fixture. Although many types of lights are sold and used for starting seeds and growing plants indoors (including metal halide, high pressure sodium, and LED), a standard fluorescent “shop” light fixture will work just fine for starting seeds. Keep the lights very close to the seedlings—1 to 3 inches above the leaves is optimal.

When the first true leaves appear above the seed leaves (cotyledons), it’s time to transplant the seedlings into larger containers—pressed peat pots, peat pellets, or cell packs—filled with moistened growing mix. To transplant, first make planting indentations in the growing mix of the larger containers. Use a small fork or craft stick to gently lift out the seedlings with their roots and the surrounding soil. Place the roots in the new planting holes, carefully press down the soil around them, and gently water. Feed the seedlings weekly with an organic fertilizer, such as fish emulsion that’s diluted to half-strength.

After 6 to 8 weeks, when outdoor conditions have stabilized, begin acclimating your indoor seedlings to wind, sun, and varying temperatures. This process, called “hardening off,” encourages the plants’ tender new growth to become more firm and less susceptible to damage. To do this, place seedlings in a shady outdoor location with a temperature between 45° and 50°F. Over the next few days, move the seedling containers into sunlight for increasing periods of time. After 10 days, the seedlings should be hardy enough to plant in your garden.

SEEDLINGS

After seeds sprout, it’s time to move them to a larger container.

Transplanting seedlings requires a delicate touch. Use a small fork or craft stick to gently lift them out, along with their roots.

Special Seed-Starting Techniques

A few herbs require special but very simple seed-starting methods.

Scarification: Scarification simply means “scarring” or nicking the seed coat. It is used to promote the germination of hard seeds, such as those of astragalus. To scarify seeds, use a sharp knife to gently nick the outside of the seed, or rub seeds over a piece of fine sandpaper. Small seeds can be rubbed between two pieces of fine sandpaper.

Stratification: This is a method of chilling seeds to encourage germination, just as the seeds of many plants in nature require a period of chilling before they can germinate—breaking their dormancy by going through cold winter temperatures. Echinacea (Echinacea spp.), gentian (Gentiana lutea), jewelweed (Impatiens capensis), lavender (Lavandula angustifolia), myrrh (Myrrhis odorata), osha (Ligusticum porteri), and sage (Salvia officinalis) seeds respond well to stratification. Put seed packets in a zipper-lock bag (to keep them from drying out), mark the date on the bag, then refrigerate the sealed bag for 4 to 6 weeks, or the recommended period for your specific seeds. Start seeds according to the packet directions.

THE BEST METHODS for STARTING PLANTS

Your very first garden herbs no doubt will be young plants started by a local or mail-order nursery. But within a year or two, you’ll find that starting your own herbs is a fun and inexpensive way to fill your garden with old favorites and new varieties. Use the following methods for starting specific herbs.

HERBS TO START FROM SEED

Angelica (Angelica archangelica)

Anise (Pimpinella anisum)

Anise hyssop (Agastache foeniculum)

Basil (Ocimum basilicum)

Borage (Borago officinalis)

Calendula (Calendula officinalis)

Caraway (Carum carvi)

Chervil (Anthriscus cerefolium)

Chile peppers (Capsicum annuum)

Chives (Allium schoenoprasum)

Cilantro (Coriandrum sativum)

Dill (Anethum graveolens)

Fennel (Foeniculum vulgare)

Hyssop (Hyssopus officinalis)

Lemon balm (Melissa officinalis)

Lovage (Levisticum officinale)

Marjoram (Origanum majorana)

Oregano (Origanum vulgare)

Rosemary (Rosmarinus officinalis)

Sage (Salvia officinalis)

Salad burnet (Sanguisorba minor)

Summer savory (Satureja hortensis)

Thyme (Thymus vulgaris)

Valerian (Valeriana officinalis)

HERBS TO START FROM CUTTINGS

Basil (Ocimum basilicum)

Catnip (Nepeta cataria)

Lavender (Lavandula angustifolia)

Mint (Mentha spp.)

Oregano (Origanum vulgare)

Pineapple sage (Salvia elegans)

Rosemary (Rosmarinus officinalis)

Sage (Salvia officinalis)

Thyme (Thymus vulgaris)

HERBS TO GROW FROM LAYERING

Creeping thyme (Thymus serpyllum cv. ‘Coccineus’)

Lavender (Lavandula angustifolia)

Lemon balm (Melissa officinalis)

Marjoram (Origanum majorana)

Mint (Mentha spp.)

Oregano (Origanum vulgare)

Roman chamomile (Chamaemelum nobile)

Rosemary, prostrate (Rosmarinus officinalis var. prostratus)

Sage (Salvia officinalis)

Tarragon (Artemisia dracunculus)

Thyme (Thymus vulgaris)

Winter savory (Satureja montana)

HERBS TO START FROM DIVISION

Bee balm (Monarda spp.)

Catnip (Nepeta cataria)

Chives (Allium schoenoprasum)

Germander (Teucrium chamaedrys)

Hyssop (Hyssopus officinalis)

Lemon balm (Melissa officinalis)

Lemongrass (Cymbopogon citratus)

Mint (Mentha spp.)

Oregano (Origanum vulgare)

Rue (Ruta graveolens)

Saffron (Crocus sativus)

Sweet woodruff (Galium odoratum)

Tarragon (Artemisia dracunculus)

GROWING HERBS FROM CUTTINGS

If you or a friend already has mature herb plants, you might be able to start new plants quickly and easily by taking cuttings and then rooting them in water or a growing medium. See the chart for suggested herbs to start from cuttings.

Rooting Cuttings in Water

Cuttings of basil, mint, and pineapple sage root quickly in water. The best time to take the cuttings is early in the growing season, when your plants have just begun to produce new growth. Use scissors or pruning shears to clip pieces of stem that are about 6 inches long and have several leaf nodes. Clip just below a node. Place the cuttings in a clean, water-filled glass container, and set it in a sunny window. Remember to change the water daily. Roots should soon form along the lower portion of the cutting. When the roots are about ¼ inch long, plant the new herbs in potting soil or directly in your garden. (Follow the instructions for “hardening off” seedlings before transplanting the rooted cuttings to your garden.)

Rooting Cuttings in a Growing Medium

Stem cuttings of basil, catnip, lavender, oregano, rosemary, sage, and thyme can be rooted directly in a growing medium, such as a combination of peat moss and sand, or a store-bought mixture. Use sharp scissors or pruners to take 6-inch stem cuttings that have several leaf nodes. Strip the bottom two-thirds of the leaves from the cuttings, then dip them into a rooting hormone solution. Stick the cut ends about 3 inches deep in a pot filled with premoistened growing medium; space the cuttings about 4 inches apart. Provide indirect light and keep the medium consistently moist.

To encourage rooting, maintain a humid environment by loosely covering the cuttings with clear plastic until they form roots—about 4 to 6 weeks. Occasionally lift an edge of the plastic to mist the plants with water. When the cuttings begin to grow new leaves, transplant them to individual containers filled with regular potting soil, or to your garden. (Follow the instructions for “hardening off” seedlings before transplanting the rooted cuttings to the garden.)

ROOTING CUTTINGS IN A MEDIUM

STEP 1: Take 6-inch cuttings that have several leaf nodes.

STEP 2: Strip the bottom 4 inches of leaves, then dip the cutting in a rooting solution.

STEP 3: Sink the bottom 3 inches into a premoistened medium; maintain a humid environment until cuttings form roots.

GROWING HERBS FROM DIVISIONS

Another easy way to multiply herbs is to divide large, established plants. Three types of herbs can be propagated by division: (1) herbs that form bulbs, cloves, or corms (such as chives and saffron); (2) herbs that creep (such as mint, oregano, and sweet woodruff); and (3) herbs that form clumps (such as germander, catnip, and lemon balm). At the beginning of the growing season (for peak- or end-of-season bloomers) or at the end of the growing season (for early season bloomers), use a garden fork to carefully dig up an entire plant. Gently separate the roots into smaller sections. Each new, small plant should contain a good set of roots and some strong, healthy shoots. Replant these immediately, or store bulbs, corms, or tubers in a cool, dry spot for planting later.

DIVIDING

Herbs that creep, clump, or form bulbs are easy to multiply by division.

STEP 1: To start new chive plants, use a garden fork to lift the roots of a 3- to 4-year-old plant.

STEP 2: Carefully separate the plant into smaller sections, each with healthy roots and shoots.

STEP 3: Replant the divisions immediately, then water well.

GROWING HERBS BY LAYERING

When the stems of some herbs (especially mint, thyme, and oregano) touch the soil, the plant might sprout roots at the point of contact. When this occurs naturally in your garden, the new plantlets can be separated from the main plant, dug up, and relocated. You can use this same process, called layering, to propagate lavender, lemon balm, prostrate rosemary, Roman chamomile, sage, tarragon, and winter savory.

LAYERING

Plants that sprawl or creep, such as mint or oregano, are easy to propagate by layering.

STEP 1: To layer a low, creeping herb such as mint, choose a long, flexible stem low to the ground. Starting 3 to 4 inches from the tip, remove the leaves from a section that is a few inches long.

STEP 2: Use a pair of sharp scissors to gently scrape the outside layer from that section of stem. This will encourage the stem to make roots at that point.

STEP 3: Carefully bend the stem to the ground and cover the scraped section with soil. Anchor it in place with a small rock, then water thoroughly.

STEP 4: Keep the area moist until roots grow–usually within 4 to 6 weeks. The following spring, clip the “mother stem” and dig up a new plant. Transplant it to its new garden location.

PLANTING HERBS

Whether you are starting herbs from seeds, cuttings, or division, or purchasing plants from a garden center or mail-order supplier, your plants will grow best if they’re properly planted. This is especially important for shrubs and trees, which are usually a larger financial investment than annuals and perennials.

TRANSPLANTING

Ease young herbs’ transition to the garden to avoid any setback in their growth.

STEP 1: To transplant herbs such as basil, dig a hole deeper and wider than the size of the seedling’s container.

STEP 2: After removing the plant from its container, place it in the hole so that the tops of the roots are level with the soil surface.

STEP 3: Fill in the hole, cover the roots with soil, pressing down firmly to eliminate any air pockets.

STEP 4: Water well, so that the soil is soaked, ensuring that the roots receive enough water to encourage new growth.

PLANTING SEEDLINGS

Plant annuals, such as basil, in your garden after the last expected spring frost date; perennials can be planted 1 or 2 weeks earlier. If possible, plant on an overcast day or during the late afternoon or evening, when sunlight is less intense, to reduce stress on your plants. Water annuals and perennials several hours before you transplant them. Also soak the roots of bareroot plants for an hour or two prior to transplanting.

Prepare the site before planting by mixing compost, limestone, and other necessary amendments uniformly throughout the soil. To plant seedlings of annuals and perennials, dig a hole slightly deeper and wider than the container. Next, remove the plants by inverting their containers and gently pushing from the bottom. If the roots have become compacted within the pot, use the tip of a trowel to make shallow vertical cuts into the outside of the rootball. This will encourage new root growth into the surrounding soil after planting. Avoid holding seedlings by their tender stems or leaves, which can put unnecessary stress on these fragile plant parts. Instead, grasp the root ball.

Set the plants into the holes so the tops of the roots are level with the ground. Cover the roots with soil, pressing down firmly to eliminate any air pockets around the roots. Water the plants immediately. When working with plants grown in peat pots or peat pellets, place the entire container directly into the ground—the plant’s roots will grow right through the walls of the pot, which will disintegrate. Be sure to cover the tops of peat pots completely, or tear off their top lips. An edge sticking out of the soil can act as a wick, drawing water away from the plant’s roots.

To help plants recover from the shock of being transplanted, soak them well and then shelter them from wind and sun for a few days by covering them with a flowerpot, basket, or small tree branch with leaves. If rainfall is insufficient the first week after transplanting, water the plants daily. During the second week after transplanting, water the plants every other day, and then every third day the third week. Steady watering is especially important for seedlings because their roots haven’t developed enough to reach deep soil moisture.

PLANTING SHRUBS AND TREES

Shrubs and trees are sold in one of three forms: balled-and-burlapped (also called B&B), containerized, or bareroot. Most mail-order nurseries ship deciduous trees, bushes, and roses in bareroot form, wrapped in sphagnum moss, to reduce shipping charges. When bareroot plants arrive by mail, unpack them as soon as possible and soak the roots in water for several hours.

Plant shrubs and trees as soon as possible after you receive them in the mail or buy them at a nursery. If immediate planting isn’t possible, hold the plants temporarily in a shady spot; cover bare roots with moist soil, sand, or peat moss. Moisten the soil of B&B or containerized plants that you are unable to plant immediately.

The best time to plant shrubs and trees is at the end or the very beginning of the growing season, when they are most likely to generate new roots and least likely to lose moisture through their leaves. The bareroot stock shipped by mail-order nurseries is usually dormant (without leaves), and could be small in size. Smaller shrubs and trees are usually more economical than larger plants. They also adapt more quickly to their surroundings, are less likely to suffer transplant shock, and quickly catch up to larger plants.

Before planting, be sure to site shrubs and trees far enough from foundations and paths so that, when fully grown, these plants will not block windows, crowd or damage buildings, or interfere with foot traffic. Once you’ve chosen your spot, dig a hole twice as wide but only as deep as the plant’s roots (or its pot).

CONTAINING INVASIVE HERBS

Certain herbs grow so enthusiastically that they can take over a garden if not monitored. Mint, which sends out rhizomes below the surface of the soil, can sneak through a garden and choke out other plants. Horseradish, sweet woodruff, and tarragon can spread similarly. Prolific seeders such as borage, catnip, lemon balm, and mugwort generously spread their offspring all around a garden.

To keep creeping herbs such as mint under control, plant them in containers sunk into the soil, but leave a bit of the containers’ rims above the ground. Pull up a pot periodically and check to make sure the roots of the plant have not escaped through a drainage hole. If they have, pull the roots gently out of the soil, getting as much of them as possible, and remove them from the bottom of the pot. Aboveground, you may have to remove plants as they spread out of the pot and begin to colonize the surrounding area. In addition, to help reduce the spread of borage, catnip, lemon balm, and other prolific seeders, remove their flower heads before they go to seed.

For potted and bareroot plants: If the plant is in a container, ease it out and then use clean, sharp pruning shears to remove any damaged or diseased roots. Place the roots or rootball in the hole. When planted, the top of the roots or rootball should be level or slightly above the surface of the surrounding ground.

For B&B plants: Pull the burlap off of the root-ball, leaving it in the hole. If the rootball is enclosed in a wire basket, cut the wires so they are below the surface of the soil and will not interfere with raking or cultivation.

Fill the hole three-quarters full with soil. Make sure the plant is standing up straight, and then gently press down the soil around it. Add water to eliminate any air pockets, and then fill the hole to ground level. Use additional soil to build a ring, or berm, about 6 inches from the outside edge of the hole. Water heavily again.

Finally, add a 2- or 3-inch layer of organic mulch, such as bark chips or shredded leaves, around the base of the plant to reduce moisture loss and discourage weed growth. Do not let the mulch come in direct contact with the trunk, however; this can damage the bark and encourage insect and disease troubles. In addition, a big pyramid of mulch around a tree can limit gas exchange in the soil, cutting off its supply of air and harming its growth. (For more, see “The Magic of Mulch.”)

During the first growing season, water shrubs and trees once a week if there is no rain, slowly soaking the soil. The water should reach the top of the berm so it will penetrate deeply and encourage root development. Watering is particularly crucial for B&B and container-grown shrubs and trees. In the nursery, the roots of these plants become concentrated in a small cluster. Until the roots are able to spread into the surrounding soil, these plants draw water mostly from their rootballs, which will dry out more quickly than the soil around them.

HERB GARDEN MAINTENANCE

Maintaining a healthy, vibrant garden of any kind means paying attention to the water and nutrient needs of your plants; managing competing weeds; and preventing or stopping disease and insect problems before they get out of hand. Fortunately, herbs are among the easiest plants to grow—typically, they need much less maintenance than other garden plants. By following these basic tips and techniques, your herb garden will practically care for itself.

WATER WISELY

In most areas, rainfall provides adequate moisture for herbs. Covering the surface of your garden beds with a 1- to 3-inch layer of organic mulch (such as shredded bark, leaves, or compost) will help retain soil moisture, suppress weeds, and prevent soil erosion. Water is essential to plant growth. When rainfall isn’t enough, deep watering once or twice a week can help.

If an extended drought causes some plants to wilt, deep watering (permeating 1 to 3 inches below the surface) can help them recover. Deep watering ensures healthier root development than shallow daily watering, which simply encourages the growth of roots upward toward the bit of moisture that is being provided. Before watering, loosen the soil that surrounds the plants to encourage easier absorption and discourage runoff. Water in the morning, if possible, so that any droplets that splash onto foliage can evaporate during the day. Using a soaker hose or drip irrigation will also keep foliage dry, protecting your plants from diseases (such as fungal infection) promoted by dampness. By releasing water close to the root zones of plants, drip systems also foster deep root growth and minimize runoff and evaporation.

Soaker hoses deliver water efficiently to plant roots; less moisture is lost to evaporation.

A HEALTHY DIET

For most herbs, a yearly application of compost is enough to keep their soil in good condition. But some herbs—especially fast-growing annuals such as basil, cilantro, and dill—benefit from an occasional boost of organic fertilizer, such as fish emulsion or liquid seaweed. Avoid feeding plants too much nitrogen (such as in manure) because it can encourage weak growth that’s more susceptible to disease and the ravages of cold weather.

Once or twice a month, from spring to midsummer, treat your herbs to some compost “tea”—an effective liquid fertilizer and preventive for some mildew diseases. To make compost tea, place 1 quart of finished compost in a 5-gallon bucket, and then fill the bucket halfway with water. Steep the mixture for 5 to 15 days, then strain out the compost. Reserve the liquid and dilute it until it is the color of a cup of black tea. Spray the liquid on plant leaves early in the morning, or apply it to the soil around fast-growing herbs.

Routine garden maintenance—weeding, pruning, and watering—keeps an herb garden healthy and beautiful.

THE MAGIC OF MULCH

Mulch—a thin layer of organic or inorganic matter laid on the soil’s surface—helps keep soil cool during the growing season and provides insulation during the dormant months. Mulch also slowly releases nutrients into the soil, retains moisture, and suppresses the growth of weeds around plantings.

The best organic mulches for garden plantings are shredded leaves, pine needles, and compost. Compost provides the added benefit of protecting plants against diseases. Studies at Ohio State University showed that a 2-inch layer of compost mulch blocked weeds while greatly enhancing plant growth. High-carbon materials, such as wood chips and sawdust, can inhibit plant growth in the garden, but they’re perfect for mulching pathways. A double-layered mulch of damp newspapers topped with chipped bark or gravel works even better for stopping pathway weeds.

Apply a 2- to 4-inch layer of mulch over garden beds, but keep it several inches away from plant stems and trunks so that it doesn’t damage the bark and encourage insects and disease. Replenish organic mulches every few years.

If mulch isn’t enough to stop the growth of aggressive, unwanted plants, use a trowel or shovel to carefully remove these plant by their roots. Continue to inspect the area because new plants can sprout from root fragments or seeds.

PROPER PRUNING

Proper pruning encourages plants to produce healthier, bushier growth. Follow these guidelines to keep your herbs growing strong for years to come:

• In midspring to late spring, prune woody, aromatic herbs such as lavender, sage, southern-wood, and rosemary. Use clean, sharp gardening shears to remove older, leggy growth. This will prompt the plant to generate young, healthy stems.

• In early summer, prune flowering stems to promote extended foliage production of such herbs as basil, Roman chamomile, chervil, costmary, lemon verbena, oregano, and tarragon. The flowering stems of these herbs will divert the plants’ energy from the formation of fragrant or flavorful foliage. To prevent or delay flowering, use gardening shears to cut the flower stems at their bases. For tender herbs such as basil, pinch off flowers as they form to prolong the production of aromatic foliage.

• In the middle of the growing season, after they have flowered, cut back catnip, comfrey, lemon balm, marjoram, mint, sweet cicely, and salad burnet. These herbs produce less-flavorful and tougher foliage later in the season. Cut the plants back by one-third to one-half to encourage a burst of tender new foliage.

Planting in a protected area, such as next to a fence or building, can help herbs at the limit of their cold-tolerance survive winter. Mulch, row covers, and cold frames also offer protection against cold.

EXTENDING THE GROWING SEASON

For annuals and tender-leaved perennials in temperate regions, the first and last frosts of the year generally signal the beginning and the end of the growing season. Neither annuals nor tender perennials tolerate temperatures below freezing: A night of frost can turn a healthy plant into a cluster of blackened, shriveled sticks. On the other end of the spectrum, plants accustomed to cool weather can fail to germinate under a blistering sun.

Sheltering structures can help moderate soil and air temperatures below and around plants, protecting individual plants or whole beds. In hot areas, a shade net of woven polypropylene fabric stretched over wire hoops or a movable wooden frame can keep soil cool and moist. Shade netting can be placed over newly sown seedbeds and transplanted seedlings to shield them from drying winds and to buffer the intense heat and light of the sun.

In cool weather regions, a cold frame can be used to trap the sun’s heat and begin the growing season a few weeks earlier in spring and extend it a few weeks later in fall. A cold frame is a low, bottomless, boxlike structure that acts like a greenhouse. It usually has a higher south-facing back wall, a white interior to reflect light throughout the box, a glass or clear plastic cover that allows the sun’s rays to penetrate, and a thermometer to monitor the interior temperature. You open the cover to reduce the temperature when it climbs too high for the plants inside. Cold frames are good for starting seedlings in spring, for hardening off seedlings that have been started indoors, and for extending the harvest season of cold-sensitive plants. A cloche or a bell-shaped cover (made from such materials as a plastic milk jug) can also be used to protect individual plants from cold temperatures in spring and fall.

In all climates, strong winds can prevent herbs from developing sturdy root systems, thereby preventing healthy growth. A wooden fence or row of planted shrubs can act as an effective windbreak, providing enough shelter to allow some marginal plants to survive otherwise.

GROWING HERBS IN CONTAINERS

Pots, planters, and half barrels overflowing with colorful and flavorful herbs add appeal to any garden or home. Growing herbs in containers can serve a variety of practical purposes, as well. If you live in the city and have limited growing space, containers of herbs can turn your balcony into a productive garden. If your yard is shaded, you can locate containers in sunny areas more conducive to plant growth. If you want to grow herbs right outside your kitchen door but your garden is many steps away, containers can solve that problem, too.

Container-grown plants also add versatility to gardens large and small. A pair of matching containers on either side of the front walk can serve as a welcoming decoration, while groups of pots on a deck can provide privacy as well as color, fragrance, and texture. You can position containers on the ground or on a pedestal, mount them on a windowsill, or hang them from your porch. Plant them with a single species, such as rosemary, bay, or thyme, for a stunning garden accent, or experiment by combining herbs of different forms and colors. The possibilities are almost endless.

CHOOSING CONTAINERS

Pots and planters are available in a wide range of sizes, shapes, materials, and styles. You can also modify containers such as bowls, barrels, buckets, wheelbarrows, and wagons to be planters. It’s worth investing in attractive, well-made planters, even if they cost a little more. They will add beauty to your garden’s decor, while inferior planters could detract from it, no matter how appealing the plants they contain.

For the growth and even survival of most plants, bigger pots are better. Those 10-inch hanging baskets—the ones so popular at garden centers in spring—require constant watering in summer. If you go away for the weekend, you’re likely to find a shriveled plant upon your return. But with a larger container and more soil, your herbs can grow a larger root mass that will support lush, healthy, aboveground growth. Larger pots also retain soil moisture longer and are better insulated against temperature fluctuations.

To determine how large and deep a container should be, consider the size and shape of the herbs you wish to grow, as well as the plant types—annuals, perennials, or shrubs—and how rapidly they will grow. Rootbound plants dry out rapidly and won’t grow well. For a mixed planting, choose a planter with enough root space for all of the plants you want to grow.

The maximum size (and weight) of a container will be limited by how much room you have, whether or not you plan to move the container, and the strength of the supporting structure. If your container garden is located on a balcony or deck, be sure to check how much weight the structure will safely hold. If you aren’t sure, contact a structural engineer for an opinion. Remember that a fully watered large clay pot with plants can easily weigh 50 pounds or more.

Whatever container you choose, drainage holes are essential. Without drainage, the soil will become waterlogged, and your plants could die. The holes need not be large, but there should be enough of them to allow excess water to drain out. If a container has no holes, try drilling some yourself (if the container can be drilled). A container without holes is best used as a cachepot, or cover,

Potted herbs can lend instant color, provide a focal point, or help link the architecture of your house to your garden. to hide a plain pot.

Cachepots (with holes or without them) are useful for managing large plants and heavy pots: Grow your plant in an ordinary nursery pot that fits inside a decorative cachepot so you can move them separately. Self-watering double-walled containers, hanging baskets, and window boxes are also available. These are useful for dealing with smaller plants that need frequent watering.

Containers are made from a variety of materials, and each type has advantages and disadvantages concerning their durability, appearance, weight, and initial cost.

• Clay or terra-cotta containers are attractive but breakable and are easily damaged by freezing and thawing. In northern areas, store these pots in a frost-free location to prevent cracking. They are not suitable for hardy perennials or hardy shrubs kept outdoors year-round.

• Cast concrete is long lasting and comes in a range of sizes and styles. These can be left outside in all weather and temperatures. You can even make attractive ones yourself. Plain concrete containers are very heavy, so they’re difficult to move and not suitable for use on decks or balconies.

• Stone planters provide both durability and beauty, and they come in many different colors and textures. These containers require little maintenance but are very heavy and best used on firm ground.

• Plastic, resin, and fiberglass planters are lightweight, relatively inexpensive, and available in many sizes and shapes. Choose sturdy and somewhat flexible containers and avoid thin, stiff ones—they become brittle with cold or age.

• Wood is natural looking and protects roots from rapid temperature swings. You can build wooden planters yourself. Choose a naturally rot-resistant wood such as cedar, and never use wood treated with a preservative, which could leach into your soil, enter the roots of your herbs, and ultimately end up in your body. If you’re purchasing a premade container, be sure it was made with untreated wood.

• Metal containers are strong, but they conduct heat, exposing roots to rapid temperature fluctuations. Also, metal must be lined with plastic if you’re growing edibles.

• Hayrack planters with coir liners are attractive and easy to maintain, and they provide good drainage. They’re great for annuals but not usable for perennials.

Porous terra-cotta pots allow air and moisture to penetrate. This means plants are less likely to drown if overwatered, but they could suffer if you forget to water.

PREPARING CONTAINERS FOR PLANTING

Before you fill and plant your containers, decide where they will be located and move them there. If you plan to move heavy or large pots indoors in fall or to follow the sun during the day, platforms with wheels are available. If you’ll have difficulty watering daily, look for sites that receive morning sun and are shaded during the hottest part of the day, even if you are growing plants that like full sun. Afternoon shade will reduce the amount of moisture your plants need.

Your containers must have drainage holes. If a pot is too deep for a very shallow-rooted plant, you can put a layer of gravel or lightweight packing peanuts in the bottom to reduce the amount of potting soil required.

Plain garden soil is usually too heavy for container plantings. For growing herbs in containers, use a commercial soil mix for houseplants, or make your own lightweight mix. (See the following potting mix recipes.)

Many of the components of potting soil are lightweight, dust-producing materials that can irritate your eyes, skin, and lungs. In some cases, vermiculite—which is in certain soil mixes—has been found to contain low levels of asbestos, and compost and peat moss can contain mold spores. Therefore, when you work with potting soil, observe the following precautions:

• Work outdoors or in a well-ventilated garage or garden shed.

• Wear a dust mask and gloves.

• Dampen individual ingredients before mixing them together to minimize the amount of dust released.

• After combining the ingredients, add more water to the mix, then stir to ensure that the medium is evenly moist before you fill the containers. After potting, store any leftover mix in a plastic bucket with a lid.

• If you’ve been working with vermiculite, be aware that the dust can cling to your clothing. Remove and wash dusty clothing as soon as possible to avoid dispersing asbestos inside your house.

Organic Potting Mix

This simple potting mix provides good drainage, air, and nutrients for growing plant roots.

1 part garden soil

1 part well-aged compost

1 part coarse sand or shredded pine or fir bark

1 part perlite (optional)

Enriched Potting Mix

Slow-growing plants, which will remain in the same container for several years, benefit from a mix that contains slow-release organic fertilizers.

1 cubic foot (approximately 32 quarts) Organic Potting Mix (above)

3 ounces bloodmeal

3 ounces soft rock phosphate or colloidal phosphate

3 ounces greensand

2 ounces dolomitic limestone (optional for alkaline-loving plants)

SELECTING PLANTS

Almost any herb—including shrubs and small trees—can grow successfully in a container. Dwarf and compact cultivars are best, especially for smaller pots. Select plants to suit the amount of sun or shade the container will receive.

Use your artistic imagination, and combine upright and trailing plants, colorful foliage, and flowers for pleasure and delight. Grow your favorite combinations of culinary herbs. A “pizza garden” might contain individual plants of thyme, oregano, and basil. A “chili garden” might have several colorful cultivars of hot chile peppers. Container gardens can be enjoyed for one season and composted, to be replanted at the beginning of the next growing season, or they can be designed to last for years.

When designing permanent containers, remember that container plants will be less hardy than usual because their roots are more exposed to fluctuating air temperatures. Nonhardy plants will need outdoor protection or indoor shelter in winter, so consider how heavy the container will be and how you will move it before you plant.

Plant in containers as you would in your garden. If you are planting a mixed container, ignore spacing requirements and plant densely; you’ll need to prune plants once they fill in. Depending on the size of the herb and its type—leafy or with very small leaves; tall or short; spreading or upright; annual, perennial, or shrub—you might need as many as four plants for an 18- or 24-inch container. For trees and shrubs, trim off any circling roots and cover the rootball to the same level as it was set at the nursery. Firm the planting medium gently, and settle it by watering thoroughly. Don’t fill pots all the way to the top with your soil mixture—leave space for watering. And, if you are gardening a few stories up in the air, remember that water follows the rules of gravity.

GROWING HERBS INDOORS

Containers are a must if you wish to grow perennial and woody herbs native to tropical or subtropical regions in a temperate climate, such as throughout most of North America. Such herbs as galangal, pineapple, and vanilla must be grown either indoors in a sunroom or warm greenhouse year-round or in a container that can be moved indoors when temperatures fall below 40° to 60°F, depending on the plant.

Before moving potted herbs indoors, inspect them carefully for insects (or treat them with insecticidal soap as a precaution). Check the plant entries in Part II of this book (beginning on this page) for more details on individual light, temperature, and moisture requirements. In spring, before moving your plants outdoors, check your pot sizes and root prune or repot if necessary. Acclimate plants gradually to outdoor conditions the same way you would harden off seedlings (see this page).

Here are just a few tropical and subtropical herbs that can be grown in containers year-round in a warm greenhouse or grown outdoors and moved indoors when temperatures cool.

Allspice (Pimenta dioica)

Aloe (Aloe vera)

Annatto (Bixa orellana)

Black pepper (Piper nigrum)

Cinnamon (Cinnamomum cassia and C. verum)

Coffee (Coffea arabica)

Galangal (Alpinia galanga)

Ginger (Zingiber officinale)

Gotu kola (Centella asiatica)

Guarana (Paullinia cupana)

Kava (Piper methysticum)

Lemongrass (Cymbopogon citratus)

Maté (Ilex paraguariensis)

Patchouli (Pogostemon cablin)

Pineapple (Ananas comosus)

Stevia (Stevia rebaudiana)

Tea (Camellia sinensis)

Turmeric (Curcuma longa)

Ylang-ylang (Cananga odorata)

CARING FOR CONTAINER PLANTS

Water container plants thoroughly. How often you water depends on many factors, such as weather, plant size, and pot size. Don’t let soil in containers dry out completely, as it is hard to rewet. To keep large containers attractive, spread a layer of mulch as you would in your garden. This will also help retain moisture. Be sure to keep mulch an inch or so away from plant stems and a few inches below the rim of the container.

Container plants need regular feeding, as the limited soil that nurtures the plant also has a limited supply of nutrients. Fertilize plants by watering them with diluted fish emulsion, seaweed extract, or compost tea. Start by feeding once every 2 weeks; adjust the frequency depending on plant response. Be careful not to pour fertilizer directly over the edible leaves of plants you harvest frequently, such as basil. (There’s no need to dress your salad with fertilizer!)

Since containers are focal points outdoors and indoors, give them special attention to keep them looking their best. Remove tattered leaves and deadhead spent flowers. Prune back leggy plants and those that stop blooming. To keep mixed plantings attractive, dig out or cut back any plants that don’t grow well or that go to war with other species, crowding them out aboveground or below-ground. Also keep an eye out for pests such as aphids and mites, and deal with them as soon as possible.

The damage caused by snails and slugs is obvious—holes that cause significant harm to leaves and impede overall plant growth. One way to control snails and slugs is to trap them with a shallow saucer of beer.

ROOT PRUNING

Root pruning rejuvenates pot-bound plants. Do this every 2 to 3 years for most potted plants; more aggressive growers (such as mints) may require annual root pruning.

STEP 1: To prune the roots of herbs such as mint, first gently remove the plant from its container.

STEP 2: Using a serrated knife, cut each corner from the root base. Do not cut too close to the herb’s main stem.

STEP 3: Use a pair of sharp scissors to neaten any straggling roots. Do not cut too deeply into the rootball.

STEP 4: Return the herb to the pot. Snip off older, leggy stems above the soil to encourage new, healthy growth.

HARVESTING HERBS

Herbs can be harvested throughout the growing season—and even throughout the dormant season, if grown indoors. The following tools are useful to have on hand at harvesttime: pruning shears (remember that sharp shears are less likely to injure plants or you), rubber bands or twine (for tying bunches of stems together), and, on very hot days, a bucket of cool water in which to immerse herb stems.

If you’re harvesting seed heads, bring along small paper bags to contain them. To harvest roots, you’ll need a garden trowel or hand fork.

WHEN TO HARVEST

Small amounts of herbs can be harvested for immediate use throughout the growing season. Major harvests, however, should occur a few days before each plant flowers, when the concentration of essential oils in the leaves is highest. Flowering time varies among herbs, so observe your plants carefully. Perennials should not be pruned or harvested heavily during the last 30 to 45 days of your growing season, before your first seasonal frost is expected; this will ensure that your plants are strong enough to survive the dormant season. You can harvest annuals, such as basil, right up until they are killed by frost; after that, pull entire plants and compost them.

When harvesting a large amount of herbs for drying, making vinegars and potpourris, or other purposes, try to work during the cooler times of the day, when the herbs’ essential oils are unlikely to evaporate and their foliage is less likely to wilt. The best time to harvest herbs is just after the morning dew has completely dried, because this moisture can cause the herbs to mold—making them useless for any kind of preparation.

HARVESTING LEAVES

It’s important to remove herb leaves and stems in a way that will help promote new growth, rather than harming the plant. The method for doing that varies from herb to herb. Fortunately for the home gardener, most common herbs fall into just two of the more than 300 identified plant families, so it is relatively simple to learn the preferences of these two families.

• Herbs in the mint (Lamiaceae) family, including basil, bee balm, hyssop, lavender, lemon balm, marjoram, mint, oregano, and rosemary: Cut in the middle of their stems, just above a set of leaves, or pinch off the growing tips from the ends of the stems. Two new stems will form at these junctures, promoting abundant, bushy growth. Members of the mint family will produce vigorous new growth when cut back by one-third between the time they flower and set seeds, increasing their yield substantially. Tarragon and lemon verbena have growth habits similar to mint; harvest them the same way.

• Plants in the parsley (Apiaceae) family, including angelica, caraway, dill, fennel, parsley, and sweet cicely: Harvest by cutting stems at their bases from around the outside of the plant. This will encourage new shoots to grow from the center. Annuals in the parsley group (such as cilantro) produce leaves for a brief time before they flower. Harvest these leaves three to six times during the period before flowering.

Other types of herbs can be harvested and pruned using methods suggested by their growth habits. Chives, for example, sprout a dense cluster of blades from their bulbs. Cut individual chive blades close to the ground, or cut the entire plant to 1 inch above the soil level. New blades will generate from the bulbs. Bay (Laurus nobilis) and scented geranium both sprout leaves along their stems. Harvest these leaves individually. For herbs that produce both usable leaves and flowers, such as yarrow, feverfew, and tansy, wait to harvest the entire stem until just before the blooms open.

Another way to collect mature seeds is to tie muslin bags over the seed heads of plants as they grow; the bags will catch seeds as they drop naturally. If the seeds haven’t dried naturally on the plant, spread them out on paper towels and allow them to finish drying, Store dry, harvested seeds in a cool, dry place in cardboard boxes or in twists of aluminum foil.

HARVESTING SEEDS

Gather seeds when they are ripe. On most plants (including caraway, coriander, dill, and fennel), the seed color changes from green to tan to light brown as ripening occurs. To harvest seeds, pull up the whole plant from the soil when the seeds are barely ripe. Hang the plant upside down with a paper bag tied over the seed heads; as the seeds ripen and dry, they will drop into the bag.

HARVESTING

Proper harvesting techniques will help keep your herbs growing strong.

To harvest the leaves of herbs, including mint, cut the plant in the middle of its stem, just above a set of leaves.

HARVESTING FLOWERS

Herb flowers, such as those of calendula, lavender, and yarrow, should be picked just before they fully open. The flowers are more likely to lose their petals if you harvest them after they are completely open. But if you cut them before they are fully open, they will continue to open in the vase. Harvest flowers early in the day and transfer the stems to a vase or glass of water until you’re ready to use them.

HARVESTING ROOTS

Most roots—including those of astragalus (Astragalus membranaceus), burdock (Arctium lappa), dong quai (Angelica sinensis), and echinacea (Echinacea spp.)—should be dug and harvested from mature plants at the end of the growing season, after a plant’s leaves have yellowed and begun to die back. The roots of horseradish (Armoracia rusticana) are best dug when they are younger, before their flavor becomes too strong and their texture too coarse. Harvest roots using a garden fork: Carefully lift the root, then cut it away from the rest of the plant. Rinse roots with water, blot them dry, and then store them in a dry, well-ventilated area.

CLEANING HERBS

Plants that grow on long stems—basil, cilantro, and chives, for instance—are usually fairly free of soil or sand and so are relatively easy to clean before using. However, those that creep along the ground, such as thyme and oregano, can easily collect sand or mud on their leaves and stems, making them trickier to clean. In addition, herbs with crinkled leaves and those suffering from pest problems should be cleaned thoroughly under running water.

To remove grit, dust, or other residue, rinse the leaves under cold running water for a minute or two. Or fill your sink with cold water and immerse the herbs in the water. Swish them around, which will cause the debris to drop to the bottom of the sink. Repeat if necessary, then gently pat them dry.

PROBLEMS AND SOLUTIONS

Herbs are among the hardiest of plants. The very qualities that appeal to us—their intense fragrances and the flavors of their essential oils—also keep away most bothersome creatures. When all goes well, homegrown herbs—whether in your garden or in containers—provide a bountiful harvest for cooking, healing, crafting, and many other uses. But when stressed by too little water or light, insufficient nutrients, or poor air circulation, herbs become susceptible to disease and insect infestations that will reduce their productivity and usefulness.

Trouble can be signaled by symptoms that show up on leaves, stems, or fruit: yellowing, browning, or wilting; black or whitish powdery coatings; holes, bumps, or depressions. The symptoms of some conditions overlap those of others, so it’s important to observe a plant carefully to correctly identify and address any underlying causes. The chart on this page details the most common environmental conditions, pests, and diseases that can afflict herbs, along with treatments for each. Solutions for most problems include simple, nontoxic physical barriers and traps; insecticidal soap; horticultural oil; diatomaceous earth; and botanical pesticides. Always use the least-toxic approach before trying others.

PREVENTING GARDEN PROBLEMS

Of course, prevention is the best way to maintain a healthy, problem-free garden. Regular additions of compost will help make essential nutrients available. Plant only healthy herbs—those with consistent, deep foliage color and that show no signs of disease or infestation. Plant herbs only in well-drained soil in sites that receive appropriate light: shade-loving plants in shade, water lovers in moist areas, sun lovers in sun.

Diseases and insect infestations spread rapidly through related plants. As a deterrent, mix different herb species together in beds and other plantings. Lure natural predators of garden pests by planting herbs known to attract those beneficial organisms.

BRING in the GOOD BUGS!

The pollen- and nectar-rich herbs listed below will lure “beneficial” insects—parasitic wasps, ladybugs, lacewings, hover-flies, tachinid flies, and soldier beetles—that attack many common garden pests, including scale, aphids, and whiteflies. Planting them among vegetables and flowers, or in borders surrounding vegetable or flower gardens, will help keep pests in check.

Angelica (Angelica archangelica)

Anise (Pimpinella anisum)

Bee balm (Monarda spp.)

Borage (Borago officinalis)

Caraway (Carum carvi)

Catnip (Nepeta cataria)

Coneflower (Echinacea spp.)

Dill (Anethum graveolens)

Fennel (Foeniculum vulgare)

Lavender (Lavandula spp.)

Lemon balm (Melissa officinalis)

Marigold (Tagetes spp.)

Marjoram (Origanum majorana)

Onions, garlic, chives (Allium spp.)

Parsley (Petroselinum spp.)

Peppermint (Mentha x piperita)

Rosemary (Rosmarinus spp.)

Sage (Salvia spp.)

Spearmint (Mentha spicata)

Tansy (Tanacetum vulgare)

Thyme (Thymus spp.)

Yarrow (Achillea millefolium)

Beneficial insects are a boon to any garden, and herbs are among the best plants for attracting them.

HERB PROBLEMS and SOLUTIONS

ENVIRONMENTAL PROBLEMS

Symptoms: Brown leaf tips

Possible Culprits: Excessive fertilizer, watering, high level of fluoride, boron, or copper in the water

Susceptible Herbs: All plants

Solutions: Change watering and fertilizing habits. If symptoms persist, test water quality.

Symptoms: Poor growth, yellowing leaves, new growth shrivels and dies

Possible Culprits: pH imbalance, lack of nutrients, poor drainage

Susceptible Herbs: All plants

Solutions: Check drainage; test soil. Amend with appropriate additives or repot plant to provide better drainage.

PEST PROBLEMS

Symptoms: Stunted and deformed leaves and stems; plant parts covered with sticky, dark substance

Possible Culprits: Aphids: suck sap from plants, producing a sugary “honeydew”

Susceptible Herbs: Calendula, mint, oregano, and rosemary

Solutions: Spray plants with water or insecticidal soap. Or wipe affected areas with a cotton swab soaked in rubbing alcohol.

Symptoms: Wilted leaves, possibly coated with sooty mold; plant loses vitality and eventually dies

Possible Culprits: Whiteflies: feed on undersides of leaves and can cause extensive damage

Susceptible Herbs: Calendula, lemon verbena, and rosemary

Solutions: Spray plants with water. If indoors, lower growing temperature to decrease whitefly activity. Encarsia formosa, a species of tiny predatory wasp, can be an effective control outdoors.

Symptoms: Yellowish or silvery leaves; severe yellowing and rusty spots; fine webbing on leaves and stems

Possible Culprits: Spider mites: tiny pests puncture plant leaves and stems and feed on sap

Susceptible Herbs: Mint, oregano, parsley, rosemary, sage, and thyme

Solutions: Apply horticultural oil or insecticidal soap. Wash plants with a mild solution of dish detergent and water. Prune heavily infested branches and isolate infested plants.

Symptoms: Holes at edges of leaves; plants are eventually defoliated

Possible Culprits: Japanese beetles: metallic green insect with copper-colored wings that feed on leaves

Susceptible Herbs: More than 200 plant species including basil, borage, and foxglove

Solutions: Remove from leaves by hand. Control larvae with parasitic nematodes and the bacteria milky spore.

Symptoms: Yellow foliage; plants lose leaves, weaken, and die

Possible Culprits: Scale: minute, sap- feeding insects

Susceptible Herbs: Wide range of plants, including bay and rosemary

Solutions: Remove with a soft-bristled toothbrush dipped in rubbing alcohol or insecticidal soap spray. Plant herbs to attract beneficials. Horticultural oils may help.

PEST PROBLEMS

Symptoms: Irregular holes in the middle or at the edges of leaves; plants may be defoliated; shiny slime trails on and around plants

Possible Culprits: Snails and slugs: pests eat seedlings and soft-tissued parts at night and on cloudy, damp days

Susceptible Herbs: Bee balm, calendula, sage, and sorrel

Solutions: Remove by hand daily, then weekly, when numbers drop. Edge beds with copper strips or diatomaceous earth. Trap with boards and rocks, or sink beer-filled saucers set into the ground with the rims at soil level.

DISEASE PROBLEMS

Symptoms: Yellow, drooping foliage; plants turn brown and die

Possible Culprits: Verticillium wilt: a fungal disease

Susceptible Herbs: Mint and many other plants

Solutions: Plant disease-resistant varieties.

Symptoms: Weakened stems with flowers develop a fluffy gray or white growth, which spreads to fruits

Possible Culprits: Botrytis blight: a fungal disease

Susceptible Herbs: Rosemary, scented geranium, and many other plants

Solutions: Destroy infected plant parts. Promote air circulation around plants by cutting back or removing plants that crowd each other.

Symptoms: Yellow or white spots on surface of leaves; crusty orange or yellow bumps on undersides; plants become stunted

Possible Culprits: Rust: a disease caused by 4,000 or so related fungi

Susceptible Herbs: Germander, mint, and yarrow

Solutions: Destroy infected plant parts. Promote air circulation around plants by cutting back or removing plants that crowd each other.

Symptoms: Gray or white powdery growth on leaves; new leaves are distorted in shape; poor growth and low yield

Possible Culprits: Powdery mildew: a fungal disease that thrives in hot weather

Susceptible Herbs: Bee balm, catmint, germander, and lemon

Solutions: Promote air circulation around plants by cutting back or removing plants that crowd each other. Spray affected plants with sulfur, lime-sulfur, horticultural oil, or a weak solution of baking soda and water.

Symptoms: Yellow foliage; brown coloration along leaf edges; plants wilt and become stunted; roots soft and waterlogged

Possible Culprits: Root rot: a fungal disease

Susceptible Herbs: Oregano, rosemary, sage, tarragon, and thyme

Solutions: Use sterile potting soil when propagating plants. Avoid overwatering, but do not let plants dry out between waterings. Remove and destroy affected plants.

Symptoms: Yellow stunted leaves; wilting

Possible Culprits: Nematodes: microscopic wormlike creatures feed on roots, leaves, and stems and spread readily in water and on tools

Susceptible Herbs: Calendula and parsley

Solutions: Remove and destroy infested plants. Amend soil with compost, organic fertilizers, and products containing seaweed.

HERB GARDENING TO-DO LIST BY SEASON

Late Winter through Early Spring

• Start plants. Start herb seeds indoors 6- to 8 weeks before your last expected frost. Also take cuttings from indoor herb plants to propagate new outdoor garden plants. Start herbs outdoors when nighttime temperatures exceed 55°F.

• Prune. Prune woody herbs such as lavender by removing leggy old growth to promote new stem growth and better form.

• Weed. At the beginning of the growing season, pull out weeds while their roots are still shallow.

• Build soil. Add compost or other organic material to your garden beds.

• Rejuvenate beds. Divide and transplant herbs that have outgrown their original sites. Add, remove, or move plants to refresh the design and appearance of your plantings.

Fall

• Plant bulbs and seeds. Plant bulbs of herbs such as garlic and saffron and seeds of caraway, dill, parsley, and sweet cicely, which will overwinter and begin growing in spring. In warm areas, plant seeds of cool-season herbs such as chervil, cilantro, and parsley in a cold frame for winter production.

• Divide. Divide and replant hardy perennials, or note which ones should be divided and moved in spring.

• Clean up. Rake leaves and pull weeds. Remove spent annuals; save their seeds for the next growing season. Leave some stalks and seeds of herbs such as chervil, echi-nacea, fennel, lavender, marjoram, rose, and sweet cicely to feed hungry birds during the dormant season.

• Prepare for the dormant season. Pot (if necessary) and move any nonhardy herbs indoors for the winter.

Spring through Late Summer

• Plant. After the weather stabilizes in spring, plant purchased herbs and transplant seedlings to the garden. Create container plantings. Continue to sow herbs that quickly go to seed (such as borage, cilantro, dill, and fennel) every few weeks to ensure a continuous supply throughout the growing season.

• Mulch. Cover beds with a layer of fresh organic mulch, such as compost, bark, or shredded leaves.

• Water. In arid climates and during dry periods, water herbs occasionally and deeply.

• Weed. Continue to dig up weeds as they appear. Also, monitor invasive herbs, such as mints, to prevent them from spreading beyond their containers.

• Deadhead. Remove spent flowers and seed heads of perennial herbs such as anise hyssop and catnip to encourage new flower production.

• Harvest. Pinch back rapidly growing herbs. Harvest according to herb type.

• Preserve. Dry herb foliage and flowers for later use. Prepare herbal vinegars, oils, infusions, and tinctures.

Winter

• Care for indoor herbs. To keep herbs alive indoors, be sure your plants receive adequate light, water, and nutrients. Monitor for pest and disease problems.

• Propagate cuttings. Take cuttings from indoor herbs and start them for the next growing season.

• Plan for the new growing season. Choose small or large projects for the next year: planting or moving a tree; rerouting paths; or adding new garden beds.

• Make herb products. Use previously harvested herbs to make herbal products and crafts such as potpourris, wreaths, and sachets.

• Read and learn. Now is the perfect time to read about new varieties and growing techniques. If some plantings failed to perform well last season, look for solutions. Also consider joining a garden club or taking a class.

• DIY projects. Build a potting bench, compost bin, coldframe, or enclosures for raised beds.