See Quercus
Evening primrose. Late-spring- to summer-blooming perennials.
Description: Oenothera speciosa, showy evening primrose, pink ladies, bears 2-inch, fragrant, cup-like four-petaled flowers in white turning to pink, or uniformly soft pink. Blooms are borne one to a stem on 6- to 15-inch masses of sprawling stems with elongated 3-inch lance-shaped leaves in summer. Zones 5–8.
O. fruticosa, narrowleaf evening primrose, flaunts an abundance of similarly shaped, slightly smaller, bright yellow blooms in small clusters; they open from red-tinged buds in late spring. The 1½- to 2-foot upright reddish stems bear dark green lance-shaped leaves that turn purple in fall. Zones 4–8.
Several species formerly included in the genus Oenothera have been reclassified under the generic name Calylophus. Most of the renamed plants were those known by the common name sundrops.
How to grow: Plant in spring or fall; divide in early spring or after bloom. Evening primroses thrive in full sun or very light shade in average to less-fertile, moist but well-drained soil, tolerating dry soil quite well. Fertile soil encourages rapid spread, especially with showy evening primrose, which spreads by creeping roots and may become invasive unless curtailed every season by pulling up unwanted plants.
Landscape uses: Evening primroses are well suited to borders if their spreading ways are not a problem. Otherwise enjoy them in low-maintenance masses in hot, dry, infertile areas.
Abelmoschus esculentus
Malvaceae
Okra, native to Africa and a beautiful relative of hibiscus, was brought to North America in the 1600s. This tropical plant quickly became popular in the Deep South both as a side dish and as a thickening for gumbo and stews. It can, however, thrive in any climate where corn will grow. Depending on the cultivar, the large-flowered, fast-growing plants reach 2 to 6 feet tall. Varieties with colorful stems and leaves, such as ‘Burgundy’, make attractive garden borders.
Planting: Okra needs full sun. It will grow in ordinary garden soil but does best in fertile loam, particularly where a nitrogen-fixing crop, such as early peas, grew previously.
In the South, plant the first crop in the early spring and a second crop in June. In short-season areas, start plants indoors 6 weeks before setting them out (3 to 4 weeks after the last frost date). Sow two seeds per peat pot and clip off the weaker seedling.
When seeding okra directly in the ground, wait until after the soil has warmed and the air temperature is at least 60°F. Use fresh seed, and soak it overnight or nick each seed coat with a file to encourage germination. Sow seed ½ inch deep in light soil and 1 inch deep in heavy soil; spacing is 3 inches apart in rows 3 feet apart. Thin seedlings to 18 to 24 inches apart, always leaving the strongest of the young plants.
Growing guidelines: When okra is 4 inches tall, mulch to keep out weeds and conserve moisture. Water during dry spells. Every 3 to 4 weeks, side-dress with compost or feed with compost tea. (See the Compost entry for instructions for making compost tea.) In areas with long, hot summers, cut the plants back almost to ground level in midsummer and fertilize to produce a second crop.
Problems: Okra seldom succumbs to pests or diseases. Handpick any stinkbugs that appear; these light green, shield-shaped bugs cause misshapen pods. To control corn earworms, cabbage loopers, aphids, or flea beetles, see the chart. Fusarium wilt, a soilborne disease, is sometimes a problem in hot regions. If the disease causes leaves to yellow and wilt, pull and destroy affected plants. Crop rotation is the best preventive measure.
Harvesting: About 50 to 60 days after planting, edible pods will start to appear. They are tough when mature, so harvest daily with a sharp knife when they are no more than finger-size and when stems are still tender and easy to cut. Pick frequently and the plants will keep producing until killed by frost. Be sure to remove and compost any mature pods you might have missed earlier.
Many people find their skins are sensitive to the pods’ prickly spines, so wear gloves and long sleeves when harvesting, or plant a spineless variety such as ‘Clemson Spineless’.
Allium cepa and other species
Amaryllidaceae
Dried or fresh, raw or cooked, onions are an indispensable ingredient in many dishes and cooking styles. Onions are easier to grow than you might think, and they’re a great plant for tucking into spare corners and along the edges of garden beds.
Types: Onions come in a wide variety of shapes, sizes, and colors. The white, yellow, or red bulbs range in size from small pickling onions to large Spanish cultivars; they can be globe, top, or spindle shaped.
Most onions can be pulled young as green onions called scallions, but there is also a perennial bunching type, Allium fistulosum, that produces superior scallions and is practically disease- and insect-proof. Each bulb of the multiplier or potato onion (A. cepa, Aggregatum Group) multiplies into a bulb cluster, so with every harvest, you’ll have bulbs to replant for a continual supply.
The Egyptian or top onion (A. × proliferum) produces a bulb cluster at the end of a long stem with a second cluster frequently forming on top of the first. It also has an underground bulb, which is often too pungent to eat. Other tasty sources of oniony flavor include chives (A. schoenoprasum), garlic chives (A. tuberosum), and shallots (A. cepa, Aggregatum Group). For information on other onion relatives, see the Garlic and Leek entries.
Planting: You can grow onions from transplants, sets, or seeds. Transplants, which are seedlings started in the current growing season and sold in bunches, are available from nurseries and by mail order. They usually form good bulbs over a short period of time (65 days or less), but they are subject to diseases. Choice of cultivars is somewhat limited.
Sets are immature bulbs grown the previous year and offer the most limited cultivar choices. They are the easiest to plant, the earliest to harvest, and the least susceptible to diseases. They are, however, more prone to bolting (sending up a flowerstalk prematurely) than are seedlings or transplants.
If you plant onion sets, the sets may be identified only as white, red, or yellow, rather than by variety name. Most growers prefer white sets for green onions. When buying sets, look for ½-inch-diameter bulbs, because they’re the least likely to bolt.
Growing onions from seed offers the great advantage of a wide choice in cultivars. The challenge with starting from seeds is that your crop will take up to 4 months to mature—gardeners in cold-winter areas will need to start their onion seedlings indoors.
Always check a cultivar’s daylength requirement or recommended latitudes before you buy, because daylength affects how and when onions form bulbs. Short-day onions, such as ‘Giant Red Hamburger’, will form bulbs as soon as days reach 10 to 12 hours long. They’re suitable for southern latitudes only. Long-day types, like ‘Sweet Sandwich’ and ‘Southport Red Globe’, need 13 to 16 hours of summer daylight in order to form bulbs. They’re the type to grow in more northern latitudes.
Onions like cool weather in the early part of their growth, so plant them in spring, except in mild-winter areas, where onions are grown as a fall or winter crop. Generally speaking, onions grow tops in cool weather and form bulbs when the weather warms.
Plant onion seeds 4 to 6 weeks before the last average frost—or even earlier indoors or in a cold frame. When indoor seedlings are 2 to 3 inches tall, harden them off by exposing them to above-freezing night temperatures.
Outdoors, sow seeds thickly in rows about ½ inch deep. You can try mixing in radish seeds both to mark the planted rows and as a trap crop to lure root maggots away from the onions. Thin seedlings to 1 inch apart, and thin again in 4 weeks to 6 inches apart. For transplants or sets, use a dibble to make planting holes 2 inches deep and 4 to 6 inches apart. Use the closer spacing if you plan to harvest some young plants as green onions. For sets, open a furrow 2 inches deep and place the sets stem (pointed) end up 4 to 6 inches apart, and then fill in the furrow. One pound of sets will plant about 50 feet of row.
Growing guidelines: The practices you use will depend on the specific crop you’re growing. In general, onions grow best if you keep them well weeded. Use a sharp hoe to cut off intruders; pulling or digging weeds up can damage the onions’ shallow roots. Once the soil has warmed, put down a mulch around and between the plants to discourage weeds and to hold moisture in the soil.
Dry conditions cause bulbs to split, so water when necessary to provide at least 1 inch of water each week; keep in mind that transplants require more water than sets do. Onions can’t compete well with weeds, so it’s important to direct water right to the onion roots. Two good watering methods for achieving this are shown below.
If you’ve prepared your soil well, no fertilizing should be necessary. Always go easy on nitrogen, which can produce lush tops at the expense of bulbs. New growth from the center will stop when the bulbs start forming.
Egyptian onions, chives, and shallots require slightly different cultivation from regular onions. Here are some guidelines for growing these onion relatives.
Plant Egyptian onions in fall throughout the country; harvest some in spring as green or bunching onions. In midsummer or fall, miniature bulbs will form at the stem tip, where most onions form flowers. Pick these tiny bulbs when the tops begin to wilt and dry. Use them fresh or store in the freezer.
Plant chives and garlic chives in early spring in rich soil. They will tolerate partial shade put prefer full sun. Seeds are very slow to germinate, so most growers prefer to plant clump divisions, which can be harvested after 2 months. Space the clumps, each of which should contain about six bulbs, 8 inches apart.
Cut the grasslike, hollow tops frequently to maintain production. The pom-pom-like lavender flowers are very attractive—and edible—but always remove the spent flowers to reduce the chance of rampant self-seeding. Dig up, divide, and replant every third year. Transplant to containers and move indoors for winter harvests. Chives are almost as good frozen as they are fresh.
Shallots, a favorite of French chefs, have a blue-green stem that’s used when young. In addition, it has a gray, angular, mild-flavored bulb that’s related to the multiplying onion and is used like a mild-flavored garlic. Shallots will tolerate all but the most acid soils, but dig the earth deeply because the plants put down 8-inch-long feeder roots. However, they have no lateral roots, so space them just 2 to 3 inches apart.
Propagate shallots by dividing bulb clusters. Each clove, in turn, will produce four to eight new bulbs. In February or March, plant them 1 inch deep, barely covering the tip of the clove. Keep the soil weed-free and slightly moist, but don’t fertilize. In early summer, draw the soil away from the bulbs. Harvest shallots as green onions at any time. Cutting the tops off near soil level will produce new tops, and such harvesting actually increases bulb production. Bulbs mature in about 5 months. Pull and store like onions.
Problems: You can generally expect a disease-and insect-free crop. One possible pest is onion maggots: ⅓-inch-long white, legless larvae that travel in line from one bulb to the next and burrow upward to feed on the stems. To reduce the chances of extensive damage, scatter-plant onions throughout the garden. (This interplanting can also benefit other garden plants; many Allium species will ward off pests—such as aphids, Japanese beetles, and carrot flies—from roses, lettuce, carrots, beets, parsnips, and members of the cabbage family.) Placing a thin layer of sand around onion bulbs may discourage adult flies from laying their eggs at the bottoms of the plants.
Barely visible onion thrips tend to attack during hot, dry weather in July or August. They produce deformed plants with silvery blotches on the leaves. Thrips overwinter in weeds, so reduce pest populations by keeping the garden clean. Try spreading a reflective mulch, such as aluminum foil, between rows to confuse the thrips. If you catch the problem early, you can spray plants with Beauveria bassiana or spinosad to combat thrips. As a last resort apply neem to control a serious infestation.
A disease called smut causes a swelling or hardening of leaves just above the neck, which eventually bursts and spills powdery black spores over the plant. Downy mildew, a purplish mold, shows up in midsummer during warm, humid weather. Onions are also subject to pink root, which causes roots to turn various colors and then shrivel, and neck rot, which causes tissues to form a hard, black crust. All these problems are caused by fungi in the soil and can be avoided by rotating crops and by working humus into the onion bed to provide good drainage.
Harvesting: Once onion tops turn yellow, use the back of a rake to bend them over horizontally. This stops the sap from flowing to the stems and diverts the plant’s energy into maturing the bulb. A day or so later, when the tops turn brown, pull or dig the bulbs on a sunny day, and leave them to dry in the sun. Lay the tops of one row over the bulbs of another to help prevent sunscald.
When the outer skins are thoroughly dry, wipe off any soil and remove the tops—unless you intend to braid them. Store in a cool, dry place; hang braided onions or those kept in mesh bags in an airy spot. Such dried bulbs will keep for about 4 months to 1 year.
Watering onions. To water onions efficiently, extend soaker hoses along the row close to the plants. Or open a small trench between rows and fill it with water. This keeps the roots supplied while leaving most of the soil surface dry, inhibiting weed seed germination.
If you can grow houseplants, you can grow orchids. Many orchids are tough, durable plants that will bloom year after year on a windowsill. These sturdy beauties only look fragile and exotic!
Before you buy an orchid, think about where you plan to put it. Different species do best at specific light levels and temperature ranges. You’ll get the best bloom if you match plant to place. Some of the best windowsill orchids and their preferred conditions include:
Paphiopedilum spp., exotic-looking orchids that resemble our native ladyslippers, need low to medium light (an east- or west-facing window) and temperatures between 55° and 75°F.
Phalaenopsis spp., moth orchids, need low to medium light and temperatures between 70° and 80°F.
Cattleya spp., the classic corsage orchids, need medium to high light (a south-facing window) and temperatures of 70° to 80°F.
Equitant Oncidium spp., butterfly orchids or miniature oncidiums, need the same conditions as cattleyas. Very compact growers.
There are two other points to consider when buying orchids. First, although orchids bloom for a long time (sometimes months), when they’re not in bloom, they’re foliage plants. Some paphiopedilums and phalaenopsis have beautifully patterned foliage that makes them attractive even when not in bloom. Second, orchids can take years to reach blooming size. When you buy a plant, specify “blooming size” to make sure it will flower the first year.
Orchids will not grow in garden soil. Instead, use a mix sold especially for orchids or combine two parts Douglas fir bark to one part perlite. Use fine-grade bark for paphiopedilums, medium grade for the others. Buy bark where you buy your orchids—at greenhouses and well-stocked garden centers or through mail-order catalogs. For best growth and bloom, repot once a year, since fir bark breaks down and orchids need a loose, fast-draining medium.
Thorough watering once a week is enough except for large or very small plants. Household humidity that’s comfortable to you (40 to 60 percent) is fine for orchids. (A humidifier will be good for you and your plants!) Or set the pots on pebble-filled trays and add water to the trays to increase the humidity around your plants. Make sure the water doesn’t reach the top of the pebbles. In summer, orchids thrive outdoors; hang them in trees or set them in another shady spot.
Feed orchids twice a month with a balanced organic fertilizer, and give a nitrogen supplement such as fish emulsion at each feeding.
Orchids are remarkably problem-free. Use insecticidal soap to control the most common pests: mealybugs, scale, and spider mites. If a plant shows signs of disease, isolate it, remove affected parts with a sharp, flame-sterilized knife, and watch for recurrences.
Origanum spp.
Lamiaceae
Description: There are many species of oregano, including the annual Origanum majorana, or sweet marjoram (formerly Majorana hortensis). Seeds and plants of O. vulgare are often mistakenly sold as the oregano used for cooking. It is good as an ornamental, but unfortunately it has almost no flavor to contribute to food. The plants have erect, hairy, square stems with oval, pointed leaves up to 2 inches long and small, tubular, rose-purple to white flowers borne on 1-inch spikes.
The oregano to buy or grow for kitchen use is Greek oregano, O. vulgare ssp. hirtum. This small-leaved perennial plant forms low, spreading mounds, with spikes of white flowers rising about 1 foot above the foliage. It is marvelously aromatic. Try two exceptional oreganos for even more amazing flavor: the strain ‘Kaliteri’ and the cultivar ‘Hot & Spicy’. Beautiful golden oregano, O. vulgare ‘Aureum’, adds a bright note to the herb garden or a container with its low form and chartreuse-gold foliage, but it is not as good a culinary oregano as many of the others.
How to grow: Start seeds or buy labeled plants. Site oregano in a raised bed or on a ridge of soil into which you have incorporated some grit or very fine gravel, and lime if your soil tends to be acid. Culinary oregano is not as winter hardy as the purple-flowered O. vulgare, which is hardy in Zones 4–9, but it may survive in Zone 5 if grown in full sun with good drainage, and is reliably hardy in Zones 6–9. It often seeds itself, making lots of nice small plants for spring. If you find it hard to overwinter, grow it in pots and bring them indoors to a cool, sunny window until it’s warm enough to set out again.
Harvesting: Cut the long stems just as the flower heads are forming; harvest immediately after the dew has dried. Dry oregano to preserve the sweet, sharp aroma and flavor, hanging bunches in a warm, dry, dark place or drying stems on a tray in a food dehydrator, then stripping off the leaves, composting the stems, and storing leaves whole until needed. For best flavor, crumble the dried leaves into a dish as you prepare it. Oregano is one of the few herbs that tastes better dried than fresh.
Uses: The purple-flowered wild oregano, or O. vulgare, is useful as dried flower material, as it has good, dark rose-purple flowers that dry well on their wiry stems and look good in wreaths and arrangements. You can also plant masses of it to hold up an eroding sunny bank. Some people claim that oregano tea relieves stomach upsets and indigestion. The white-flowered culinary oregano, used sparingly, will contribute just the flavor needed in Italian, Mexican, or Greek cooking. It’s essential in pizza and marinara sauces and complements tomato, pepper, and eggplant dishes, as well as enhancing recipes made with shellfish and eggs. If you’d like to make your own chili powder, combine dried oregano, dried chipotle chiles, cumin seeds, garlic powder, and salt to taste, and pulverize in a blender or coffee grinder until powdered.
Simply stated, organic gardening is a method that uses our understanding of nature as a guide for growing plants without using synthetic chemical pesticides or synthetic fertilizers. But gardening organically is much more than what you don’t do. When you garden organically, you think of your plants as part of a whole system within nature that starts in the soil and includes the water supply, people, wildlife, and even insects. An organic gardener strives to work in harmony with natural systems and to minimize and continually replenish any resources the garden consumes.
In a natural system—a meadow or a woodland, for example—there’s no need for synthetic pesticides or fertilizers. Some insects eat plants, but natural predators and parasites help keep their numbers in check. Also, nature tolerates some damage. No one worries whether wild plants and fruits have perfect cosmetic quality. Natural ecosystems also make their own fertilizers. Nature’s cycle of growth, death, and decay is continuous. As plants and animals die, rodents, insects, earthworms, and microscopic soil creatures consume their bodies, and nutrients are released. These nutrients feed new generations of plants.
Many gardeners choose the organic method because they want to be good stewards of the environment. They are concerned about pollution of air, water, and soil and about protecting the health of their families and communities. They know that synthetic pesticides can destroy wildlife, bees, and other beneficial insects and may have an effect on food quality and safety. Tending an organic garden connects them with the soil and makes them feel close to nature.
Organic gardening begins with attention to the soil. You regularly add organic matter to the soil, using locally available resources wherever possible. And everyone has access to the raw ingredients of organic matter, because your lawn, garden, and kitchen supply them every day. Decaying plant wastes, such as grass clippings, fall leaves, and vegetable scraps from your kitchen, are the building blocks of compost, the ideal organic matter for your garden soil. If you add compost to your soil, you’re already well on your way to raising a beautiful, healthy garden organically.
Here are some other basic suggestions to help you get started.
Read about gardening and growing plants, especially using the organic method. Learning about gardening is an ongoing process gardeners enjoy throughout their lives.
Learn more about your soil. You may want to have it tested by the extension office in your county or by a private laboratory. Use the results as a guide to bring your soil into balance with a long-term approach—biological changes aren’t instant and may take several years! Add lime, compost, or organic fertilizers as needed. Maintain soil balance by growing green manure crops and adding organic matter each season.
Start a compost pile. Recycling garden wastes and increasing soil organic matter content are two fundamentals of organic gardening. Composting helps you do both. There are many simple designs for compost enclosures, or you can just make a compost heap in a shaded corner of your yard.
Use a plan and keep records. Find out about the plants you want to grow and which types will grow best in your area. Draw a sketch of your garden and decide what will go where, then revise it as you work. Begin a garden journal for keeping records through the season. Stock up on supplies and tools you may need during the gardening year.
Prevent pest problems before they happen. Always check plants to be sure they’re healthy before you bring them into the garden. Keep plants healthy with timely feeding and watering. Create a diverse ecosystem to encourage beneficial insects. Use row covers to exclude pests; build a fence to exclude animals. Remove diseased and insect-infested plant material from the garden. Handpick insect pests and their eggs. Try biological control techniques. As a last resort, use botanical insecticides.
Learn to identify weeds, and eliminate them while they’re small. Be diligent! A light cultivation several times early in the season may be all you need. Don’t let weeds mature and produce seed for the next season.
Organic gardening has deep historical roots, and a relatively recent development in the United States and other countries is the regulation of organic agriculture by the government. In the United States, farmers who want to label their products as “organic” must comply with regulations of the Organic Foods Production Act, which was passed by Congress as part of the 1990 Farm Bill. In response to this legislation, the USDA created the National Organic Program (NOP), which established a certification program designed to assure consumers that foods labeled organic have been grown, processed, or handled in compliance with standards designed to keep the food, as well as agricultural workers and the environment, free of harmful contaminants. The law also covers organic livestock and its meat, eggs, or milk. The program accomplishes this goal by deciding what substances can and cannot be used to feed crops and control pests if the crop is to be designated as organic. For example, to label their products organic, farmers cannot use toxic synthetic pesticides and fertilizers, genetically engineered seeds or other materials, sewage sludge, irradiation, antibiotics, growth hormones, and fresh manure (the manure must be composted or a waiting period must be observed between the application of manure to a field and harvest of any crop that is likely to be eaten raw).
Home gardeners do not need to follow NOP standards, of course, but if you operate a small market garden and earn more than $5,000 from it annually, you must comply with federal standards in order to sell your produce as organic. This entails keeping detailed records of practices and materials, plus on-farm inspections and periodic residue testing. Acceptable practices and materials are set by the US Secretary of Agriculture and the National Organic Standards Board, which consists of organic farmers, organic food handlers and retailers, environmentalists, and consumers. A number of private organizations and some state agriculture departments also operate and enforce their own standards, provided they are consistent with federal guidelines. These organizations also continue to participate in the debate about additional amendments to the national standards for organic food production. For more information about organic certification and NOP standards, see Resources or ask your local extension office or state agriculture department for the names and addresses of certification groups active in your area.
Organic farming can be traced to several historical philosophies that influenced the way farmers raised crops many years ago. The development of organic gardening closely followed that of organic farming, since the practices that farmers used in their fields were often adopted in the home garden.
In the mid-1800s, dominance over the environment was the conventional agricultural philosophy in many Western countries. Scientists considered soil a sterile medium, useful only for holding plants in place. Crop production was a matter of chemistry.
In the early 1900s, the discovery of manufacturing processes to produce artificial fertilizers, the development of modern pesticides, the improvement of transportation methods, and the demand for farm products helped pave the way for increased crop specialization. Chemical farming became the predominant method in North America and Europe.
Charles Darwin was one of the first scientists to study living organisms in the soil. As a result of reports he wrote on his work in the 1880s, several new philosophies about the relationships between soil and plants evolved. Only a small number of modern farmers and scientists accepted these views, which took a holistic approach. They recognized the importance of returning nutrients to the soil, and the roles of soil animals, humus, and organic matter in crop production.
Biodynamics: In the early 1920s, Rudolf Steiner, an Austrian philosopher and author, founded the biodynamic method of farming. Biodynamic farmers embraced the holistic view of the farm as a living system. Both biodynamic and organic gardening methods avoid using synthetic chemicals and strive to produce vigorous, healthy plants that naturally are less susceptible to pest damage. Both methods recycle nutrients through composting and use raised beds, crop rotation, and companion planting.
What sets biodynamics apart from similar gardening practices is the philosophy behind it. Biodynamic gardeners use secret preparations of plant and animal materials to stimulate crop production and place importance on timing farming practices to coincide with phases of the moon. They attempt to understand the true nature of their crops and livestock: in other words, what each plant and animal really needs to grow to its potential. In biodynamic terms, an ideal farm is a self-supporting system. Livestock feed off the land and supply manure. Composted manures fertilize the soil and provide nutrients for new plant growth, completing the cycle of life. Rather than emphasizing measurable yields, biodynamic supporters seek a healthful product produced with minimal environmental impact.
The biodynamic concept also incorporates the theory of planetary influences on plant growth. Biodynamic gardeners believe these forces manifest themselves in plant characteristics such as vigor and nutrient content. Calendars of cosmic rhythms, such as moon phases and planetary events, guide these gardeners in determining ideal times to complete certain tasks, such as planting and cultivation. Biodynamic farming remains a separate and specialized method, practiced more widely in Europe than in the United States. To learn more about it, see Resources.
The organic method: Two independent schools of thought developed in the early 1900s that promoted the importance of humus in soil. Eventually, both schools merged to form what we call the organic method. The new farmers regarded the agricultural environment as a living system that required recycling of organic wastes. They believed that the new synthetic fertilizers and pesticides were fatal to the environment. An explosion of publications in the 1940s promoted this new, organic method. Among them was Organic Farming and Gardening, founded by J. I. Rodale in 1942.
At that time, Sir Albert Howard introduced a special slow-composting system, the Indore method, and wrote eloquently about the importance of humus, soil microbial life, and soil aeration. Lady Eve Balfour, a leader of the organic movement in Great Britain, echoed Howard’s ideas in her book, The Living Soil (1943). Soon after, Rachel Carson published the environmental classic, Silent Spring (1954), which directly questioned the influence of agricultural chemicals on the environment. These books and others helped carry organic farming concepts to farmers and scientists in North America and Europe.
A small segment of farmers adopted the organic method, and more gardeners became aware of their options. There was no longer only one way to grow crops. For many years, the organic method was considered radical or unusual, embraced by some home gardeners but largely ignored by commercial farmers.
Gradually, as concerns about the environment, food safety, and pesticides in the food chain increased, more large-scale farmers switched to organics. They found that the organic method was a viable way to run a farm, not just a garden. Still, the term organic lacked a definition. Attempts to define it often resulted merely in a long list of what organic gardeners didn’t do. Everyone knew that organic growers didn’t use synthetic pesticides and fertilizers. What exactly did they do?
By 1980, farmers and scientists across the nation were asking questions about organics. The USDA responded by offering this detailed definition of organic farming: “A production system which avoids or largely excludes the use of synthetically compounded fertilizers, pesticides, growth regulators, and livestock feed additives. To the maximum extent feasible, organic farming systems rely upon crop rotations, crop residues, animal manures, legumes, green manures, off-farm organic wastes, mechanical cultivation, mineral-bearing rocks, and aspects of biological pest control to maintain soil productivity and tilth, to supply plant nutrients, and to control insects, weeds, and other pests.” This definition officially recorded not only what organic growers don’t use but also the special techniques that they do use to raise crops successfully.
Concurrently, J. I. Rodale’s son, Robert Rodale, was developing the ideas of a larger organic philosophy—regeneration. He coined the term regenerative agriculture. Rodale felt that regeneration of renewable resources was essential to achieving a sustainable form of agriculture. He also believed that regenerative agriculture could nurture new ideas for general social leadership in addition to solving problems in agriculture and gardening.
An important boost for organic farming came in 1988, when the USDA began a program to fund research and demonstrations on what it named low-input sustainable agriculture (LISA), which has since been renamed the Sustainable Agriculture Research and Education (SARE) program. The goal of the USDA SARE program is to advance environmentally sound, profitable farming systems that are beneficial to the surrounding community. SARE administers a nationwide research and grants program and also develops and distributes information about sustainable agriculture; see Resources.
Once market gardeners and farmers realized there were alternatives to the conventional method—and as demand for organic produce increased—a new generation of organic farmers and gardeners began to see many exciting improvements and discoveries, a process that continues today.
If you want to refine your gardening skill or simply learn more about the origins of organic methods, you may enjoy reading books by or about these great leaders of organic farming and gardening.
Sir Albert Howard (1873–1947). One of the first proponents of a holistic approach to agriculture. Howard believed that soil organic matter, humus, and proper aeration play key roles in soil fertility and plant nutrition because they support soil microbial life. Organic gardeners in the United States largely follow the guidelines and methods established by Howard in the early 1900s and published in his book An Agricultural Testament (1940).
Helen (1904–1995) and Scott Nearing (1883–1983). These pioneers of self-subsistent organic farming founded the Social Science Institute, a publishing organization for many of their books and articles that influenced the back-to-the-land movement of the 1960s and 1970s. Their books include The Maple Sugar Book: Together with Remarks on Pioneering as a Way of Living in the Twentieth Century (1970) and Living the Good Life: How to Live Sanely and Simply in a Troubled World (1970).
J. I. Rodale (1898–1971) and Robert Rodale (1930–1990). The Rodales brought the organic method to popular knowledge and acceptance by American gardeners through the books and magazines published by Rodale Press in Emmaus, Pennsylvania. Both authored numerous books about organic gardening, health, and other topics.
Ruth Stout (1884–1980). Known to gardeners as the woman who originated the year-round, mulched, no-work garden. Her gardening books include The Ruth Stout No-Work Garden Book (with Richard Clemence, 1971), How to Have a Green Thumb without an Aching Back (1955), Gardening without Work (1961), and I’ve Always Done It My Way (1975).
Understanding the importance of organic matter is crucial to success with organic gardening. Organic matter is a term that encompasses a wide variety of living or dead plant and animal material, ranging from kitchen wastes and shredded leaves to well-rotted manure and compost. Here’s what adding organic matter to your soil can do.
1.Supply nutrients for plants by providing surfaces where nutrients can be held in reserve in the soil.
2.Facilitate better drainage by loosening soil structure.
3.Store water in the soil.
4.Help increase air drainage.
5.Increase the activity and numbers of soil microorganisms.
6.Encourage earthworms.
You can increase your soil’s organic content by mulching with organic materials such as compost or shredded leaves, or by digging or tilling them into the top several inches of the soil. Then, to maintain a healthy, humus-rich soil, make adding organic matter part of your yearly garden activities.
Organic matter does not remain unchanged once you add it to soil because soil microorganisms act to break it down to simpler compounds. That’s a good thing, because these compounds are then food for your plants. You can renew soil organic matter by side-dressing crops with compost, mulching during the growing season, and mulching or planting a cover crop during winter.
As a general rule, strive to maintain 5 to 6 percent organic matter in your soil. Don’t overdo it! Adding too much fresh organic matter, such as plant stalks, sawdust, and other plant residues and uncomposted manure, can overstimulate soil microorganisms, which then consume so much nitrogen and other plant nutrients that soil fertility temporarily declines.
Keep in mind that in hot, humid climates, organic matter breaks down more quickly than in cool or dry climates. If you want to slow the loss of soil organic matter, cultivate the soil as little as possible, and when you do work the soil, do it gently, by hand, rather than using a rotary tiller.
You can learn more about the importance of organic matter and about materials you can use to increase soil organic matter content by reading the Compost, Cover Crops, Mulch, and Soil entries.
Ornamental grasses are grown for their special decorative value and bring luxurious foliage, showy flowers, or vivid fall color to the landscape. In addition to true annual and perennial grasses, this group also includes sedges, rushes, and other grasslike plants.
Ornamental grasses vary widely in their growth habits. Some, such as prairie dropseed (Sporobolus heterolepis) and Oriental fountain grass (Pennisetum orientale), form clumps of foliage that grow straight upright or arch gracefully. Others, including reed canary grass (Phalaris arundinacea var. picta) and blue lyme grass (Leymus arenarius) spread rapidly from underground stems called rhizomes or aboveground stems cal led stolons. Spreading grasses are ideal for naturalizing or erosion control, but they also can be very invasive. Clump-forming grasses like miscanthus (Miscanthus sinensis) and fountain grass (Pennisetum alopecuroides) also can be invasive due to self-sown seeds. Unless you’re willing to cut off their ornamental flower spikes and dispose of them before they set seed, they can become a maintenance nightmare.
Grasses are divided into two main groups: cool-season growers and warm-season growers. Cool-season grasses grow from fall into spring. They tend to be evergreen and are generally more moisture tolerant. Cool-season grasses usually flower in late winter and spring and grow rapidly during these times; they often slow down or even stop growing in summer.
Warm-season grasses are dormant in winter. They begin growth in spring, bloom during summer and fall, and go dormant with the onset of cool temperatures. Warm-season grasses often display brilliant fall colors, including orange, red, and purple. During winter, the dried foliage and seed heads can be quite attractive.
Grasses can add a new dimension to any garden design. The airy foliage and flower heads bend and rustle with the slightest wind, adding the elements of sound and movement to the garden. Try adding grasses to an herbaceous border, as individual specimens or in a mass. In the landscape, use tall grasses as windbreaks or screens to block an unpleasant view. Sedges and golden hakone grasses (Hakonechloa macra ‘Aureola’ and ‘All Gold’), with their straplike leaves, make a beautiful contrast to other shade plants such as astilbes, ferns, hostas, and hellebores. Grasses such as fescues (Festuca spp.) also make beautiful, low-maintenance groundcovers.
Grasses can adapt to a variety of soil textures from sand to clay. Most grasses are drought tolerant. A site with moist but well-drained, loamy soil of average fertility will suit most of these plants. At least a half day of full sun is usually ideal, although some grasses, such as most sedges (Carex spp.) and hakone grass (Hakonechloa macra), grow well with more shade. In general, those with thin, wide leaves accept more shade and are less drought tolerant.
Grasses require very little maintenance. Fertilize only if you have very sandy soil. Pests and diseases are rarely a problem. Most gardeners cut their plants back close to the ground once a year (generally in early spring). If you leave seed heads for winter interest, the grass may self-seed. Cultivate lightly around clumps in spring to uproot unwanted seedlings.
Routine care is determined largely by whether a plant is a cool-or warm-season grass. The best time to plant, transplant, and divide cool-season grasses is from late winter to early spring or from late summer to fall. Don’t disturb them in summer, when they are dormant. For warm-season grasses, plant, dig plants for transplanting, and divide them from late spring through early summer. Avoid disturbing these grasses in late summer to fall when they are blooming.
Grasses are easy to propagate by seed or division. Sow seed of annuals indoors about 4 weeks before the last frost. Transplant (or sow seeds directly) into the garden after danger of frost is past; thin to 6 to 12 inches apart. Seed is also an inexpensive way of increasing many perennial species, although named cultivars featuring variegated foliage or other characteristics generally do not come true from seed.
To propagate cultivars or renew old clumps, divide existing plants. Lift plants from the ground, separate them into smaller clumps, and replant. For large grasses, which can be very heavy and woody, chop the clump into pieces with a sharp spade, then lift them up out of the hole. To learn more about this technique, see the Division entry.
The plants listed below are clump-forming grasses that will not spread widely in the garden. Two popular ornamental grasses, miscanthus and pennisetum (fountain grass), are not on this list. Though both are highly ornamental, they self-sow lavishly, creating a maintenance problem. The plants in this list, by contrast, are both ornamental and well behaved.
Briza media (common quaking grass): A cool-season grass that grows 1 to 1½ feet high with an equal spread. Showy flowers appear in spring over tufts of green foliage. Zones 4–9.
Calamagrostis × acutiflora (feather reed grass): A warm-season grass growing 3 to 5 feet high and wide. Flowers, which can reach 6 feet, bloom in summer over arching clumps of medium green foliage that turns orange-brown in fall. Zones 4–9.
Chasmanthium latifolium (northern sea oats): This native warm-season grass grows 2 to 3 feet high with an equal spread. Flowers appear in summer over upright arching clumps of light green foliage that bronzes in winter. Plants can spread by enthusiastically self-sown seed. Zones 4–9.
Helictotrichon sempervirens (blue oat grass): A cool-season grass that grows 1½ to 2 feet high and wide. Plants produce flowers in spring but are primarily prized for the 2½-foot-tall clumps of blue foliage. Zones 5–9.
Panicum virgatum (switchgrass): A native warm-season grass with pinkish flowers in late summer to fall. Cultivars such as ‘Dallas Blues’, with blue foliage from 4 to 6 feet tall, are best. May spread some by rhizomes. Zones 5–9.
Sporobolus heterolepis (prairie drop-seed): A native warm-season grass with arching, threadlike leaves that form 15-inch-tall, 2-foot-wide clumps. Fine-textured, 30-inch panicles of flowers appear above the leaves in late summer, and foliage turns orange, then brown in fall. Zones 3–9.
Many plants grown as perennials in warm climates are not hardy enough to withstand the freezing temperatures in northern areas. Northern gardeners can leave these plants outdoors to die at the end of the season or they can overwinter them until the next growing season. Overwintering involves protecting the plant from the cold, either in the garden or in a sheltered place. There are many overwintering techniques, ranging from covering dormant plants with a thick layer of mulch to moving plants to a cold frame, sunny windowsill, or cool basement. What works for one type of plant might be fatal to another. Check individual plant entries for specific overwintering instructions.
An easy way to overwinter some plants is to grow them in containers year-round and use them as houseplants or on the sun porch during winter. Slow-growing woody plants such as lavender, rosemary, and tarragon make the transition from outdoor plant to houseplant and back very successfully and can thrive for many years.
You can hold many types of nonhardy plants, often called tender perennials, indoors over winter. Cutting back, digging up, and potting plants growing in the garden is one option for overwintering, but this may cause transplant shock, especially if the plants are large. An easier way to save tender perennials is to take and root cuttings, and then keep the cuttings indoors over winter. Many summer bedding plants, including impatiens, begonias, geraniums, and coleus, can be overwintered this way. Rooted cuttings take up less space indoors than entire plants, and there is less chance of inadvertently overwintering diseases or insect pests. Take cuttings from your overwintering plants in late winter to propagate more transplants to move outdoors once the weather warms. To keep them from getting leggy as winter progresses, pinch them or keep them under plant lights. See the Cuttings entry for instructions on how to take cuttings.
The fleshy roots of cannas, dahlias, and even four o’clocks (Mirabilis jalapa), along with tender bulbs like caladiums (Caladium spp.) and tuberous begonias (Begonia spp.), can be dug and stored over winter. See the Canna, Dahlia, Caladium, or Begonia entries for techniques to try.
Geraniums (Pelargonium spp.) and other tender plants can be overwintered two ways. Bring them indoors as described above, or force them into dormancy. Forcing dormancy is useful if you’re short on space for houseplants or want to save time and effort on winter care. Put the plant, either potted or with newspaper wrapped around its rootball, in a cool (not below 40°F), preferably dark place for winter. Allow the soil to dry somewhat but not completely; check every few weeks and water sparingly if needed. In spring, replant outside after danger of frost is past or place in a warm, well-lit place and resume watering.
Many tender perennials go dormant by themselves but need protection. Cover them with a thick layer of mulch, or dig and move to a cold frame or cool basement. Overwinter container plants outdoors by packing them in the center of large boxes packed full of leaves. Wrap shrubs and vines that need winter protection, or bury them in trenches (see the Fig entry for more information on burying plants).
