Undercover Gardening

The following section is often indebted to one of the basic books in this field, William Head's Gardening Under Cover: A Northwest Guide to Solar Greenhouses, Cold Frames, and Cloches (Seattle: Sasquatch Books, 1989).

For fall and winter gardening in chilly or cold climates, and very early spring growing, cover is essential. A garden under cover is protected from rain, frost, wind, and cold. There are 4 styles of light-transparent, cold-protective covering for plants: floating plastic row covers, cloches, cold frames, and greenhouses.

Undercover Garden Suppliers: Check the Yellow Pages in your area. Or contact:

Charley's Greenhouse & Garden specializes in supplies for hobby greenhouses: gardening supplies, climate controls, greenhouse equipment, and more than 100 greenhouse kits (from 2 x 6 ft. to 16 x 37 ft.). Free catalog: 800-322-4707; fax 800-233-3078; 17979 State Rt. 536, Mt. Vernon, WA 98273; [email protected] greenhouse .com; www.charleysgreenhouse. com. Mellinger's offers a good selection of light row and plant covers, soil heating cables, greenhouses, cold frames, etc.: PO Box 157, N. Lima, OH 44452; 800-321-7444; fax 330-549-3716; [email protected]; www. mellingers.com. Teufel Nursery sells both wholesale and retail. Their catalog lists many unusual items, including greenhouse aids: 503-646-1111; 12345 NW Barnes Rd„ Portland, OR 97229. Or in Washington: 425-4821112; 6303-233rd Place SE, Woodinville, WA 98072; www.teufel.com. Info on Indoor Gardening: These books detail methods of gardening under cover that are more advanced than plants on a shelf or windowsill that gets lots of sunshine. Greenhouse Gardener's Companion is by Shane Smith, director of Cheyenne Botanical Gardens; [email protected] org. William Head's Gardening Under Cover: A Northwest

Guide to Solar Greenhouses, Cold Frames, and Cloches (1989); Intensive Gardening Round the Year, by P. Doscher, T. Fischer, and K. Kolb (1981); Successful Cold-Climate Gardening by L. Hill (1981); and Building and Using Coldframes, by C. Siegchrist (1980) are also useful. Advantages of Gardening Under Cover Heat Is Trapped. When a cat lies in a pool of sunlight that is streaming through a glass window on a cold but sunny day, the sun's rays are transformed. The visible sunlight has radiant energy that becomes heat energy when it strikes the cat's fur and other surfaces inside the room. Some of this heat is reflected and radiated into the air inside. As heat, it

cannot easily pass back through the glass, so inside the window the air warms up. A covering over a garden bed acts in the same manner. When light strikes the soil and plants, it is converted into heat, and it warms the environment within the covered space. This warmth speeds up all life processes, including the growth and development of the garden plants.

Protection from Damaging Rain. In the maritime climate of much of the Pacific Northwest, rain is a major cause of crop failure. Wet conditions encourage diseases that rot stems and leaves of plants and may rot germinating seeds. Heavy rains compact the surface of the soil and can wash seeds out of their shallow soil cover. In very cold weather, wet ground freezes to a depth of several inches. Frost and Wind Protection. Coverings particularly protect plants from late-spring and early-fall frosts. Frosts usually occur after a sunny day during which the soil has been warmed. At night, warm air rises and is replaced by freezing air. A covering slows down this air exchange and helps prevent freezing. Winds can knock over plants and lower air temperatures dramatically, even on otherwise sunny days. The cover protects against that, too. Flexibility in Plant/Harvest Dates. How many times have you set out plants only to see them killed by a frost or to watch them sit without growing until warm weather finally arrived? How many times have you nursed your tomato plants through summer only to see the fruit destroyed by an early fall frost or rainstorm? By gardening under cover, you can plant seeds at 2-week intervals over a span of 4 to 8 weeks and discover how much earlier and later you can start your garden beyond the dates recommended on the seed packet. And food, herbs, and flowers grown out of season sell for higher prices.

More Crop Variety. Many less hardy vegetable and ornamental plant varieties that normally would not do well in your area can be grown successfully under cover. Faster Plant Growth. Vegetables and flowers should be grown to maturity as soon as possible because the faster a vegetable grows, the better its chances of resisting disease and surviving bad weather. Plants grown quickly will also be less likely to become stunted and will even taste better. You can also grow more food in less time from that one bit of earth.

Example: In one test in the Pacific Northwest, lettuce planted March 2 and grown inside a cloche was ready for first harvest by midApril. Lettuce planted on the same date in open beds was not ready for harvest until mid-May. In addition, the total harvest of lettuce per square foot was 3 to 4 times greater in the cloche as in the open beds!

Another example: In the same way, tomatoes started and reared in a greenhouse matured earliest. Those planted inside, transplanted to cloches after 4 weeks, and reared there were ready for first picking only 12 days later than the greenhouse ones. But those transplanted to an open garden were not ready for harvest until 5 weeks later than those growing under cloche.

Less Insect Damage. Early-spring and late-fall plantings avoid most garden pests. Crops left in the ground during the winter rarely have insect damage because most of the bad bugs are not eating during that season. The later you plant in the spring, the more likely your plants will have bug bites. Midsummer undercover plantings also escape attack by many pests by maturing in late fall or winter. cloche: a cloche (pronounced "klosh") is a lightweight covering for a plant or plants that can easily be moved. a cloche is the simplest cover to build and use. It can easily be moved to different parts of the garden to cover different plants. When the cloche is put on over tender young plants in early spring, it's called a "hot cap." Unlike cold frames, cloches allow light to reach a plant from every direction. You can reuse cloches to cover as many as 3, 4, or more crops in the same year. Cloches are especially well suited for use in the maritime Northwest, where plants need protection from excessive rain and cold winds more than from very low temperatures. The weaknesses of cloches are their vulnerability to heavy wind and their inability to keep plants as warm as cold frames or greenhouses. Cloche Materials. a cloche can be made of anything that transmits light, so the possibilities for design are nearly limitless. They can be made of cheap materials—cheaper than those needed to make a cold frame or greenhouse. To cover a row of plants or a section of garden, you can build one large cloche or a series of modular cloches that link together. The word "cloche" is French for bell. In Europe, gardeners have covered plots for centuries, and in the 1600s, French market gardeners used a glass jar in the shape of a bell to cover a plant. Now cloches for individual plants may be made of waxed paper, plastic, fiberglass, or glass. Or your cloche may be a big, plastic-covered tunnel or tent that covers entire rows of plants. a wide variety of cloches are avail able commercially, with an equally wide range in prices.

When open-air gardening begins in the summer, wash your cover material, dry, and store in a shady place until needed in the fall.

Homemade Cloche Design. You can scrape together a cloche by making halfcircle hoop rows out of old coat hangers and then covering them with plastic. Or cut out the top, bottom, or side of any 1-gal. plastic or glass jug. To cover a wide raised bed, use sections of hog-wire fencing curved to fit the beds and covered with plastic. But people who speak carpenterese will find much better cloche plans for both tunnel and tent styles in Gardening Under Cover.

Tunnel: In general, the tunnel style is made by stretching 4-mil polyethylene plastic sheeting over a line of half-circle hoops. The hoops are bent and fastened to strips at the top and bottom sides so they will stay put. For example, you could put the plastic over 6 x 6-inch mesh concrete-reinforcing wire. The reinforcing-wire cloche looks like the tunnel style except the wire is arched from where it is nailed to a 10-foot lumber plank over to the other side, where it is nailed to a parallel plank. Then the plastic is put over that. The 2 end openings are covered with more plastic.

To ventilate a tunnel cloche, on cloudy days you open the end away from the wind. On sunny days you can open both ends. A breeze is created by the warm air leaving the cloche. As the weather gets warmer, you'll be able to leave one end open continuously. When the weather gets hot, of course, you take off the plastic and put it away until fall, when the weather gets cold again.

Tent: This cloche is lighter, portable, and easier to build than the tunnel. It has 4- or 6-mil polyethylene plastic sheeting stretched over an umbrella-tent-style support. Using a Cloche. Cloches can be placed over any area of your garden, large or small, that you want to protect. To water, weed, and harvest, you lift the cloche off the bed, tilt up one end, or take off the plastic. If your cloche has no natural opening, you must remember to ventilate by propping up one side.

COLD Frame: Cold frames are temporary structures that cover and protect plants in the garden. They extend the growing season into the fall or through the winter, or help plants get an early start in spring. These temporary structures can be set down over plants in the garden, opened by day, shut at night, and removed when not needed. A cold frame is more rigid and heavy than most cloches, harder to move. It is usually more expensive and time-consuming to build than a cloche—but, once built, is far more durable. A cold frame provides more protection from weather than a cloche but less than a greenhouse. In a mild maritime climate like the Willamette Valley of Oregon, a cloche can get many plants safely through the winter. But since cold frames stay warmer inside than cloches, if you live where there is severe winter cold, you'll need to use one of these for weather that's too much for a mere cloche to handle. You can start frost-tender plants from seed in a cold frame the same way you would start them in a tin can in your house. Or use a cold frame to harden off transplants from the house before sending them on to the garden.

A cold frame is basically a glass or clear plastic window, the lid of a bottomless box. Wherever the box is set down, the ground under it becomes the bottom of the box. Inside the cold frame, you are creating a special area of milder climate. A cold frame is usually a permanent structure.

Choose suitable kinds of plants for the cold-frame style of gardening. Oriental greens such as Green Wave, Mizuna mustard, Florida broad-leaf mustard, Chinese broad-leaf mustard, and edible chrysanthemum (all available from Abundant Life Seed Foundation) are good. Siberian kale and corn salad are good too. The mustards have a remarkable rate of growth and are somewhat slug-resistant. Winter Gardening in the Maritime Northwest: Cool Season Crops for the Year-Round Gardener by Binda Colebrook will help. Soil. The place where you construct a cold frame should have good garden soil—soil that contains enough organic material to drain adequately and that is also very fertile. Consider adding manure too. In a cold climate, self-heating soil can be very helpful! Goat, horse, chicken, rabbit, or pigeon manures give off a lot of heat as they age. If you put a 6- to 8-inch layer in the cold frame, it will turn it into a "hotbed." But wait until it's cooled down some—a week at least—before you plant in there.

Glazing Material. This is the glass or glass substitute in the top of your cold frame or greenhouse windows. Most glazings allow the same amount of light penetration. Where they vary widely is in cost and breakability or durability. Polyethylene is cheapest by far but lasts only 1 or 2 years. Fiberglass is commonly used because it's a good compromise between low cost and long lifespan. Untempered glass is midprice but vulnerable to breakage; it's best used only on vertical installations or small cold frames. Tempered glass is an excellent glazing material and can frequently be purchased inexpensively as blemished or used patio doors. It seems as if every year new glazing products, such as double-wall acrylics, are invented.

Cold Frame Design. A "cold frame" has low opaque walls that support the transparent overhead material, usually a glass or clear plastic lid in a frame. The frame is hinged so it can be raised to let you in to work with your plants and to let in air, but it can also stay down to keep out cold. A cold frame with insulation around all its sides (such as IV2 inches thick) will be warmer inside than one that isn't. In very cold climates, you can also insulate the lid of the cold frame. (In that case, you have to be faithful about lifting it off when the sun's up!) All of the books I have recommended in this section contain more ideas and instructions for building cold frames. In general, the designs are for either portable or permanent cold frames.

Portable: An old-time style of cold frame, called a "light," is as portable as a cloche, though it is heavier. A "light" is basically glass in a frame that fits over some sort of wooden-sided box, which sits on the ground over the plants. Or it can be made of straw, as Earthchild Marie wrote me: "The classic cold frame is straw bales with old windows laid on them at an angle."

From Bill Rogers in Wyoming: "I make them light and portable so that I can put them over vegetables not yet ripened in the fall. In the spring, I locate the frames near a rock or other shelter, exposed to maximum sunlight. Thus I obtain a month or 6 weeks additional on each end of the season, and I have ripe tomatoes or cantaloupes or other vegetables that otherwise I could not have in our short growing season. The earth is over a heavy bed of manure for starting. And for both starting and finishing, I make sure there is plenty of water. I use window sashes from houses that are being wrecked; otherwise the cost of glass would run hot frames out of sight. I use scrap lumber for the frames but extend its life by painting—likewise the window frames and putty."

Permanent: These are at least semipermanent. You pick the best place in your garden for the cold frame, build it there, and there it stays. The best site for a cold frame is well drained, receives the most sunshine possible, and has steady, gentle air movement yet is protected from cold north winds. A gentle slope is good because it will drain easily. Sunshine. Your site should receive full sun from 9am to 3pm because during the colder months, 90 percent of the sun's energy is received between these hours. Beware of shading, and remember that the sun is at a lower angle during fall, winter, and early spring, so trees and buildings to the east, south, and west are more likely to cast shade on your site. For a cold frame to receive maximum winter light, the long axis of the structure should be oriented east-west. The difference in light intensity due to orientation is not great during the summer, when the sun is high in the sky, but it's an important difference in the winter, when the sun is low.

You can combine a raised-bed garden and a cold-frame or cloche design and get good results. The drier soil of a raised bed retains heat better than does wet soil. Rodale Press of Emmaus, PA, offers plans for a "grow frame." Gardening Under Cover has 2 top-notch designs with full construction details: one for a 4 x 4-foot grow space; the other for a 4 x 8-foot Hermeyer cold frame, 30 inches high at the

1. The best defenses against bacterial and fungus problems are well-nourished soil, plenty of sunshine, and plenty of water.

2. Consider companion planting with these plants, which have pest-repellent talents and/or attract pest-eating bugs: marigolds, alliums, evening primrose, wild buckwheat, baby blue eyes, candytuft, bishops flower, black-eyed Susan, strawflowers, nasturtiums, angelica, and yarrow. All are offered by Clyde Robin Seed Co., PO Box 2366, Castro Valley, CA 94546; 510785-0425; fax 510-785-6463; [email protected]; www.clyderobin.com. More than 250 pages of gardening info and photos. Free catalog.

3. To combat greenhouse insect pests, careful screening is the simple, basic answer.

4. In urban areas, the "plant doctor" is the equivalent of the rural vet. You can get a beloved plant diagnosed and treated by the doc's house call, although it costs. It's more likely to need more or less water or more or less light than to suffer from a disease.

5. Move each vegetable's planting place around in your garden every year. This helps avoid a build-up of one kind of pest or pestilence in a part of your garden. Don't let them just lie in wait to eat the same stuff next year. Move the target!

6. Buy resistant seed varieties.

7. Use diatomaceous earth to combat slugs and snails. (It must be dry to work.)

8. Use beneficial insects: ladybugs, predatory mites, praying mantis, beneficial nematodes, parasitic wasps, mealy bug destroyers, etc.

9. Set traps for larger pests.

10. Use sprays of environmentally safe (biodegradable), natural (plant-originated) material such as garlic, hot pepper, pyrethrum, nicotine, or rotenone as a last resort. Or mulch with coffee grounds, etc.

11. Don't leave disease-infected plants in the garden, and don't put them on the compost pile. This goes for clubroot, late blight in tomatoes and potatoes, and any other soilborne contagion. Put them on a separate trash pile or burn them.

back and 18 inches high at the front with transparent material for its front panel to allow in more light. Cloche and Cold-Frame Management: Think temperature and humidity. Ventilate! And water as needed. Ventilation. Except during long freezing periods, open your cold frame or cloche during the day and close it at night. Venting is needed to control temperature and humidity and to provide a change of air for the plants. Venting helps prevent outbreaks of mold and other diseases. (For more venting ideas, see the section on tunnel cloche design earlier.)

Water. Watering "as needed" is not simple! The more you vent, the more you'll have to water, because venting lets moist air escape, and the movement of air through a cold frame or cloche can quickly dry out soil. On the other hand, when a cold frame or cloche is closed, moisture that would otherwise escape to the air condenses on the glazing and returns back to the soil; it's kind of a mini-planet. During damp and cloudy periods, you may not have to water for weeks at a time. To determine if your plants need water, dig down 4 to 6 inches into your bed. If the soil is dry to that depth, water. Or if your plants begin to wilt, water. Hotbed. a hotbed is used to start tender crop seedlings. You make one by adding to your bed a source of heat, such as an electric heat cable equipped with a thermostat. Or make a nonelectric hotbed by filling the bed with a 2 Vi-foot layer of rich, fairly fresh manure, a manure/bedding mix, or raw compost and keeping it wet at night. Put a few inches of straw and then 4 to 6 inches of nice topsoil over that, so your seeds are about 8 inches over the manure. It will keep heating for up to 3 months. Greenhouse Design and Construction: a "greenhouse" is a glass or plastic-walled building large enough for people to stand and move around in. Green houses can extend the living space of a home while at the same time expanding the garden. "Solar" greenhouses are the only kind of interest to ecology- and budget-conscious people.

Good books on the topic include The Food- and Heat-Producing Solar Greenhouse by B. Yanda and R. Fisher

(1981); The Complete Greenhouse Book by P. Clegg and D. Watkins (1978); A Solar Greenhouse Guide for the Pacific Northwest by T. Magee (1979); The Passive Solar Energy Book by E. Mazria (1979); and The Solar Greenhouse Book, edited by J. C. McCullagh (1978).

The truly dedicated may also wish to check out Growing Under Glass by K. A. Beckett (1981); The City Greenhouse Book by P. Chapel (1980); Rodale's Encyclopedia of Indoor Gardening, edited by A. M. Halpin (1980); Horticultural Management of Solar Greenhouses in the Northeast by M. Klein (1980); Greenhouse Operation and Management by P. V Nelson (1985); Gardening for All Seasons by New Alchemy Institute (1983); The Bountiful Solar Greenhouse by S. Smith

(1982); and Growing Food in Solar Greenhouses by D. Wolfe (1981). The wonderful Helen and Scott Nearing wrote Building and Using Our Sun-Heated Greenhouse: Grow Vegetables All Year Round (1977).

Secrets to a Successful Greenhouse Business by T. M. Taylor (1991) comes from a professional greenhouse designer and one of the nation's largest growers. This book will save you money if you want to set up a professional greenhouse operation. It covers organic greenhouse growing, and provides a Nationwide Plant Buyers List and directory for best grower supplies. It tells how to sell to big chains or local markets, how to choose varieties, how to build or buy a greenhouse, including a simple solar greenhouse with poly roof. Send $19.95 (+ $3 s/h) to GreenEarth Publishing: 407-242-2241; 800-927-3084; 5205 Lake Washington Rd., Melbourne, FL 32934; www.greenhousebusiness.com.

hydroponics: Hydroponics is a method of growing crops without soil in a tank of nutrient-rich water. The nutrients are supplied in a liquid form, circulated in the trough. Plants are supported by a mesh or some such so that their roots are in the solution but their stem and leaves are out of it. Most hydroponic systems rely heavily on synthetic fertilizers and relatively high energy and equipment costs; thus, they're the opposite of what advocates of organic farming and sustainable agriculture are striving toward. An even more exciting concept combines fish farming with hydroponic vegetable growing.

The D. W Aqua Farm in Barnstable, MA, has a thriving aqua farm that combines hydroponically growing vegetables, herbs, and flowers with producing striped bass. State-of-the-art technology makes possible a closed-circuit, balanced, controlled environment that produces as much as 20,000 lb. of bass per year as well as organic (no pesticides are used) vegetables, herbs, and flowers year-round. The hydroponic tanks are situated in connected greenhouses. All the nutrients for the plants come from the fish, and the farm's contract to provide food and flowers for an inn and restaurant chain pays for the hydroponic setup.

Hydro-Gardens offers wholesale supplies for serious hydroponic growers. Catalog, of course: PO Box 25845, Colorado Springs, CO 80936; phone/fax 800-634-6362; [email protected] com; www.hydro-gardens. com.

For much more info on this, subscribe to Aquaponics Journal, a bimonthly magazine for hydroponic gardeners who are also raising fish. Cost is $49/yr; 209-742-6869; fax 209-742-4402; PO Box 1848, Mariposa, CA 95338; [email protected] aquaponics .com; www.aquaponics. com/.

The Growing Edge Magazine is a bimonthly on hightech garden systems like hydroponics, bioponics, aquaponics, etc. Cost is $27/yr; 800-888-6785; fax 541-757-0028; PO Box 1027, Corvallis, OR 97339; [email protected] growingedge.com; www.growingedge.com.

There's more info on aquaponics at www.attra.org/ attra-pub/aquaponic.html, and at www.hydroponics. com.au, a marvelous Australian magazine's website.

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