Much of America’s supermarket produce is expected to ripen in trucks, stores or at home after traveling many hundreds of miles from field to table. During the past six years, as Americans’ hunger for fresher, better-tasting food has deepened, the number of home gardens has risen by 8 percent, to 113 million. That’s more than one for every three people.

Organic gardeners and others find that adding a greenhouse provides just-picked fruit and vegetables at their natural peak of ripeness and significantly extends the growing season. Pre-planted seeds and seedlings flourish in the protected environment and provide robust plants for an outdoor garden. Many vegetables, especially greens, can provide multiple harvests in the greenhouse well into the colder months.

Explore Fresh Horizons

Greenhouse gardens are a constant experiment,” says Roger Marshall, author of The Greenhouse Gardener’s Manual, in Jamestown, Rhode Island. “I grew olive trees from seed, but they were sterile, so I had to buy propagated trees. Like my fig tree, everything will eventually outgrow the space allotted for it.”

The plants get nothing unless you provide it, adds Marshall. His two, 300-square-foot greenhouses use 100 gallons of water every three days, some collected in 55-gallon rain barrels. During winters, the unheated greenhouse protects leafy greens and root crops. Hydroponic lettuce and herbs share the propane-heated greenhouse with figs, lemon grass, ginger, galangal and nine citrus trees. He opines there’s nothing like fresh Key lime pie in January.

In Alstead, New Hampshire, Celeste Longacre, author of Celeste’s Garden Delights, uses her home greenhouse to give seedlings a head start on spring. She and her husband, Bob, grow nearly all the vegetables they’ll use for the year in the resulting backyard garden, noting that New Hampshire ranks number three for locavore support according to the national StrollingOfTheHeifers.com/locavoreindex. She recommends, “Start small, with a plant or two, and then make one change a week toward greater self-sustainable living.”

Success Tips

A greenhouse that creates a warm environment for plants during cold weather may also overheat. “Air circulation is vital; vents and fans are necessary to maintain the right temperature,” advises Longacre, explaining that plants can’t breathe in a damp house. She suggests, “Water only when absolutely necessary and at the soil line, not on the leaves. In hot climates, use shade cloth on the top and sides of the greenhouse.”

There are destructive insects and beneficial insects, Longacre says. “Aphids will kill a crop. Ladybugs can eat 50 aphids a day, plus mites and larva. After the aphids are gone, ladybugs like parsley, dill and geraniums for lunch. That will keep them around in case aphids return.” Ladybugs can be ordered online; stick to local species.

Some plants, like tomatoes, eggplant or winter fruits, need pollination that can be applied by hand, but it’s time-consuming. An easier solution is to use vibrating trays to shake pollen loose and fans that distribute it from plant-to-plant.

Southern Climes, Too

Even in warmer climates, a greenhouse has benefits. In Orlando, Florida, sisters Katherine and Jessica Grandey make good use of a 200-square-foot greenhouse of vertical aeroponic towers. No soil or additional watering is used because plant roots receive a nutrient solution. The small space provides the same amount of greens as a one-acre plot of land while using a tenth of the water, maturing from seed to table-ready produce in five to seven weeks.

The siblings donate a portion of their chemical-free crop to GrowGreen4Women, a nonprofit group that supports cancer patients.

Benefits Beyond Veggies

In Norwalk, Iowa, Master Gardener Richard Schreiber, membership director for the Hobby Greenhouse Association, collects succulents and cacti. He keeps his 500-square-foot greenhouse at 50 degrees during chilly months.

“After experiments and mistakes, hobbyists find what works best for them. The resultant mix often includes both flowering and fruiting plants,” says Master Gardener Tom Karasek, the association’s president, in Longview, Washington. “All greenhouses have microclimates for more or less light or humidity and cooler or warmer temperatures.”

For added value, greenhouse gardens act as insulation when situated on a rooftop to reduce heating and cooling costs, plus divert rainwater from drainage systems; the latter being especially valuable in urban zones.

Whatever its size or scope, greenhouse gardening also shelters a sense of community. As gardeners trade vegetables for a fisherman’s excess catch or as a thank-you for the loan of tools, they share both lively fare and their love of discovery.

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Creative Greenhouses

Greenhouses can be elaborate or simple, bought or homemade from recycled storm windows and architectural scrap, designed with peaked roofs, hoops or geodesic domes. Some are set on a raised platform to stay above snow and flood levels. Kits at home improvement stores come in many sizes; Ikea even has a mini-greenhouse suitable for a windowsill. Sustainable passive solar models are the latest twist. Add a hammock or lounge chair for a tranquil getaway spot.

A whimsical greenhouse built on a platform allows for deep Canadian snows. Recycled 1800s windows comprise both walls and roof with colorfully painted decorations safeguarding birds as they fly nearby (Tinyurl.com/Window-Greenhouse).

Built in 1936, the art deco-styled Jewel Box, in St. Louis, Missouri, is an outstanding example of greenhouse design, with more than 15,000 square feet of vertical glass and five stair-stepped roofs. Horizontal metal surfaces prevent weather damage (Tinyurl.com/JewelBoxGreenhouse).

Washington State Environmental Chemist David Stone built a greenhouse using Ferrock, a carbon-negative material he invented as a cement substitute. Inside it, winter temperatures remain at 60 degrees, even though it’s near the Canadian border (Tinyurl.com/Eco-Greenhouse).

In Mesa, Arizona, a swimming pool is home to tilapia and chickens, wheat and grapes, tomatoes and sweet potatoes. The closed-loop aquaponic farm is an almost entirely self-sustaining ecosystem (Tinyurl.com/PoolGreenhouse).

For more ideas, visit Tinyurl.com/Building-Greenhouses and Tinyurl.com/SalvageGreenhouses.

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