As the photo above suggests, hoophouses are structures with clear polyethylene film stretched over steel arches. Most hoophouses serve mainly as greenhouses, but ours also serves as workshop, storage shed, exercise room, writing room, wildlife blind, and photo studio — fine music playing in the background. Whether the day is sunny, cloudy, or rainy, the poly film admits bright-enough light to work by. And the patter of rain on the translucent roof soothes the soul.
In winter, a hoophouse can also function as a sun-therapy room and tanning salon. Even on the coldest days, sunlight can raise temperatures so much that you need to open the doors and end-wall vents. From spring through fall, it can even serve as a bedroom for overflow guests — albeit good-natured ones.
Point is, a hoophouse creates a wonderful space, and ours has dramatically improved our lives.
Greenhouse Use
In our region, with coldest temperatures dropping below 0°F, it's possible to grow and harvest herbs and leafy greens inside a hoophouse throughout winter without the aid of artificial heaters, though in this case the roots need to be in the ground and not in pots, and you need to insulate them within ground-hugging cold frames. In such conditions, greens may get nipped by frost but usually won't die, though reduced sunlight slows growth to a standstill. Even so, you can harvest greens through November for sure and then again with increasing growth in March. With heaters, of course, you can easily grow almost any plant year-round.
If you prefer to reserve floor space for other activities, you can still keep seedlings of cold-hardy plants going in flats and pots into November or so, before transplanting into an outdoor cold frame, where they'll become increasingly dormant, and may even freeze brown above the surface. But, with any luck, as spring approaches the roots will usually survive and send forth salad leaves for harvest by early April.
Where you're not planning to grow things, consider laying a floor by putting down heavy-duty landscape fabric and then applying several inches of 1/2-inch crushed rock. For a 12x20-foot floor with a three-inch depth, total cost including delivery would be about $150. (For sources, check the Yellow Pages under "Sand & Gravel.") The landscape fabric allows spilled water to drain into the earth, leaving your floor dry and pleasantly crunchy. Such drainage also reduces the hazard of electrical shock that would be posed by wet concrete floor.
Uses for Your Hoophouse
• As Workshop & Storage Shed: A hoophouse is far less expensive than any wood structure with comparable floor space. There's plenty of working light during the day, even on rainy days. Still, an electric line greatly increases your options for tools and evening work. And 4-foot-wide door allows storage of a lawn tractor, which we cover with a tarp so the sun doesn't degrade its tires and seat. Some folks even cure lumber and firewood inside.
• As Exercise Room: A hoophouse is a perfect room for exercise equipment. The bonus I didn't anticipate was the cushioning effect of the crushed-gravel floor, which can allow you to jog in place for extended periods without joint-jarring effects of asphalt or hard floors.
• As Writing Room: Whether writing by hand or on a laptop to background music, you'll wonder why you waited so long to try this. By the way, within the polyethylene shell, music sounds far clearer and livelier than in a furnished room.
• As Wildlife Blind: Poke a telephoto lens through the storm-door window and await visiting wildlife, while reading or keyboarding an article for AboutTown.
• As Photo Studio: A professional photographer needs no better space for a variety of indoor shooting in ambient light. In this case, white fabric panels can soften direct sunlight, and reflector boards can bounce sunlight into shadows. Besides, with an electric line, you can easily suspend studio lights from the steel arches, freeing floor space and eliminating the chance of tipping light stands.
• As Tanning Salon: Occasional winter days in the hoophouse can provide a Florida tan, though your physician would instead advise protecting your skin with a wide-brim hat, long pants and shirt sleeves, and sunblock.
Do-it-yourself vs. Pro Installation
Although handy folks can install hoophouses themselves, it's often wiser to hire an experienced installer or get help from a carpenter who's installed at least one hoophouse. Besides, an experienced installer can be invaluable in suggesting options for connectors, special features, and end-wall materials. Conveniently, most end-wall materials are available at home centers — others through mail-order suppliers.
Instruction manuals? Hoop distributors market almost wholly to professional growers — nurseries, garden centers, and farmers — who routinely put an acre or more under hoops. In phoning around, I haven't yet found a distributor that offers illustrated installation manuals for homeowners.
Siting the Hoophouse
Check with municipal officials whether a hoophouse would be allowed on your property and what "setback" distances from neighboring property lines are required. The ground should be fairly level, though slopes of an inch or two don't matter. After obtaining a building permit from municipal authorities and maybe the blessing of neighbors within eyeshot, you can order materials.
Also check with officials as to means of determining locations of underground utility lines on your property, for you'll need to drive ground posts about 2 feet into the soil to receive the hoops. Utility companies will happily send a representative free of charge to help you map underground lines and avoid breaching them. Certain that you won't damage underground utility lines when driving posts, mark approximate positions of the four corners. It's important that your corners be perfectly square.
Building the Hoophouse
Ground posts about 3 feet in length are driven 2 feet deep. Other ground posts are spaced at 4-foot intervals along the outer length of the floor. Hoops are then inserted into ground posts and fastened with carriage bolts. Depending on supplier, you'll be advised to secure ground posts vertically to a 2 x 10 side board or to fasten angled steel supports.
To avoid being blown into the next county, it's wise to install roof poly on a calm day, pulling it only taut enough to remove fold wrinkles, rather than stretching it tight as a drum. Poly expands and contracts on a daily basis.
I was amazed at my contractor's ingenuity in addressing my request that the south end-wall be translucent. For aesthetic reasons we needed to orient the structure's long axis north-to-south, which ran contrary to most advice regarding orientation for greenhouse growing. Instead of using bulky 2x4s to frame the south end-wall he used lengths of 1-1/4-inch-square hollow steel available at home centers and welded them to each end hoop at the top and to a length of hollow steel along the bottom. Then, ingeniously, he created a steel door jamb that secured a standard storm door. To that he made one side swing open an extra foot to admit the lawn tractor. To that end-wall framing, he attached clear plastic double-wall polycarbonate panels.
Of course, for plant-growing purposes, end-walls oriented east and west don't need to be translucent because the sun follows a southerly arc, bathing the poly throughout the day. For our north end-wall, our contractor simply framed with 2x4s and sheathed them with T-111 outdoor-rated plywood that we painted barn red.
Heating, Insulation, Ventilation
Because the polyethylene film is a poor insulator, electric heat is cost prohibitive. But a variety of greenhouse heaters — propane, kerosene, and oil — vented outdoors can fairly economically protect plants on cold nights if you cover the plants with poly film, so it functions like a cold frame inside the hoophouse.
We have only one layer of poly film over our six hoops. It's survived the sun's UV rays for three winters. We'll try a fourth winter before replacing it. However, Bud Peltz, of Griffin Greenhouse & Nursery Supplies advises installing two poly layers, and using an electric blower to inflate the air between them, thereby creating a pillow effect. The air layer provides a modest amount of insulation, but more importantly, reduces the chafing of poly film against the hoops. The pillow also helps the roof sluff off snow. Blowers are designed to run 24 hours a day throughout the year, at a cost of about $5 per month in wattage, according to Peltz.
For ventilation, we have side-wall poly aprons that roll up a few feet as we crank a handle on a long steel pole that extends the length of each sidewall. Rolled up, the aprons provide almost 60 square feet of ventilation on each side. Under the rolled-up side walls are long panels of mosquito screening. In each end wall, we have a household storm door with sliding/removable glass panes and screens.
With the resulting four-wall ventilation, we haven't needed electric fans in warm weather. There's also a low-tech means of reducing heat gain in summer: You can drape a specially manufactured shade cloth over the roof. Just remember to remove it before snowfall.
Hoop Widths
It appears that the narrowest width available from major distributors is 14 feet. However, Griffin's Bud Peltz says that you can pull 14-foot bows into ground posts spaced only 12 feet. We had bows specially bent at a Connecticut supplier to 12 feet. That tighter bend gave us a taller peak height of 7 feet. 6-inch taller side walls, and a somewhat steeper roof curve that helps shed snow loads. Unfortunately, our Connecticut supplier is no longer interested in dealing with homeowners who merely order "six little hoops" and ask too many time-consuming questions.
Costs
Costs can be surprisingly low. Hoops may cost less than $50 each, so the six hoops needed for a 20-foot house would cost less than $300, excluding shipping, which in our region is done on large flatbed trucks at about $160 from two sources: New Jersey and Pennsylvania. To hoop cost, add a standard boxed roll of 24x100 6-mil polyethylene film at about $150. That amount yields enough film for a couple of roof changes, one change every three to four years.
Labor can be entirely free if you or friends are handy. For example, anyone who can construct a small shed can easily erect and build end walls for a hoophouse. Local contractors with a helper or two might need only a day or a few days, depending on the features you want. Again, special hardware can save construction time and otherwise look far better than improvised connectors and fittings.
Other costs are entirely up to you, depending on the sophistication of ventilation and insulation, as well as end-wall beauty and light transmission. For each end wall, a storm door, local lumber, and stapled poly film can serve adequately. The special connectors for poly and bows at end walls may run less than $200. They're worth it.
Municipal code may require that you install a separately metered electrical line. Costs vary, depending on electric companies and electricians.
Source
Even if you decide on a local contractor, it pays to talk to tech-service reps at distributors, who know the latest options.
• Griffin Greenhouse & Nursery Supply, Latham, NY. Phone (518) 786-3500. Fax (518) 786-3586. Their hoops are delivered from a manufacturer in New Jersey, with an approximate $160 trucking fee. Griffin itself delivers all other materials for $10, if orders exceed $250. Ask for Bud Peltz, who's agreed to answer your questions.
Neil Soderstrom is a gardening writer and photographer based in Wingdale, NY, also found at www.agpix.com/soderstrom.
