Think of hoop houses, row covers, and cold frames as small, unheated greenhouses that can extend growing seasons in either direction; imagine earlier springs and later summers.Read More
|Chickens enjoy a warmer climate where they can still scratch on the ground, while the plants get a heated home in which to grow.|
A recent partnership between Redwood's food pantry, Hearts for Youth, the Redwood Neighborhood Association, and Better Farm utilizes Redwood's Community Greenhouse to cultivate food that will be donated to the food pantry for disbursement to those in need. That greenhouse was moved to Better Farm, where the people staying here have agreed to tend to the garden and provide daily care for the plants as they grow.
I began looking into ways to heat greenhouses year round and found a ton of information on heaters, solar panels, fans and insulation. But all potential solutions fell by the wayside when I discovered Anna Edey and her work on Martha's Vineyard with her Solviva Greenhouse.
|A basic Solviva greenhouse design, as found at Backyard Chickens.|
Awed by this potential, I brainstormed ways to protect plants while keeping them in the greenhouse with chickens. There are a lot of added bonuses to this chicken-greenhouse setup besides the plants, of course. The chickens also enjoy a break from all the cold and wind, which will boost their egg production throughout the winter. Plus, all the bedding and compost will be perfect to shovel into the garden come spring.
To prep the greenhouse, a few things had to be done first. The outside of the structure had to be wrapped in chicken wire to prevent predators from simply scratching through the plastic:
A trap door was added next to the front door to allow birds access outside on manageable winter days (accomplished here without having to leave the main door open and potentially subjecting plants to a chill):
And lastly, the birds needed a protected space to sleep and lay that even a weasle can't get into in the middle of the night:
All the materials we used for this project were upcycled scraps of chicken wire from the herb gardens, handles from a kitchen demolition project on Fishermans Rest Island, and plywood scraps leftover from a construction project in June. We pulled a ramp from one of the other chicken coops, moved the water dishes and food to the greenhouse, and began catching birds we found huddled up outside. They couldn't be happier to discover there are still some places with green grass:
The project is officially underway. In the coming weeks we'll be tracking overall temperature in the greenhouse to determine whether the birds are able to produce enough heat, along with passive solar, to keep the greenhouse above 60 degrees all winter long. If early findings are promising, we'll be adding shelving in the greenhouse to fill it top-to-bottom with yummy plants for food pantry patrons.
Want to design a Solviva Greenhouse of your own? Get in touch with us at email@example.com.
|The belles of Better Farm transport Redwood's Community Greenhouse to its new home.|
Local organizations Hearts for Youth, Redwood Neighborhood Association, and Better Farm have teamed up to provide volunteer hours that will cultivate fresh, organic produce earmarked specifically for use by the Redwood Food Pantry in order to provide local residents with healthy, local food.
|Redwood Community Greenhouse.|
To that end, the Community Greenhouse has been relocated to Better Farm in order to receive the round-the-clock attention and watering a summer greenhouse requires; while also taking advantage of the extended growing season a greenhouse can provide. In the greenhouse's former home along Route 37 in downtown Redwood, raised beds have been constructed for public use. Now a community garden, it is the hope of these partnered organizations that people within the hamlet who do not have access to a garden will take advantage of the Redwood Community Garden to grow veggies from corn to broccoli.
|Xuan Du and Kathryn Mollica fill raised beds in Redwood's Community Garden. |
Lean-to greenhouses can contribute greatly to heating your home in the winter with their passive-solar capabilities—just vent the top into your second-floor, or open up a slider or window into the space for warm air all day long.
Hobby Greenhouse, they've got really simple and free plans to download basic lean-to greenhouse designs for a simple 8' x 12' lean-to greenhouse framed with 2' x 4' redwood or cedar and covered with rigid Lexan polycarbonate panels. Once the foundation is complete and all the supplies are on hand, two people can complete this lean-to greenhouse in a weekend. For energy efficiency it should be constructed around a door or window and insulated.
Backwoods Home Magazine features a first-person account of constructing a lean-to greenhouse with tips on finding inexpensive glass and troubleshooting advice. And Live Science offers information on a home that, with solar collectors working in tandem with a lean-to greenhouse, went 25 years without a heating bill.
|Image from West Virginia University.|
The main components of lean-to greenhouses are pretty straightforward. A lean-to greenhouse is a half greenhouse, split along the peak of the roof, or ridge line. Lean-tos are useful where space is limited to a width of approximately seven to twelve feet, and they are the least expensive structures. The ridge of the lean-to is attached to a building using one side and an existing doorway, if available. Lean-tos are close to available electricity, water and heat. The disadvantages include some limitations on space, sunlight, ventilation, and temperature control. The height of the supporting wall limits the potential size of the lean-to. The wider the lean-to, the higher the supporting wall must be.
|Image from West Virginia University.|
Temperature control is more difficult because the wall that the greenhouse is built on may collect the sun's heat while the translucent cover of the greenhouse may lose heat rapidly. The lean-to should face the best direction for adequate sun exposure. Finally, consider the location of windows and doors on the supporting structure and remember that snow, ice, or heavy rain might slide off the roof or the house onto the structure.
- Location: South-facing windows will obviously get the most sun, but morning sunlight on the east side is sufficient for most plants. Morning sunlight is most desirable because it allows the plant's food production process to begin early and maximizes growth. An east side location captures the most November to February sunlight. The next best sites are southwest and west of major structures, where plants receive sunlight later in the day. North of major structures is the least desirable location and is good only for plants that require little light.
- Drainage: If flooding is an issue where you live, build your greenhouse above surrounding ground so rainwater and irrigation water will drain away.
- Size: An attached greenhouse can be a half greenhouse, a full-size structure, or an extended window structure. There are advantages and disadvantages to each type.
- Foundations and Floors: Permanent foundations should be provided for glass, fiberglass, or the double-layer rigid-plastic sheet materials. The manufacturer should provide plans for the foundation construction. Most home greenhouses require a poured concrete foundation similar to those in residential houses. Quonset greenhouses with pipe frames and a plastic cover use posts driven into the ground. Permanent flooring is not recommended because it may stay wet and slippery from soil mix media. A concrete, gravel, or stone walkway 24 to 36 inches wide can be built for easy access to the plants. The rest of the floor should be covered by several inches of gravel for drainage of excess water. Water also can be sprayed on the gravel to produce humidity in the greenhouse.
|Checking out neighbor Rick's four-season greenhouse design. Photo/Dave Ciolli|
We're particularly excited about the new topic room, as we prepare to create our own hoop house/greenhouse next month that will allow us to provide the community with fresh greens from early spring through early winter (yes, even in the tundra of the North Country!). SARE's free advice, tutorials, and in-depth information is giving us all the tools we need to make our vision a reality.
Information products in the Season Extension Topic Room derive from SARE-funded research and education projects, and are organized according to key topic areas: Overview; Types and Construction; Variety Trials and Selection; Fertility Management; Pest Management; Water Management; Energy; and Marketing and Economics. While the Season Extension Topic Room includes extensive information on high tunnels (also known as hoop houses), some materials also address greenhouse and nursery production, low tunnels and winter storage.
Examples of what the Season Extension Topic Room offers:
- High Tunnel Specialty Crop Production in Colorado. This April 2011 webinar, presented by Colorado State University Extension and USDA Natural Resources Conservation Service (NRCS), gives an introduction to high tunnels and addresses design considerations, summer and winter production, economics, and future research needs.
- Greenhouse Energy Conservation Strategies and Alternative Fuels. This series of bulletins, curriculum materials and other resources was developed by the University of Wisconsin, and is intended for Cooperative Extension educators, college instructors and high school vocational agricultural teachers.
- Organic Control of White Mold in High Tunnels. This Kentucky State University video describes two organic practices for controlling white mold-solarization and biofumigation.
- Expanding Winter Harvest and Sales for New England Vegetable Crops. This website, hosted by University of Massachusetts Extension, includes information on high tunnels and low tunnels, winter storage, and strategies for marketing produce in the winter.
Recognizing the role that high tunnels can play in diversifying farmer income while meeting growing consumer demand for local food, NRCS offers grants that help pay for high tunnel construction. In 2010, its first year, the program led to the construction of 2,400 structures in 43 states in 2010.
The Season Extension Topic Room will be updated with new resources as they become available. Check out the page here: www.SARE.org/Season-Extension.
The Season Extension Topic Room will be updated with new resources as they become available. Check out the page here: www.SARE.org/Season-Extension.
|Children planting seeds in Redwood's Community Greenhouse. Photo/Penny Heath|
|Participants in Saturday's seed-planting workshop. Photo/Penny Heath|
|Erin Fulton paints a "Community Garden" sign. Photo/Dave Ciolli|
At the workshop, participants learned about proper methods for planting and caring for seeds. Planted on Saturday were lettuce, various kinds of tomatoes, zucchini, and broccoli.
Those plants will be nurtured until June, when they will be sold in a plant sale to benefit the Redwood Neighborhood Association. For more information about the greenhouse, to volunteer, or to participate, please call (315) 482-2536 or e-mail firstname.lastname@example.org.
|Nicole Caldwell waters seeds in the greenhouse. Photo/Dave Ciolli|
|Image from Neo-Farms.com|
The Walipini (underground or pit greenhouse) in this bulletin is designed specifically for the area of La Paz, Bolivia. However, the principles explained in the bulletin make it possible to build the Walipini in a wide variety of other geographic and climatic conditions. The word ‟Walipini” comes from the Aymara Indian language of this area of the world and means ‟place of warmth”. The Walipini utilizes nature’s resources to provide a warm, stable, well-lit environment for year-round vegetable production. Locating the growing area 6’- 8’ underground and capturing and storing daytime solar radiation are the most important principles in building a successful Walipini.
I. How the Walipini Works
|Image from Peswiki.com|
The Earth’s Natural Heat: Why dig in?
More Free Energy: The Sun
Energy and light from the sun enter the Walipini through the plastic covered roof and are reflected and absorbed throughout the underground structure. By using translucent material, plastic instead of glass, plant growth is improved as certain rays of the light spectrum that inhibit plant growth are filtered out. The sun’s rays provide both heat and light needed by plants. Heat is not only immediately provided as the light enters and heats the air, but heat is also stored as the mass of the entire building absorbs heat from the sun’s rays.
Heat Storage: Mass and the Flywheel EffectAs mass, (earth, stone, water -- dense matter) comes in contact with sunlight, it absorbs and stores heat. The more dense the mass (water is more dense than rock and rock is more dense than soil) the more energy can be stored in a given area. Mass of a darker color such as flat brown, green or black absorbs heat best. Light colors, such as white, reflect heat best. As the earthen walls of the Walipini absorb this heat they charge with heat much like a battery charges with electricity. This storing of the heat in the mass of the soil is often referred to as the ‟flywheel effect”, with the flywheel being charged in the day (storing heat/energy) and spinning down or discharging at night as heat/energy flows from the earthen walls out of the greenhouse up through the plastic glazing to the colder night air. The amount of heat stored in the mass is a critical factor in keeping crops from being frost bitten or frozen during the coldest nights of the winter. These critical nights are usually encountered around the time of the winter equinox (June 21 in the Southern Hemisphere and December 21 in the Northern Hemisphere). The Walipini is usually designed to absorb more of the sun’s rays/heat during the three coldest months of the winter than during any other time of the year. The key here is to have enough energy stored in the mass so that on the coldest nights, the plants are not damaged. In general, nighttime temperatures should not be allowed to drop below 45º. This minimum temperature is also dependent upon the types of crops being grown, as some are hardier than others and may require colder nighttime temperatures. An easy way to increase the mass is to put a few 55 gallon drums filled with water and painted flat black along the back wall of the Walipini. Some growing space will be lost, but the heated water will greatly enhance mass heat/energy storage and will provide preheated water for plant irrigation. Preheated water reduces plant shock, thus, assisting plant growth.
Cutting Down Heat Loss: Insulation
A double layer of plastic sheeting (glazing) should be used on the roof. This provides a form of insulation and slows down the escaping of heat during the nighttime. This sealed dead-air space between the plastic sheeting should be between 3/4” to 4” thick. Poles used to span the roof that are 3.5” to 4” in diameter provide the indicated thickness of dead air space when plastic sheeting is affixed to the outside and the inside of the roof’s structure. The inside sheeting also keeps the inside humidity from penetrating and rotting the wooden poles spanning the roof.
All above-ground walls should be bermed with as much soil as possible. This provides some extra mass, but provides much more insulation against above-ground cold temperature, winds and moisture penetration.
When nighttime temperatures are continuously well below freezing, insulated shutters made from foam insulation board or canvas sheets filled with straw or grass can be placed over the glazing. This requires more work and storage, and in many environments is unnecessary, such as is the case in the area of La Paz, Bolivia.
II. Location of the Walipini:
The Danger of Water PenetrationWater penetration of the walls and/or floor of the Walipini is destructive. If water seeps through the walls, they will collapse. If water comes up through the floor, it will adversely affect plant growth and promote plant disease. Dig the Walipini in an area where its bottom is at least 5’ above the water table. When all of the above ground walls are bermed, a layer of water-proof clay, such as bentonite, or plastic sheeting, should be buried approximately 6” to 1’ under the berm surface. It should be slanted so that the water drains away from the Walipini to the drainage ditches. In some cases where the soil has a low permeability rate, the clay or plastic may not be necessary. Be sure to dig a shallow drainage ditch around the perimeter of the Walipini which leads run off water well away from the structure.
Digging into the Hillside
Walipinis can be dug into a hillside providing the soil is stable and not under downward pressure. Since the Walipini has no footing or foundation, a wall in unstable soil or under pressure will eventually collapse.
Size and Cost Considerations
The Walipini is designed to keep costs as low as possible using the following: 1) Free labor -- the builder’s and that of friend’s and neighbor’s; 2) Only unlined, inclined, interior earthen walls; 3) Traditional concrete footings and foundations are excluded because they are unnecessary, when the perimeter of the building is protected from water penetration; 4) Plastic ultraviolet (UV) protective sheeting on the top and underside of the roof instead of glass or corrugated fiberglass panels; 5) The most economical, durable materials found thus far for spanning the roof are 4” eucalyptus poles or PVC pipe; 6) The top soil from the dig is used at the bottom for the planting soil; 7) The rest of the soil from the dig is used for the rammed earth walls, berms and adobes; 8) Stones and any gravel from the dig are used in the planting area drainage system and sump-wells; and 9) Used materials are utilized where possible and practical such as used, cleaned 55 gallon oil drums, used doors, etc. It is assumed that only some of the materials will have a monetary cost and that labor will have none. The cost of materials will vary from location to location and will also vary according to what is available free of cost. Materials for the current La Paz models (20’ x 74’) are $250 to $300.
Water Collection Heating/Irrigation System
This system collects runoff from the roof at the front of the roof in a galvanized metal or PVC rain gutter. From the gutter water flows through a pipe into the 55-gallon barrel/drum system used for irrigation and mass heat storage.
Each of the barrels is connected by overflow piping at the top with the overflow pipe at the last barrel exiting at ground level under the back berm to the perimeter drainage ditch.
In case of a down-pour or continuous excessive rain, it would be wise to have a T pipe/valve at the bottom of the gutter so that the runoff can be diverted to an outside perimeter ditch instead of moving down to the already full barrel system. How much run off the system can handle in a given period of time will depend upon the size of the gutter and the diameter of the pipe used. The larger the diameter, the more volume of water can be handled. As previously indicated, this system provides not only preheated irrigation water, but a dense solar mass (water) in which additional heat is stored for the cold winter nights.
IV. Building the Walipini
Hammers, shovels, picks, saws, wheelbarrows, crowbar, forms for rammed earth compaction (two 2 ‟ x 12” x 6’ planks held together by 2” x 4” or metal rods or many other type of forms can be made), 100’ and 25’ measuring tapes ( If 100’ tape is not available, measure out and mark 100’ of string or rope), levels, clear hose for corner leveling, cutting knives, hose, nozzle, hand compactors, adobe forms, drill, bits, stakes, nylon string, etc.
Materials List for a 20' x 74' WalipiniWater
20 -- 4” x 16’ poles or PVC pipes to span the roof
3 -- 3’ x 6’ hinged doors (one is for the 3’ x 5’ vent cover)
3 -- 3’ x 5’ door frames ( 2 if rear wall vent is not used)
2 -- 3’ x 6’ door lintels
1 -- 6’ x 3’ vent lintel or roof frame for vent, if used
1700 sq.’ of 200 micron agrofilm (polyethylene UV plastic)
640’ of 1” wood stripping to secure plastic sheeting to the poles
Shovels, tractor or ox drawn fresno plow to dig hole
30 cubic. yds. of gravel for the floor drainage system
1 cubic yds of gravel or stone to fill the 2 drain sumps
233 cubic yds of soil will come from the excavation
22 cubic yds of top soil for planting (8” x 66’ x 12’)
94 cubic yds. for the rammed earth walls
This will leave a remainder of 109 cubic yds. for wall berms.
2700 sq’ of plastic sheeting to bury for drainage, if needed
74 ‛ of drain gutter for the lower end of roof
100’ of overthrow/drain pipe from gutter through barrel system to perimeter drainage ditch
116 8” x 4” x 12” adobes for the perimeter to seal plastic roof edge
Interest piqued? Click here for the full instruction with illustrations:
High or low tunnels, greenhouses or garages—hoop houses are handy structures on hobby farms.
By Jim Ruen for Hobby Farms
Photo courtesy Four Season Tools
All hoop houses have steel, PVC or poly-pipe "hoops" that support a flexible cover.
What all of these structures have in common is simplicity of design that uses steel, PVC or poly-pipe to create half-circle or “hoop” supports for a flexible cover. How the hoops are fixed in place and how the cover is secured are all that really differs. Whether covered with plastic or heavy-duty woven fabric, properly tightened and anchored, a hoop house can withstand high winds and a heavy snow load. The hoops themselves can vary from PVC pipe to steel electrical conduit to a range of steel and wood components. Using wood, concrete, gravel or earthen pads, the structures are fast to erect and low in cost compared even to pole barns.
Photo courtesy Farmtek
Hoop houses are particularly valued for their year-round food-production capabilities.
“In my opinion, the hoop house is the No. 1 technology for market and home gardeners, and interest in them is exploding,” says Steve Upson, horticultural consultant for The Samuel Roberts Noble Foundation, a nonprofit agricultural research organization. Since 1995, Upson has been working with, improving on and spreading the word about hoop houses: “They aren’t new, but they are being adopted today at a phenomenal rate. Their use cuts across philosophies of growing, regardless of what inputs you use for managing fertility or disease. Everyone can use hoop houses.”
Year-round gardening expert Eliot Coleman agrees wholeheartedly. He’s been using stationary hoop houses for years to extend his market-garden production and sales season. His high tunnels, when used in conjunction with low tunnels inside, extend his normally short, Maine-seacoast growing season into a year-long endeavor without the need for additional heat production.
“High tunnels have the effect of moving the plants about one and a half [USDA hardiness] zones or 500 miles south,” he says. “Put low tunnels covered with Reemay [polyester fabric] over the plants inside the high tunnels, and we’ve moved the plants another 500 miles south.”
Coleman has modified the concept by placing interior bracing on the hoops, as well as skids or wheels on their bases, to create a movable high tunnel that he can place over an early planting of warm-season crops, like tomatoes, that would normally struggle to mature in the cool Maine summer. As they finish production in mid-October, Coleman moves the hoop house over an August-planted cool-season crop to protect it through the late fall and early winter. As those crops are harvested, beds are replanted with late-winter and early spring cool-season crops. As they mature, the hoop house is again moved to receive summer-crop transplants. The benefits of this system include the ability to rotate in-ground beds for disease control and fertility.
“The real benefit of these movable high tunnels is the flexibility,” says Greg Garbos, president of Four Season Tools. “They just make greenhouse production a different game altogether.”
Garbos has worked with Coleman to commercialize and market the movable hoop-house design. “To be movable, they have to be really rugged and structurally sound,” he explains. “As the unit is moving, you don’t want it to twist, so we add more braces than in a typical high tunnel.”
Introduced in 2009, the structures are available in a 16- by 24-foot gardener size and larger sizes for market growers. They’re catching on fast, and not just for vegetables. Jeff Bahnck and his wife, Alethea, of Bridport, Vt., have modified a 20- by 48-foot Four Season Tools movable high tunnel for their 500 laying hens. Bahnck built and installed laying boxes, roosts, feeders and waterers—all hung from the hoops and braces of the high tunnel. In the summer, shade cloth over the top and galvanized mesh on the sides protects the hens from predators of all kinds. In the winter, clear poly provides plenty of light and keeps the temperature above freezing. Special bases allow Bahnck to move the high tunnel coop laterally as well as forward and back across the field.
“As soon as the chickens hear the tractor, they all run to the side [of the hoop house] where it is, as they know they are moving to fresh pasture,” he explains.
Bahnck is working on special caster wheels that will make lateral moves easier. Meanwhile, Garbos is developing a turnkey, high-tunnel, Hoop Coop kit with bracing for lateral moves, a watering system and plans for wooden components.
Photo courtesy Four Season Tools
The Bahncks modified a hoop house to act as a chicken tractor by suspending feeders and waterers from the structure's supports.
“We’ve tried different types of plastic and also shade cloth to cool the temperature down in the summer, something that is needed for vegetable production during Oklahoma summers,” he says.
Hanley uses off-the-shelf components to construct his high tunnels. Many of the components come from FarmTek. Barry Goldsher, president of FarmTek, says both the demand for hoop buildings and the options available have grown tremendously.
“The variety of hoop houses and coverings is unbelievable,” says Goldsher. “But with smaller structures, many of the components are the same, whether covered with greenhouse film or fabric. Our customers use them for everything from greenhouses to aquaculture and even as solar-powered kilns for drying wood.”
He advises anyone thinking about buying a hoop house to consider the end use in evaluating the construction materials, whether fabricating the structure yourself or buying a turnkey kit. He notes that high humidity can quickly rust poor-quality steel, even if it’s powder coated. Some steel products, including FarmTek’s Allied Gatorshield structural steel tubing, are galvanized inside and outside to prevent rusting or corrosion.
“To build a structure that will last, you need the right diameter pipes [hoops] and rafters, purlins, connectors and anchors,” says Goldsher. “The cover needs to be attached correctly so it doesn’t blow away or tear. It has to be tight. You can always buy something cheaper, but it doesn’t really pay.”
About the Author: Jim Ruen lives, writes and works with his gardens and tree farm in the Bluff Country of southeastern Minnesota.
This article first appeared in the January/February 2010 Hobby Farms.
On a hot, lazy September day, what better activity to do than build a cold frame out of some extra pieces of wood lying around the tool shed?
A cold frame is a boxed enclosure with a transparent roof. Essentially, it's a mini green house. It allows folks like us to grow plants year-round—our plans with this cold frame will probably have to do with planting and growing kale, as well as other types of lettuce. But of course, cold frames can be used to grow just about anything so long as they're kept sealed during the cooler seasons and don't allow heat to escape into the atmosphere.
|Matt and Kevin nailing together the boards.|
|Preparing to photosynthesize. |
Don't forget to make sure the cold frame works properly and that the transparent piece of the structure completely covers the box before thinking you're finished!
|The finished product!|
|Redwood Neighborhood Association Vice President Jim Stine holds the metal greenhouse arch in place.|
With funds secured from the local not-for-profit Hearts for Youth, the neighborhood group's plan was to build a structure to house seedlings and plants for the community. Local residents interested in participating can sign up to help tend the plants, with all excess produce going to the local food pantry.
At the commissioners' meeting at the fire hall April 10, I presented the idea of the greenhouse being put on that property. The group voted unanimously in favor of providing the host site for the greenhouse.
Here are some shots of the construction (thanks to Rick Lopez for the design, Jim Stine for donating some of the materials, and the Better Farm crew for lending a hand!):
e-mail or call (315) 482-2536. And stay tuned for an upcoming announcement on our planting day!
|Hands in dirt: sure sign of spring.|
First, we went out to the compost heap and shoveled beautiful, black dirt into old plastic bags to use as potting soil. Then we took all our flats out of the greenhouse and set them up on the picnic table:
|Our weekend intern, Shani, at left, and our latest resident, Sue.|
To make labels for the plants, Shani cut up empty plastic water bottles and Susan used a Sharpie to write out the names of the veggies we were planting. Once we pushed the seeds into the dirt, it was out to the greenhouse with the soon-to-be sprouts:
To keep the babies hydrated, we're utilizing rainwater from the catchment system installed last summer:
This week we'll be filling the greenhouse, moving the compost heap, and beginning construction on a new chicken coop for our incoming feathered friends. Spring is upon us!
If you'd like to volunteer with us, e-mail email@example.com.