Why did the Glastonbury Prosperity Association (GPA) decide on a greenhouse as its first demonstration project? To be a successful gardener or grower in the extreme climate of Montana, a greenhouse is a necessity. The greenhouse serves as a big lever by greatly increasing the length of the very short growing season here.
The growing season here in the Paradise Valley is so short that only the hardiest crops will make it through to maturity before a killing frost. A greenhouse can help extend the growing season enough so that sensitive crops such as squash, pumpkins, cucumbers, peppers and tomatoes can survive until fruit is mature. Even in mid-summer, the temperatures at night can be low enough to delay the maturity of many crops.
Large and Small “Greenhouses”
Dozens of designs of various sizes and shapes have been developed for sheltering crops. Sizes vary from plastic milk cartons on up to football size greenhouses. No one best design exists for every crop in every environment. For a small gardener, a cloche made from a milk carton will work to shelter a single tomato plant. A cold frame made from an old window can shelter several plants. On the other hand, a commercial grower will need a full scale greenhouse to shelter many beds of plants.
Lean-to Greenhouses
Gardeners with large southern exposures on their houses or out buildings can put up a lean-to greenhouse or sunroom. This type of structure will not only serve to shelter plants but also serve to cut down the heating bill. The lean-to can act as a passive solar heat collector. If the doors and/or windows are opened between the lean-to and the main structure during the heat of the day, the utility bill will be significantly reduced.
We chose a geothermal style greenhouse in order to cut down the heating and cooling requirements. At about five feet below ground level, the temperature stays constant year around in the 50s F.
We dug a pit about five feet deep and poured a foundation about fifty by twenty-six feet in dimensions. Later we poured concrete walls on top of the foundation to give a total depth of about five feet.
During the late summer and early fall of 2016, we put up most of the superstructure for the greenhouse. By the time snow started falling and it became too difficult to work outside, we had most of the superstructure in.
In March, when the weather warmed up sufficiently and the winds were not too strong, transparent double paned polycarbonate panels were attached on the south side. A few days later, we put up the remaining panels on the sides, and put plywood on areas where windows and doors are to go.
As soon as we raise enough money, we will put in windows, siding, more insulation, a stairway, solar panels and water storage tanks. We plan to have a work party soon and install the beds inside the greenhouse.
Fundraising for Greenhouse
We have been holding monthly fundraising events to help raise the money needed to complete the greenhouse. For the past four years, we have held very successful fundraisers at the Lighthouse Restaurant after the Freedom Conference and before or after Summit University. We plan to have our fifth fundraiser there this summer. The theme has not been determined yet.
So far, we have raised over $30,000 and plan to raise another $10,000 or so to finish off the greenhouse and landscaping. If approved, we have enough land that we could start a food forest around the Greenhouse. This food forest could significantly bolster food security for the community. If you would like to donate, you can use the “Donate” button on this website. Thanks to all those who have donated time, talent and supply to this project which should increase our chances of surviving a cataclysm.
Hoophouses
On a personal level for the home gardener, greenhouses can be purchased for much lower prices. However, if one lives in a very windy area and/or an area with heavy snow, the cheaper models will need to re-enforced to withstand the extra stress.
Hoophouse greenhouses in the shape of a Quonset hut are relatively inexpensive to construct but require more maintenance than our type since the flexible plastic has to be replaced every four to six years. On the other hand, the double paned rigid polycarbonate which we used should last for many more years.
Cattle Panel Hoophouse
One of the cleverest and least expensive designs for a hoophouse style greenhouse was developed by a Youtuber with the moniker of Texasprepper2. This style incorporates cattle panels (about $20 each) as the basic building unit. The panels are fifty inches wide by sixteen feet long. The metal bars used in the mesh for the cattle panel are much stronger than normal fencing but are still flexible enough to be bent into an arch about seven feet high and eight feet wide at the base. Separate cattle panel arches can be attached together with wire or other fastener or welder. The greenhouse can be made as long as possible depending on how many cattle panel arches are attached side by side.
Two by six planks can be added to the bottoms of the arches to hold them in place. You can see the original design and the many variations that have been developed by Texasprepper2 and others by doing a search of Youtube.
Harbor Freight Greenhouse
For someone wanting a greenhouse with panels that do not have to be replaced frequently, Harbor Freight makes the least expensive that I could find. They have two sizes: six by eight ($200) and ten by twelve ($500 to 600). To get these prices, one needs to buy them on sale and use the 20% coupons on their sales fliers. There are several Youtubes showing how to modify these greenhouse to make them more sturdy to withstand high winds and other stresses.
Greenhouses are not only valuable for growing produce, but also for helping maintain sanity in long cold winters. Nothing can lift the spirit more on a bitter cold winter day than a trip to a balmy greenhouse.
Happy greenhousing!