What is a Hoop House? It is basically an unheated greenhouse – a tunnel made of polyethylene usually semi-circular, square or elongated in shape. The interior heats up because incoming solar radiation from the sun warms plants, soil, and other things inside the building faster than heat can escape the structure. Air warmed by the heat from hot interior surfaces is retained in the building by the walls.
I have had the privilege of being part of a group of 16 enthusiastic gardeners (some experienced, some novice) over the last year as we learned about the potential to expand our gardening season as well as our gardening knowledge. This opportunity was created through the generosity of the owners of the Hoop House who determined it was no longer required for their use. Our Hoop House creates 1500 square feet of ‘indoor’ gardening space.
The garden has been operated as a collaborative garden – no gardener has an individual allotment. Most of the work gets done in a weekly Friday morning work party. Short meetings are generally a part of the work party as is coffee and a chance to socialize. A couple of half-day planning sessions and pot-lucks have helped to solidify a team with shared goals. The organization is the antithesis of a hierarchical structure and has evolved with virtually no conflict as members have assumed roles over the year.
One of the most important goals is to share food with the community. More than half of the produce, a thousand pounds, has been donated to the Lanark County Food Bank. A second goal is to advance our own gardening knowledge. This has been accomplished in spades as experienced gardeners share their knowledge and we all learn about the tremendous potential in extending our gardening season. A third goal is to document what we are doing so that we can share our experience and knowledge with others. This we are starting to do.
One of the major revelations for me was that the Hoop House quickly cools down over the night until the inside temperatures are the same as the outside temperatures. The rapid build-up of heat on sunny days means that plants will benefit and grow faster but the reality is that without over-night heat in the Hoop House we are limited to plants that can tolerate cold temperatures. A big part of our learning experience is finding out which vegetables are appropriate for the early spring and late fall seasons. This year we were able to plant in mid-March and we expect to be harvesting until at least mid-December. In mid-March we had planted vegetables such as spinach, lettuce, radishes and endive. By early April the radishes and spinach were off and running. So what is growing now? Again it is many of the usual suspects such as endive, bok choi, arugula and spinach.
Some of the very fast growing cold-hardy vegetables such as radishes and cress have been replanted recently and are doing very well.
A couple of leafy vegetables that are little known in North America are really coming into their own as the temperatures cool down.
Claytonia which was planted September 4 made a slow start but is probably the most cold-hardy vegetable grown. Claytonia perfoliata is a rosette-forming plant, growing to a maximum of 40 cm in height, but mature plants can be as small as 1 cm. The common name miner’s lettuce refers to its use by California Gold Rush miners who ate it to get their vitamin C to prevent scurvy. Most commonly it is eaten raw in salads, but it is not quite as delicate as other lettuce. Sometimes it is boiled like spinach which it resembles in taste.
Corn Salad (aka Mache) – (Valerianella locusta) is a European favourite and loves cool weather. It is grown just like spinach and is generally eaten raw as a salad green.