Coldframes Manhattan, New York
At the beginning of the 1900s, many modern cities were growing vegetables under glass during the winter months. Truck farmers in these cities, including Manhattan in the USA, and Paris in France, were able to grow significant amounts of food in simple cold frames. I’ve heard stories that some New England states were even shipping fresh winter vegetables to Florida during this period!
Cold frame growing and other greenhouse growing techniques have taken great leaps since those early days. Elliot Coleman has brought season extension to a new level and is the leading expert for small and medium scale cold weather organic vegetable production. Growing under glass has exploded into the industrial realm as well. In some regions of the world, large scale greenhouse farming is so large you can see it from space!
View of Spanish greenhouses from space
The preferred material for many present day greenhouse systems is clear polyethylene plastic film. Cheap, easily shipped, and simple to install, plastic film can be purchased through regional greenhouse supply distributors. Unfortunately even the best thin film is only built to last 6 years. That is a lot of plastic going to landfills! Not a very ecological material to be using…. Yet, I would say it depends.
What if we were to compare the plastic used to grow industrial scale tomatoes with plastic covering a structure that is more ecologically built, for growing food in more ecological ways? Could the use of plastic film on the ecological structure be a better use, in terms of calories collected, and life sustained, then if it was used in a more conventional way? One such ecological structure, a bioshelter, is a passive solar greenhouse that captures the sun’s energy, using it in as many ways as possible to maximize productivity.
Holyoke Edible Forest Garden Bioshelter
In Holyoke, Massachusetts, USA, we have built such a structure. Our bioshelter design was inspired by the early work done at the New Alchemy Institute decades ago, and greenhouses built by Steve Breyer at Tripple Brook Farm. Our bioshelter’s internal systems are a compilation of old and new technologies and techniques. And its low cost construction is almost entirely made up of reclaimed or recycled materials.
The 400 square foot building’s mechanical systems are powered with a solar panel, and it is kept warm by the sun and earth. Inside we grow hardy vegetables, subtropical fruits, aquatic greens, fish, fresh water clams, crayfish, compost earthworms, and soldier fly maggots (the worms and maggots are fish food).
Holyoke has an outside plant hardiness zone of 6, the bioshelter is designed to keep warm enough to mimic a northern Florida winter, zone 9. The 2012/2013 winter will be our first cold season. So far we’ve had the temperature drop to negative four degrees fahrenheit outside, while the bioshelter has stayed warm enough, 30 degrees F, to overwinter a hardy avocado.
Building the bioshelter was an amazing experience, and living with it has been even more mind blowing. We’ve been eating delicious bioshelter grown greens in our meals all winter long. Flying south for the winter hasn’t even crossed our minds.
We are excited to be offering our second year of bioshelter workshops. If you would like to learn more about this inspiring ecological project please be in touch with us. We’d love to have you for a tour some time! Find Jonathan Bates at PermacultureGreenhouse.com