Super Greenhouses

(New Alchemy, Prince Edward Island 1976)
The last blog but one, on 8th March, I raised the question of how to feed humanity in radically more sustainable ways, and set out some of the criteria I think will be important to the future of farming. In the next couple of blogs I want explore how to grow a wide variety of fruit and vegetables year round in cold climates. Protected cultivation in greenhouses and polytunnels is important, but currently commercial production often involves additional fossil-fuel derived heating, which often has a worse ecological footprint than air-freighted produce. We can do better. By adding thermal mass to the greenhouse we can even out the day to night temperature fluctuations and so reduce or eliminate heating. In my greenhouse here in Hereford I have a vast range of produce growing with tomatoes already a foot high. I use stacks of bricks to absorb heat in the day and to act like storage heaters giving off their heat at night and so protecting my crops from frost. I also use a small plastic greenhouse within a greenhouse, and sheets of bubble wrap to protect the most vulnerable crops. Others though have taken this concept very much further than I.
The New Alchemy Institute was founded in 1969 and wound up in 1991. At its zenith in 1976 it built two extraordinary greenhouses, one in Cape Cod, Massachusetts and the other on Prince Edward Island, Canada. The Institute was founded as a research project by John Todd, Nancy Jack Todd, and William McLarney, to study and design radically more ecologically sustainable ways of living. The greenhouses, bio-shelters, or arks as they called them, were experimental structures designed as living spaces and to produce food year round in cold climates including a wide variety of fruit and vegetables and also fish. Having large fish tanks in the greenhouses added thermal mass and so evened out the temperature fluctuations between day and night. They also generated on-site electricity with wind-turbines and photovoltaics, which in the mid-70s was pretty ground breaking, and they collected rainwater and recycled sewage. Their aim was to minimize waste and to free themselves from fossil fuel dependence. In 1976 they were an inspiration for me. I wanted to visit them but failed to get an American visa. The project was grant-funded academic research, and folded once the grants dried up.
For more about the New Alchemy Institute see, “A Safe and Sustainable World: The Promise of Ecological Design.” Nancy Jack Todd. Island Press. 2005