Year-Round Food Production: So Much More Than a Greenhouse

For anyone eating on a budget, or living in a food desert where it is difficult to get to the grocery store, protein and fresh vegetables become luxuries. Without protein and fresh vegetables human health is compromised. Access is particularly limited where fresh vegetables cannot be grown outdoors during the winter. Carbohydrates like beans, rice, potatoes and pastas come cheap in bulk and store easily but animal protein and vegetables are best eaten fresh. A greenhouse is an option for winter vegetables but any savings can be lost if you have to heat the greenhouse.

We are developing ways to address these issues by designing for a relatively inexpensive structure that can be attached to the south side of a building to produce protein and fresh vegetables year round. To avoid the expense of gas or electric heat we are enclosing enough thermal mass to absorb extra heat when the sun is shining and release it when the sun goes down. The formula from the passive-solar greenhouse literature is that we need between 2 and 5 gallons of water, or equivalent, (masonry gives you about ¼ of the heat storage as the same volume of water) for every square foot of glazing. It also turns out that the type of glazing is less important than how well we are able to seal the structure against air leaks. We also get credit if the wall to which we attach the structure is heated from the other side.

We are not purists so we do not mind adding “active” elements to the system and we like to have each element serve multiple purposes. We like to try things and see how they work. Also, this structure is a part of our wider explorations into how we can work with nature and use natural processes to reduce our work load.