This will be my first year of operating the greenhouse and I could not be more excited. In the past I have used window sills, hot lights, absolutely nothing, bought starts, or just did not have a garden; this year is going to be different.
One of the added bonuses of this Farm was that it came with a functioning greenhouse that faces directly south. It came equipped with an exhaust fan and heater but both needed attention to make the system more automated for when I am not around. The framing of the space was done in 2x4's and paned glass, the roof is built of corrugated plastic to add insolation. Last year I recorded temperatures in the mid to high hundreds, at times it is similar to a sauna so I am confident with some adjustments that it will be an adequate hothouse.
When I first started, March 27, 2011, the temperatures were barely dipping below zero and I felt that with minimal energy the heater could sustain 60+ degrees through the night; I was wrong. Spokane has an uncanny ability of tricking people, this is to say when an avid gardener says 'do not plant until Mother Day' don't plant until Mothers Day; period. It snowed the night I planted, something like 1/4 of an inch.
In a moment of clarity and frugalness I stapled a clear plastic drop cloth to the north wall of the building and draped it over a seeding table with the heater directly beneath. This created a microclimate that allowed me to adjust the humidity and the heat to a perfect 80 degrees using 1/8 of the energy. I am seeing great results from this system and intend on modifying it for next year to include a larger space and a better watering system.
With 180 starts at various stages of germination and growth it looks like this year is going to be amazing. I think that starting this early could have been jumping the gun a bit much but it has allowed me time to make mistakes and to modify.