We finally decided to do something about the weather after all, build more greenhouses! We have experimented this year with an A-frame greenhouse that we built ourselves and are very impressed with the results.
We have tried using hoop houses in the past that are made out of tubing and covered with poly plastic green house cover but they have not held up well in our windy location. (French Garden Farm is on a ridge and is very windy much of the year, so much so that we are now thinking of installing wind generators!)
With the A-frames that we built, we can orient them to the south-west, which is where most of our wind comes from and get the best solar gain as well. The wind then has the effect of pushing them into the ground rather than trying to lift them up. An added benefit is that the beds on the leeward side of these greenhouses are protected from the wind as well making them a little warmer.
Each A-frame is made of 10′ x 10′ panels that are screwed together and staked into the ground with concrete form stakes. We leave the ends open in the summer so that pollinators and beneficial insects can find their way inside and the greenhouse doesn’t overheat. We can also tilt open sections in the middle if it is a particularly hot day.
The results so far are VERY impressive! Primarily we have grown peppers and cucumbers, but also some tomatoes. It is clear from comparing our field plants to the ones in the greenhouse that we should do much more growing in this way.
It costs about a dollar a square foot to build these greenhouses and we expect that the poly will last 4-5 years. We hope the wood frames will hold up longer, but we have used Douglas Fir, which may rot where it touches the ground. Assuming that the lifetime costs are about 15 cents per square foot a year and the possibility to raise 3 crops a year, these greenhouses look like a very good investment with a cost of about 5 cents per square foot per crop.
To date, it looks like the yield on warm weather crops will be 2-4 times greater than those grown outside, a huge benefit. This winter, we will see what we can grow inside as well. I expect we will see similar results.
