|High Tunnel with sides raised|
The great news was with temps seldom above 82 F in the summer lettuce and spinach did not bolt. I dreamed of an attached green house that would provide passive solar for winter months and allow me to get a start on plants to go outside in June. As I planned the green house grew and when construction began in 2007 the beds had to be moved. Long establish herbs like Tarragon had to be moved and did not survive their temporary containers. Despite efforts there was no gardening in 2007 or 2008. Two 4 x 4 beds just didn't seem to produce and last freezes seemed to have moved to the middle of June.
|Low tunnel with sides up and beginning of high tunnel supports|
This April I decided to give it one last go. I up and moved the beds so I could put a tunnel over them. The low tunnel worked fantastically. Plants were protected from late freezes (well, early freezes because I planted a full two weeks early). And with the night cover and day protection when the weather was foul the lettuce and assorted greens just grew faster. I decided to go ahead with the high tunnel.
As Youtube videos, articles, and my friend in Utah explained, the low tunnel could raise the temp four degrees and the high tunnel over the low another four for an eight degree gain. More importantly it seems combined with the raised beds the ground temps are raised. Tomatoes want 55 F ground temperature.
|Side ribs up|
|Center pole and end ribs up. Almost time for plastic|
|S hooks at base of ribs for tie downs|
|Detail of roping over high tunnel|
During the high desert cool nights the low tunnel plastic can be pulled over the beds and the high tunnel plastic put down. In the bow ends I have another raised small bed with tomatoes and a couple container gardens of squash. This year these are experiments. Between the two raised beds I have potatoes which are suppose to be a cold weather crop but their leaves were very easily damaged by our late frosts. My last couple years of gardening were just lettuce, greens, carrots, garlic and onions.
An extra bonus with the tunnels has been protection from spring winds and hail of our summer thunderstorms. More than one lush bed of lettuce has been shredded by hail. When I first tuned into the polytunnels being used on farms I figured it was a spring and fall thing. Supposedly you can extend your growing season two weeks either side. A hard fought for 90 days to 130 is well worth raising and lowering plastic morning and night.
But the tunnels cut down on watering and also seem to make plants grow bigger and faster. That is probably due to the warmer soil. I try to cover up before the temps of the day fall off, holding in the warmth.