We have had lots of problems with our new greenhouse. Forty mph winds (typical for spring at One Love Farm) caused the plastic skin of the greenhouse to come loose on several occasions. In addition, the constant movement of the plastic caused rips in the skin at the pressure points (especially where the clamps affixed to the poles).
I made several attempts to correct this issue. First, I extended the length of the greenhouse. This allowed the hoops to be flush agains the 4x4 clothes line base. Since these 4x4s were in concrete, they didn't move at all.
Next, I used PVC cement to reinforce the joints of the PVC piping used for the hoops. When these joints came loose, they would pop through the skin of the greenhouse and rip the film.
Unfortunately, these measures only helped marginally due to fact that the greenhouse was now 30 feet long and the longest availble 4mil plastic is 25 feet long. I tried using weather seal tape reinfored with duct tape to add the extra 10 feet. However, during a particularly windy day last weekend, the seal failed and skin was again flapping in the wind.
Finally, I decided to upgrade to 6mil clear greenhouse quaility plastic for the skin. This should have been done from the beginning. It is so much heavier and stronger than 4 mil. I also weighed down the film on the side with about 50 cinder blocks and bricks to prevent the wind from moving the plastic. Finally, I am attaching the plastic on the inside of the greenhouse with velcro and not clips.
This seems to have worked well. Today, there is a breeze and the plastic is not moving. Also, the temerature inside the greenhouse is over 100 degrees F! With the 4 mil, the temp rarely got to 70. However, the real test will come Tuesday, when the spring winds return.
