I do not have a greenhouse, don't think I'll ever have one due to the limbs that constantly fall in the backyard. However, I do like to play and experiment. I bought a TON of plastic paint tarps used as drop cloths a number of years back. The idea was to cover raised beds in the late winter to help warm up the soil. That didn't work. So this last fall I actually was way ahead on maintenance and threw a couple of the plastic tarps over a couple beds supported by bamboo poles that had an upside down container on it so the pole didn't puncture a hole in the plastic. Looked GREAT! not, but looks aren't important to me. Whenever I made it out to the garden I'd check the temperature, by hand literally. I compared a bed that had the same 3" of shredded leaves to a bed that was covered in plastic. SHOCK. The air temperature wasn't really different, but the soil temperature was. The uncovered bed had ice at times in the upper inch of shredded leaves. The soil below that was also COLD. Under the plastic ice never formed and while not warm, my hand preferred being in the soil under the plastic.
Then the first snow of the season fell last week. LOL. Only the plastic of one of the three beds is still covering the bed. It'll be interesting to see the results in a couple months. I did start buying row covers with fleece so I will have supports next year. I might get some what is it 6mil plastic for the next attempt. Not really trying to grow anything under them... just would like to see some worm activity, and warmer soil earlier.
