I am experimenting with solarizing soil. Although my purpose is to rid it of Oxalis pes-caprae, it would also sterilize for other purposes. My purpose requires 135 F for 2 hours. Not all days are sunny enough to reach that. Here is a photo of my setup: http://flickr.com/photos/gastils_garden/… It is small scale. I can do 5 buckets of soil each sunny day. It takes a lot of effort to fill the bags and secure the plastic outer bag. I have two other solarizing experiments in progress but they do not reach as high temperature. I'll report late this winter whether the O. pes-caprae was successfully eradicated. - Gastil