For a while now i've been looking at adding covers to my raised beds so I can get the spring stuff in the ground due to the short spring we get around here. ( it can freeze untill may and 90-100's by the middle to end of june) I would like to get my lettuce and cabbage started. While there is many differnt articals that out line this they leave me with a few questions. 1. if you cover completly, is there a problem with the plastic sweating? do you need to vent it? 2. how to afix them to your frame? I still will be getting 20-30mph winds here. any thought from those who use them?