I planning on building me some raised beds and start gardening with this style and I also want to build a cold frame so I can get an earlier start. So what I'm thinking of doing is to build my raised beds with some type of lumber, approximately 3 ft. wide by 15 ft long, fill with soil, and then also build a hoop house over these beds using pvc and plastic. Each bed would be for tomatos, cucumbers, squash, maybe watermelons and cantalopes. These veggies mentioned I have a hard time with once the summer heat drought starts. In my creek bottom the last frost isn't until about the last few days of April or the first few days of May. I set my plants out as soon as I think it is safe enough from the frost. They grow real good and have lots of fruit on them. But it seems I only get one good picking off of them and then the summer heat drought hits (usually soon after the 1st of July) and starts scourching everything. My tomatos will scald on top, squash will harden on top, cukes scald on top, and my watermelons and cantalopes become stunted. So my question is how much earlier could I transplant if I had a cold frame over my raised beds? Also I figured if I leave the hoop frame in place after its warm enough to remove the plastic then I could use some type of a shade cloth to keep my plants producing longer when the sweltering 100 plus temperature arrive.