Dave, I have a few more questions....
I have a raised bed (3 high cement block frame), that gets sun all day long. (south and north exposure). Going by the dates that turn out to be incorrect, I was planning on planting corn, bush cukes, okra and muskmelons in it. If I put a "greenhouse" over the bed (pvc hoop and plastic), do you think I could entice these warm weather crops to grow before frost (typically around October 19)? Thank you! Jackie