Heating garden soil in spring....black plastic vs. glass?
I thought I might experiment with laying out some black plastic in the planting beds this year to help the soil warm up before Spring planting (toms, peppers, watermelon, etc...), I know alot of folks do this. I know black absorbs heat thus it's better than white plastic. But I was curious about hypothetically putting glass over the planting bed instead. I've got loads of extra windows, shower doors, etc....just lying around that I could lay over top of the area, maybe up a foot or so from the soil on concrete blocks, essentially turning it into a big cold frame I guess to warm the soil.
I know greenhouses and even house window areas can get uncomfortably hot even on cold winter days so I wondered about this method. Any thoughts as to how it would compare to the black plastic or is this just a really lame idea? I know it would also be much more labor intensive than just rolling out plastic but if the soil warmed up considerably more or quicker it might be worth it. Often times our last frost date isn't so much the deciding factor for planting as much as the soil temps. After danger of frost has past, my tomatoes always seem to limp along for a long while in the Spring until the soil gets nice and toasty.