Q.How To Solarize Garden Areas
You have conflicting information regarding solarizing flower beds. One page says: You can also solarize beds by spreading black plastic over an area in full sun for a month to kill the fungus. https://www.gardeningknowhow.com/plant-problems/disease/controlling-fusarium-wilt.htm Another page says: Only clear plastic be used to solarize garden areas. Clear plastic allows sunlight to pass through more easily, which is vital for soil heat retention. Black plastic does not sufficiently heat the soil. https://www.gardeningknowhow.com/garden-how-to/projects/how-to-solarize-garden-beds-to-eliminate-garden-pests-in-the-soil.htm So, which one is it? Clear or black?
Certified GKH Gardening Expert
Really, clear is better. I have used black in the past for pasteurization, but it will not kill persistent fungi. If you need to kill off something like Phytopthora, then clear will be your best bet.