I have a large container that I grow tomatoes in every year, placed underneath my second floor patio, so it stays somewhat out of the rain. This past year I left my tomatoes on the plant a long time, waiting for them to ripen. It was getting quite cool at night before I brought them all in. Some of the tomatoes had spots on them, and I don't know if it was from the cool air, or if my tomatoes had blight. Is there anyway I can safely reuse the soil in the container? I'd prefer not to have to throw it out, it is a large amount, and I'm not sure if it was blight.