Frozen water in 2-litre jugs can help tomatoes to set fruit in the extreme heat of the deep South.
Tomatoes grow well throughout the winter in Florida. By late spring, though, it’s too hot to get the fruit to set. I thought a bit and came up with a solution: frozen water in 2-liter soda bottles.
If I’m having trouble getting the fruit to set as the weather gets warmer, I simply put a plastic tent over the plant at night, and under the plastic tent I place the ice-filled bottles. This setup takes the air temperature down enough to allow the fruit to set on the tomato plants, and it works very well.
Palm Harbor, Florida