Last spring/summer I built a greenhouse and grew some tomatoes and a few other things in it. I had a real problem with humidity. On sunny days, it wasnít an issue. The greenhouse would get hot enough that I needed to ventilate for temperature control, which keep the humidity in check. However, on extended cloudy periods, I didnít want to lose heat and kept things shut and that caused the humidity to go way up. It got so bad that a fungus blew through the tomatoes destroying a lot of green and tomatoes.
I want to prevent that this year. So, my question is, how do you keep the humidity levels down without losing a lot of heat? I really donít want to pay for supplemental heat in the greenhouse during the summer months when we have an extended cloudy period.