Are they worth it? I'm getting to the point where my little greenhouse at home is full along with the window sills in the house and I still have stuff to start off indoors. I've got a greenhouse on my lottie but I won't have time to go down there twice a day to open and close the doors - I can go down inthe evenings to water. I'm concidering gettint two vents one for each side of the greenhouse. Would this keep the temperature down enough or should I just get up earlier and go twice every day?