greenhouse is northern Texas
 

Ron, you've been a great help and we are getting ready to build a permanent greenhouse is northern Texas. I have read your sight and now have a question about how to control the temperature here when it reaches 100+ - do I understand that since I have a low dewpoint (less than 60) that I cannot use a swamp cooler and must use and air conditioner? if so, what size to you recommend of a 12 x 14 greenhouse that will get a lot of shade, but the temps are high - thx novice

Here in florida most greenhouses have to shut down the hottest months and use that time to clean the greenhouse and all the equipment for the next growing season. Some growers switch to plants that can tolerate higher heat like ornamentals and most herbs and spices. To cool it with an air conditioner it would have to be a big one because you would ware out a window model fast.