• Kelly Grummons

How can we make better use of a greenhouse?

Q: We got a neat, little 6 ft x 8 ft greenhouse about 3 years ago for growing vegetables through the winter and for starting garden plants in the spring. So far, it’s been mostly a disaster and waste of time and money. It gets too hot in there, too cold, too buggy, and a myriad of other problems. How can we make better use of the greenhouse?

A: Keep in mind, the smaller the greenhouse, the more difficult it will be to manage the high and low temperatures. 6 ft x 8 ft is a very small greenhouse. I would recommend a minimum of 8 ft x 16 ft building not only for easier climate control but also big enough to grow a practical amount of produce and/or transplants. Every small greenhouse will need a small electric heater with a built-in thermostat (1500 Watts is adequate for most small greenhouses), a small to medium swamp cooler plugged into or wired into a thermostat and a High/Low thermometer to monitor your temperatures throughout the day and night. Adjust your heater and cooler to achieve a goal of cooler than 85 degrees F during the day and 55 degrees during the night for warm crops (tomato, pepper, eggplant, green bean, cucumber) and 75 degrees F during the day and 45 degrees during the night for cool crops (pea, fava, radish, lettuce, spinach). Once you have the climate under automatic control your productivity will increase dramatically and your pest and disease problems will moderate.


Written by Kelly Grummons, who writes our Q & A column, is co-owner of the mail order nursery businesses, coldhardycactus.com and dogtuffgrass.com