The more money one is willing to spend on automation , the more effectively one can maintain an ideal atmospheric equilibrium .”
wintertime greenhouse gardening
The more money one is willing to spend on automation , the more effectively one can maintain an ideal atmospheric equilibrium .”
HEAT SOURCES AND SUPPLEMENTAL LIGHTING
When planning a wintertime cultivation operation , it ’ s crucial to understand that controlling a constant greenhouse temperature is extremely difficult . Again , the more money one is willing to spend on automation , the more effectively one can maintain an ideal atmospheric equilibrium . With a wellinsulated greenhouse , wintertime cultivators must balance climactic requirements with both heating methods and supplemental lighting . In the design of a greenhouse heating system , gardeners need to weigh both ambient temperature and root-zone temperature against the demands of their desired crop . In geographical locations where temperatures are cold enough to freeze the ground , keeping root zones warm is an essential practice . Root zones can be protected by growing in raised beds off the ground , using heating mats beneath pots , and running hot water in tubing beneath pots . Finally , ambient temperature in a greenhouse can be controlled with a variety of methods which are dependent upon greenhouse size , outdoor climate , and budget . These can range from a simple electrical space heater for your novice operation to thermostat controlled , industrial propane heat sources for a large-scale operation . For cultivators interested in growing light-intensive crops in the midst of winter , supplemental lighting is a must . Generally speaking , HPS ( high pressure sodium ) and DE ( double ended ) lights are utilized in wintertime greenhouse gardens to supplement sunlight on cloudy days and to extend growth periods on short winter days . Supplemental greenhouse lighting has two serious implications for the wintertime gardener . To begin with , HPS and DE lights emit a large amount of heat — this heat must be balanced with the ambient temperature in the greenhouse during both day and night . Secondly , these lights are expensive to operate and should be utilized under consideration of a cost / benefit ratio . For growers in northern states , this ratio makes it obvious that it ’ s less practical to grow light-intensive plants in greenhouses than indoors during the winter . For horticulturalists in warm and temperate climates , however , wintertime greenhouses are economically viable . To further illustrate the challenges and benefits of wintertime growing in a temperate climate , I asked Matt Johnson , a northern California greenhouse expert , for some detailed advice .
MAXIMUM YIELD : Is expensive automation a necessity in wintertime greenhouse cultivation ?
MATT : That ’ s totally dependent upon your goals and lifestyle . If you have an industrial-size grow operation , it ’ s a must . Otherwise , it ’ s going to be a really hands-on experience 24 / 7 .
MY : How do you deal with the extreme temperature fluctuations of greenhouse growing ?
MATT : I have an industrial propane greenhouse heating system , which is run by a thermostat . This is used in conjunction with industrial dehumidifiers so that we exhaust the greenhouse as little as possible . In this way , the exhaust system doesn ’ t pull in cold air from outside and push out the warm air from the heating system .
128 Maximum Yield USA | February 2017