Photo by Axel Kristinsson from Reykjavík, Iceland
Winter greenhouse! Photo by Axel Kristinsson from Reykjavík, Iceland

The advantages of having a greenhouse are obvious when it’s cold outside. Winter greenhouses extend the growing season for farmers and gardeners alike, creating the opportunity for a larger overall harvest.

How it works is fairly simple: The sun warms the air, plants and soil during the day, and then the greenhouse traps some of that heat and protects its interior from dropping night temperatures. The greenhouse must be sealed, however, for that work. Only ventilation fans and intakes can be sources for fresh air. With supplemental lighting and some heat, a “‘controlled” environment is now achievable.

A controlled environment is one in which outside factors like temperature extremes, dry conditions or long periods of darkness are not allowed to adversely affect crops growing within it — all these factors are set and controlled by the cultivator. But the grower must create and maintain an environment that nurtures plants completely—just because the air temperature feels right doesn’t mean the soil or water temperature is actually ideal for the plants.

Optimal Lighting and Heating Options for Winter Greenhouses

Adding lights and above-air heat can actually result in a decrease in production of up to 40%. When supplemental lighting and root zone heating are added to the mix, however, these problems disappear. Ambient air temperature should not be your main focus. Whether soil or soil-less gardening is your thing, root zone temperature plays a huge factor in determining the end result. Find a way to warm up the water or get a radiant flooring system if you want to increase crop production in your greenhouse in the winter months.


Featured Photo by Axel Kristinsson from Reykjavík, Iceland. Via Wikimedia Commons under Creative Commons license.


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