Greenhouse Conditions
Greenhouse Climates

The following greenhouse characterizations are based on the temperature that can be maintained inside the greenhouse. They range from the least to the most expensive to build and maintain.

Refer to this information when reviewing what you want to grow in your greenhouse.

Cold greenhouse - A cold greenhouse, the least expensive to maintain, is a freestanding structure that is heated by the sun only. If you're in a cold-winter area, the inside greenhouse temperature may be only 10 degrees above the outside temperature. This type of greenhouse is typically used to start or house seedlings in late winter or spring (three to four weeks ahead of outside planting time). It can also be used through the summer and into early fall to grow selected plants. In an area with cold winters, it might be used for overwintering semi-hardy outdoor plants, but more commonly would be shut down.

Cool greenhouse - This type of greenhouse can maintain a minimum temperature of 42 to 45° F. In cold-weather areas, such a greenhouse would be heated during winter months. It can be used to overwinter frost-sensitive plants, to start plants three to four weeks ahead of the cold greenhouse, to raise warm-season crops through the summer, and to grow some cool-weather crops into the fall and winter. It might also be used year-round as a conservatory for desert plants.

Warm greenhouse - This type of greenhouse can maintain a minimum temperature of 55° F, with additional heat during the day and night, as needed, depending on its location. It can be used through the year for a range of growing projects, with heating expenses rising as winter temperatures drop. It provides good conditions for growing vegetables and many annuals to maturity and for conducting a wide range of research projects throughout the school year.

Hot greenhouse - This type of greenhouse, the most expensive to maintain, sustains a minimum temperature of 65° F with additional heat throughout the year. While too warm for many vegetable plants, it can be used for raising subtropical and tropical plants.

Seasonal Sun

 

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