Greenhouse Heat 101:

Found on this page are all of the key necessities needed in Greenhouse Heat.

However we wanted to include these links as well:Heat a Greenhouse - diving in a little deeper - Video with great music too :)

Greenhouse Air Circulation - Micro Climates.

Greenhouse Temperature - Temperature Classifications: Cold, Warm, Hothouse (and the temps. that go with them).

Greenhouse Thermometer - a needed tool for any greenhouse.

Greenhouse Ventilation

Solar heat is a big portion of any greenhouse heat; however, for year round production added heat is often needed. Of course the plant zone that you are located in plays a role as well.

There is almost always a certain period of time throughout the year that supplemental greenhouse heat will be needed.

This depends on the type of plants that are being grown as well – some trees need a cold period of time so that they can go dormant, some need this period of dormancy to survive, most of my bonsai need a period of cold like this but are protected by using a non heated hoop house .

However, if growing fruits and vegetables supplemental heat will be needed, if not always used, it’s nice to have the backup just in case.

Greenhouse Air Leaks:

With any greenhouse heating, the goal is to replace the heat at the same rate that it leaves the greenhouse. So the key to greenhouse heat is to make sure that the greenhouse heat doesn’t leave.

Find where the heat is lost in the greenhouse, and seal the draft. A good way to do this is to find the micro climates , when those are found there could be a draft.

As mentioned, solar heatplays a big role in heating a greenhouse. It’s important to retain the sun’s heat because it’s free! To do that the greenhouse requires something that can be used to store the heat.

At night the stored heat emanates back through the greenhouse, radiating the warmth that was stored in the form of long waves, which do not readily penetrate the greenhouse covering.

The greenhouse should be made as airtight as possible, but even in a tightly sealed greenhouse, heat is lost through the glazing material.

    The Top Ways that a greenhouse looses heat:
  • Broken panels
  • loose panels
  • poorly sealed doors, and other openings
  • Improperly installed vents
Any loose seals in the greenhouse increases air flow, and increases heat loss. The quickest Way to cut this loss is to seal the leaks.

Install double or triple glazing, line the interior with inflated layers of polyethylene plastic , or use insulating greenhouse curtains that roll down the inside of the glazing at night.

The Key to Proper Greenhouse Heating:

The key to properly heating any greenhouse is to match the appropriate heat for the plant that is growing in the greenhouse.

This is why not every type of plant can be grown in any one greenhouse. Growing any plant in an environment that it is not accustomed to is just asking for an unhealthy plant. If the temperature is not right, it won’t be able to grow as vigorous as it would in the proper conditions.

Air Circulation:

It is also important to have good air circulation as well, to assure an even distribution of the heat, eliminating hot and cold spots.

The north wall of the greenhouse provides a quick escape for heat. It is the side of the greenhouse that receives the least amount of light and is usually the side that is used to stack heat sink material like jugs of water, and black barrels full of water to create thermal masses to hold heat.

At night, this heat radiates out and keeps the greenhouse warm. If you have an attached greenhouse, cover the back wall, with bricks, anything with a dense material acts as a great holder of heat (but not as good as water). For a really good video description of Solar heat visit our Solar Greenhouse page.

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