If you are able to do it, heating a greenhouse is a great way to ensure that you are using your greenhouse to its full potential. Setting up a heater is relatively easy and will enable you to extend your growing season or allow you to grow year-round. By adding a greenhouse heater, you can either protect your favorite plants from extra-cold nights or continue growing all of your favorite vegetables the winter.
Heating a greenhouse will be ineffective if your greenhouse covering is not insulated. Because of this, only Solexx greenhouses or those with twin-walled polycarbonate panels (such as Riga or Sunshine) should be heated. Also, it is best that the greenhouse’s frame is insulated so that heat will not be lost in this manner. If you would like to boost insulation in your greenhouse so that your heating will be more effective, you can line the walls of your greenhouse with bubble wrap.
Finding the Necessary Number of BTUs
Heaters are rated by the number of BTUs (a measurement of heat) that they produce. It is important to pick a heater that has the proper amount of BTUs for your greenhouse; using a heater that produces more BTUs than needed will only waste energy and may cause your greenhouse to overheat. You should consult our heater calculator to find out how many BTUs you need based on the size of your greenhouse, your climate and how warm you want to keep the greenhouse. A min/max thermometer is a great way to monitor the lows in your greenhouse so that you know how much heat you need.
Choosing the Type of Heater
Several types of heaters are available, depending on the required number of BTUs and the desired fuel source. Electric heaters are available, as well as heaters that run on natural gas or propane. Operating costs for each of these options are fairly similar, so it is simply a matter of what you find to be most convenient. If you decide to use one of our natural gas or propane heaters, you have the option between vented and non-vented heaters. Generally, non-vented heaters are used because they are slightly less expensive and are adequate for most greenhouse situations. However, there are some areas that require that only vented heaters are used within structures, so you should check locally before making your decision. Vented heaters are also recommended for greenhouses producing sensitive plants, such as orchids or begonias. You can read more about all of our available heaters here.
Other OptionsIf you’re only looking to keep your greenhouse a little warmer at night, there are a couple non-heater options. The most simple option is to use some ten-gallon buckets filled with water. Paint one side of the bucket black and the other side white, and put a lid on the buckets. Place several of these buckets in your greenhouse, orienting the white sides toward the center. The white portion will help the light energy to reflect throughout the greenhouse, while the black portion will help to absorb heat. This heat will be stored in the water until night, when it will be released. Another option is to add several rabbits to your greenhouse. They will produce heat for the greenhouse while providing natural fertilizer. Of course, this should never be done in extremely hot or cold weather.