Greenhouse Heating Methods

How The Big Guys Do It:

Greenhouses can be heated with various methods. Heat control for commercial greenhouses typically use propane gas. The heater provides the commercial facility with multiple purposes; as the propane burns to create heat, it also releases CO2 which is a source of plant food. Propane is generally the most accessible fuel source to obtain in most areas.

Forced Air Heater Drawbacks:

Forced air propane heaters are the least expensive way to heat a greenhouse, but since they are unvented they will create humidity inside your facility. Another downside to inexpensive propane heaters is that the light from the open flame is not contained thus causing potential problems inside of your garden.

Value Based Choice:

There are higher end propane models that use tubular heat exchangers which contain the light from the heat source, also acting as a conductor of heat. A fan mounted behind these tubes blows through the tubes pushing hot air into the greenhouse. These heaters are also vented which helps keep the humidity levels from spiking during operation.

Other Options:

Electric heaters, while having an easy source of energy, require a significant amount of power to operate and are generally not nearly as efficient. Radiant floor systems have been gaining popularity in the greenhouse world for their extreme efficiency. The process uses piping that is run through a mass designed to retain heat, generally either compacted sand and gravel or cement. Inside of the piping a hot water and glycol solution is ran through the system causing the mass to store heat and radiate through the plants inside of the greenhouse creating an even heat distribution in the facility. For more information on radiant flood systems please submit an inquiry here or call us at (541)480-9392.

Heat vs Humidity

Keeping Humidity Levels Even:

Effectively heating a greenhouse is a battle every farmer faces towards the end of the season. The battle between controlling heat and maintaining normal humidity levels becomes a constant struggle for most greenhouse cultivators. When a greenhouse cools and heat is needed to be added, a clash of warm and cold air creates undesirable humidity. As the greenhouse warms up, humidity will increase due to warm air having a higher capability of holding water. The best way to maintain heat in a greenhouse without increasing humidity is by preventing the greenhouse from dropping in temperature.

Other techniques of maintaining heat and keeping humidity average is by “burping the greenhouse,” the process of quickly exchanging the air in the greenhouse by using either a passive system such as roll up sides or a forced air ventilation system like exhaust fans and intake shutters.

Plant Health & Heat

Cannabis as a plant is a very hearty species that can endure a wide range of temperatures, however it is not ideal to have the plant go through major fluctuations in climate. Most strains can withstand temperatures as low as 50 degrees fahrenheit without tissue damage. When getting below 40 degrees, you can almost guarantee that the tissue is being damaged. The plants metabolism will begin to slow down making its natural functions to become less active. This correlates directly to the root system preventing the plant from absorbing nutrition, in turn leading to lower production or even death.


How do I determine what size heater I need?

Answer: Give us a call to speak with a specialist at (541) 480-9392.

Can I use a kerosene heater?

Answer: Kerosene heaters will work if you buy the right model. If the model does not burn cleanly it will produce toxic carbon monoxide as well as release a odor. A good rule of thumb is that if you see a red flame it is toxic, if it is all blue you should be in the clear.