Heating Your Greenhouse

A customer asked: I’m wondering if you could advise on a size (BTU) heater I would need for my size greenhouse in my climate?

Our Response:

Sorry – the answer is not that simple. For one thing I do not know your climate. You will have to tell me. And next: how warm do you want to keep it in side: over wintering outdoor plants requires less heat than, orchids or growing form seeds during the winter.

Secondly, it greatly depends on what you are doing with your greenhouse – for example the more plants the fuller it is the more natural heat is retained and generated. There is a big different between half full and full: can make 10-15º difference. Large raised beds are a great heat generator.

Another option is: to use 1 or 2 large open troughs – 70 gal. + (full with water) (from say Tractor Supply) – these to can add 10-15º at night. And at the same time they offer additional humidity during the cold winter months.

One of our major customers offers the following calculator: https://greenhouseemporium.com/greenhouse-heater-calculator/

Generally you will need to experiment.