Can vegetable greenhouses be heated with charcoal?

Yes, but considering safety, we need to pay attention to the following matters:

First, it is best to use a heating stove to burn charcoal, not directly in the fire, so as to avoid insufficient combustion to produce carbon monoxide and lead to poisoning.

Second, the heating stove and flue must be unblocked to avoid back smoke.

Third, flammable materials such as plastics should not be opened in the flue to avoid fire.