Heating a greenhouse during winter can be tricky! Many people assume that greenhouses will stay warmer on their own. However, once the sun goes down the heat built up in the greenhouse during the day dissipates very quickly, leaving your plants vulnerable to cold damage.
When trying to decide how to heat your greenhouse you first need to figure out how many BTUs you need to heat your space. Wikipedia defines BTUs (or British thermal unit) as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Figuring out the BTUs you need can be complicated however this website makes it super easy: http://www.littlegreenhouse.com/heat-calc.shtml. After you figure out how many BTUs you can select a heater. Greenhouse Mega store has a lot of great options: https://www.greenhousemegastore.com/equip/heating/.
Another thing you can do to help keep your greenhouse warm during the winter is to be sure it is well insulated and sealed. A cheap and easy way to insulate your greenhouse is to add a layer of bubble wrap to the inside walls. The bubble wrap with the larger diameter bubbles works really well for this. Whenever you put up the bubble wrap up you can use clear tape to attach it to your walls. Be sure you put the bubble side against the wall and have the flat side facing out. This creates more space for air in between the walls and the inside of your greenhouse. This space is what creates your insulative layer and protects your greenhouse from the cold air outside. This will also help you with cooling in the summer so there is no need to remove it once you have it up.
Additionally, you can seal and large gaps with expanding spray foam. For small gaps and seams you can use 100% silicone. We have done this on all our greenhouses and it really helps to seal all those little gaps where cold outside air can get in.
(A new pitcher on our collection N. robcantleyi)
If you need any help figuring out how to heat your greenhouse of grow set up you can email us or book a consultation with us and we will help you figure it out! our email is email@example.com and you can book a consultation here: https://www.pearlriverexotics.com/products/consultation-via-skype?_pos=1&_sid=90082984e&_ss=r
As always thank you for tuning in!