As stated above, I would work on insulating the shed as a first priority.

You don't want your heat signature excaping, snow melting off the roof, etc... and doing this will also increase the temperature inside. Most people don't choose to grow in a shed, because Leo doesn't have to worry as much about entering it since it's not technically your home. Whatever happens, best of luck.
Comatose Reviewed by Comatose on . Help: Heating a very small grow I am doing a super small grow in an outdoor shed for my own medicinal use. I just started flowering and it's getting pretty darn cold out there already. How can I heat this tiny space without having to heat my whole shed? The grow is only 1.5 by 2 feet but I have about 6 feet vertical clearance. I have thought about : - Super small propane heater... but how would that work? and what about humidity? - Heating blanket or 'propagation mat'... but will 40 watts of heating power make any Rating: 5