I purchased a Palma heater, used though December, when the temps started getting really cold, I stopped. The biggest issue I had was Northeast Ohio does not have enough sunny days. I was growing veggies. But I did have cucumbers in November. The lettuce I moved indoors, under a grow light. But that was with my greenhouse set up, and my experience. The cabbage etc did not form heads. I didn't want to spend more on grow lights outdoors. But that could always be an option depending on where your greenhouse is located in your yard. The prices have significantly increased. one I bought new the other I purchased was refurbished.