TheMadPlanter said: Can you tell me what greenhouse you have? Is it custom?
I have a Riga XL5. Here are the specs:
https://www.exaco.com/rigaXL-g...
They also make a "Regular" Riga series starting with a 7'x8'. The glazing on those is double wall.
No matter what greenhouse you buy, unless you want to go very custom, very insulated - like the CERES greenhouses - you are most likely going to pay a lot for heating if you want to keep the temps at 55 or so even in your zone. 99.9% of greenhouses are NOT made for 4 season growing EVEN though they are marketed as such.
What we are trying to do is squeeze another season out of a building that is not made to grow in during the winter. Would I ever try to grow citrus or summer veggies during the winter? No way, the heating bill would kill me. All I am trying to do is keep my greenhouse at 35+ (which is still task on the coldest nights - last night was 9 degrees) for plants that can tolerate these kinds of temps like spinach, lettuce, cabbage, broccoli, etc.
If you have room in your house and you can move the citrus and palms, it would be cheaper to put them in a room in your house with some
quality grow lights.
