How cold does it get? Your greenhouse, that is.

I am wondering if I can keep a greenhouse above 40F all winter. Or is that too much to ask?

AnalogDog, I keep my GH heater to come on when it's under 40%f, and it was quite inexpensive. it depends how big your GH is and how insulated the glass, plastic, is.. mine is double. Jim

Good to know, Jim. I think I've had that same question in the back of my mind. What kind of greenhouse do you have?

Thanks Jim, I am looking at the GH sites right now.

AD, I try to keep mine at 50 or so. I have an inexpensive heater in each of the three that I have. I have no idea how to figure out how much it costs over the winter, as I also have flourescent lights in them. The first of my greenhouses is part of a barn structure so I am pretty sure that is the one that takes the most heat in spite of the fact that it is insulated with building insulation. The second greenhouse I got is aluminum framed and came with its own heater and thermostat. It is made of ribbed plastic, double wall, and I think the third one, a Rion (?) is by far the most heat efficient. It is also plastic, double walled.
I find that I have to be really careful to not overwater as mold can easily appear at that temperature. In addition, last winter with the long cold spell still had me lose a few of the more tender things that were closest to the walls.

katie59, I have a very small greenhouse that I bought when I was just starting to garden 6 X 8'. now I could use and 8 X 12 easily. it does keep me more organized. I do have a small one that I got from Charleys. it helps. I'm thinking seriously about buying one of the carport kits 10 X 20 at Costco and buying enough shade cloth to cover, I only need it April-Oct so the hostas don't get burned up. the hostas need a cold period so I wouldn't be heating it. I lost a few hosta in the 6 X 8 because I had the heater coming on below 40%. this year I have some of my tender perenials at a friends house. but I haven't decided what to do with my Brugmansia, I'm thinking of putting them in my basement, I don't know if I do what I do with my Musa bajoo, Musa sikkamensis, would work. I dig them up cut all the leaves off then I store them upright in wood chips. they come out just fine in May when I plant them out again. Jim

Jim - I have a carport frame for free if you want it. It has a couple of dents, but it goes up nicely - all you'd need to do is get a tarp.

I keep one of mine at 50 and one at 60 (the one that I start my seedlings in). I also run big halied (sp?) lights. Don't know the cost, but know the worth when I putter around them in the deep dark winter....

katie59, that very generous, I'll contact you on dmail, thanks, Jim

I have a glass greenhouse and after several years of insulating with bubble wrap last year I sprung for double wall polycarbonate sheets, had most of them cut to fit, which is very cheap to do, and now the greenhouse stays very nice and toasty without a lot of fuss. I have several heatmats on shelves and they give off a gentle radiant heat that keeps the greenhouse close to 50 degrees without extra heat until the really cold part of winter. Then I have a portable electric heater that I keep on low. It has a thermostat so I can regulate the temp. It also has a fan that keeps air circulating, which is very important in the winter.
I bought the polycarb panels at a plastics supply house in Tacoma and they were Really cheap compared to Charlie's greenhouse, or any other supply with the word 'greenhouse' in the name. My greenhouse is 8 x 12 and I was able to completely retrofit it for less than 300$. It sounds like a lot of money until you see my utility bills from the winters before. Shudder.

If anyone is thinking of buying a greenhouse, especially from the highpriced place up north of here that starts with a C (which I referred to earlier in the post) might I recommend checking out BC Greenhouses first. I ordered mine from them directly. They manufacture the same greenhouses that are sold retail at the expensive places here. I saved several thousand dollars, yes THOUSAND, by ordering directly from them. The greenhouse kit arrived on a truck and my dh and I put it up in 2 days. Their customer service is excellent.

http://www.bcgreenhouses.com/

I have a SunGlo greenhouse that I bought nine years ago and absolutely love. http://www.sunglogreenhouses.com/

Thanks for the advice Pixy. I have been on BC's website drooling over the selection. I would need someone to put it together, though. DH? Bad idea...not going there.
Of course I would prefer the "Plug and Play" 16 x 20 version. not a reality today.

I would like to have the one from seattlesheds.com called theSun house. I need a smaller one so I'm going to see if our handiman can build it for me this winter. I'm so excited.

Kate - you know I'd be happy to help. It'd be prep for when I get mine . . .

Lots of good information about greenhouses here.

Not a lot of man strength needed to put these together, actually. You could totally leave your dh out of it.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeee!