Hi all:

In Zone 7b, interested in growing citrus plants.

CURRENTLY, after my initial greenhouse plans did not work out, I set up a "greenhouse" in the garage. Keep temperature above 60 with electric heater, have multiple grow lights set up. At this point, all is well. And my backup plan is to expand to 10x12 next fall if need be.

WHAT I WOULD LIKE is to set up a 10x12 heated greenhouse in the backyard. HOWEVER, my research so far tells me that it's not realistic without significant heating costs to keep a greenhouse over 55 or 60 degrees.

What do you think? Anyone done so in a comparable grow zone? Any thoughts on a likely heating cost (10x12, zone 7b, 55 degrees)?

If the heating cost is more than $75-100 a month (natural gas or electric), I will probably just continue in the garage. I'd enjoy an outside greenhouse, but it just doesn't seem worth it for costs above that.

Thank you.

Would you be able to attach a greenhouse to your house?
We did that here in NJ, had it built by a professional builder, placed on top of the garage. The greenhouse works as a heat sink during the indoor season, on sunny days the oil burner comes on many times just as the sun goes down. The heat system is connected through the whole house with well placed duct work. Works great and the increase in oil consumption was negligible. I keep night temps at 60 degr F minimum.

Unless you are growing truly exotic citrus trees, you need only keep them above freezing. My daughter and I both keep potted citrus trees. She keeps more than I and also lives in a much colder climate. She keeps her greenhouse at about 40 in winter with a small milkhouse heater and a heatsink (she prefers to call it a koi pond ).

I use a milkhouse heater and, if it gets really cold, a small Buddy Burner but usually, I can keep my twin wall greenhouse warm enough for my citrus and some hardier tropicals with heat lamps. I don't think any of our heaters have ever added $100 to the electric bill.

Unless you are using LEDs, the bill from your lights might be pretty high. I hope you are using a light meter to help you determine if you have enough artificial lighting to keep your citrus trees happy. Unless you have to put on your sunglasses when you go out to the garage, its probably not enough.

Ursula said: Would you be able to attach a greenhouse to your house?
We did that here in NJ, had it built by a professional builder, placed on top of the garage. The greenhouse works as a heat sink during the indoor season, on sunny days the oil burner comes on many times just as the sun goes down. The heat system is connected through the whole house with well placed duct work. Works great and the increase in oil consumption was negligible. I keep night temps at 60 degr F minimum.

Thanks for your thoughts. While that was initially considered, at this point that probably is not going to happen. Perhaps an orangerie in the future! For now I have to consider a free standing structure away from the house. But never say never I am thinking.

Lucy68 said: Unless you are growing truly exotic citrus trees, you need only keep them above freezing. My daughter and I both keep potted citrus trees. She keeps more than I and also lives in a much colder climate. She keeps her greenhouse at about 40 in winter with a small milkhouse heater and a heatsink (she prefers to call it a koi pond ).

I use a milkhouse heater and, if it gets really cold, a small Buddy Burner but usually, I can keep my twin wall greenhouse warm enough for my citrus and some hardier tropicals with heat lamps. I don't think any of our heaters have ever added $100 to the electric bill.

Unless you are using LEDs, the bill from your lights might be pretty high. I hope you are using a light meter to help you determine if you have enough artificial lighting to keep your citrus trees happy. Unless you have to put on your sunglasses when you go out to the garage, its probably not enough.

So far just Meyer lemons (but an accident ending up killing the plants I had), key limes (which seem to be doing well even though I thought they were less hardy than the lemons), and fingerlimes.

Can you tell me how big those greenhouses are?

Using LEDS. The lights aren't quite that bright, but I was surprised at how much new growth I see, especially on the fingerlime.

I think Daughter's greenhouse is about 12 x 8. Mandarins, finger limes, yuzu, keylime, kumquat... those are the ones I can think of. She keeps them in the greenhouse year round. I move things in and out but only have a couple of citrus left (gave the rest to Daughter). I think she is in zone 6-7 but the koi pond and one solid house wall (her's is a lean-to) keep it warm enough with just a milkhouse heater and a big fan to move the air. She also has cymbidiums and a few other terrestrial orchids.

Mine is free standing (12 x 16), my low temps are in the mid-20 but my 6 or 7 heat lamps keep things warm enough most of the time. If I'm concerned, I break out the milkhouse heater or the Buddy Burner. I'm wintering over citrus, cymbidiums, jade plants, birds nest ferns...

My zone changed recently to 7b [i'm on Long Island]. I have a 200sq/ft shed with 15x7 old Everlite greenhouse. It's my first season so it's still a work in progress. Like Ursula said the shed acts like a temp buffer for the GH. I keep tropical plants and tropical fish in a pond. In Nov i had a Diakin 24k mini split heater/AC unit installed. I have it set for 64 degrees and it seems to keep the shed at that with the GH a few degrees cooler. My first elect bill was about $60 more than usual. I'm not sure if that's an entire month. I also run a small wood burning stove to offset costs. The GH is very leek [air and water] due to a poor install, but my main issue is single pain glass has an R value less than 1. If costs get too high i'll try to figure out a way to better insulate. During the day it's fine [in the winter], it was about 40 deg outside and 80 in the GH. Then i'll have the opposite problem in the summer.