I agree with calliope. 60 degrees is way too warm. In fact,you would be able to grow tomatoes with night temps. of 60 degrees if you set out transplants now. For the onions and brassicas, I would keep it at 70 during the day and 40-45 degrees at night. You can also try spinach and early-maturing carrots.

So then 50ish at night would be the goal?

Think of those crops you'd normally put in a vegetable garden considered 'cool weather' crops. Where it says can take light frost, or put out after danger of frost. We don't get consistent night temps of sixty until may or later. And our nights then are anything above freezing. Anything you'd plant out by then in your garden is going to do fine with cool and I mean COOL night temps. You'll get sufficient day temps with just the solar gain on sunny days and a little help from your heaters on dark ones. You'll also want to consider that there won't be any pollinators in your g'houses over winter. Leafy crops are cool, because who cares? LOL.

Your seeds will be germinated before winter sets in and even at 55, with domes you'll have sufficient heat to germinate most everything.

If I am actively growing tender seedlings, I set my stat at 55. If I am not, I may even set it lower. If I am just running cold crops and holding over annuals for the next season forty five is fine. At those temps I find things like lantana get purplish from the temps, but survive and quickly snap back when temps are raised.

I am planning on growing veggies and greens in the winter as well. Never tried it before other than over-wintering plants. My gh is in the sun most of the day till around 2 or 3, so i have supplemental lighting plus Dayton electric heater to come on when the temp drops to around 40*F in the gh. Usually rises to around 50-53 then the temp slowly drops again until the t-stat turns it back on.

We wont be growing any food crops in our GH this winter since insect pests and fungus diseases attacked them every time. Whitefly and spider mite being the worst. Then came the ants and aphids. The GH will harbor orchids and some tropicals I've kept. Trying to better vent the GH in winter just drove the electric bill up. Organic insecticides were of no help with the insect pests.

Gh2, I had all those same issues this past year and the problem is not temps, or humidity, it's ventilation. You have to keep the air moving in there to keep the pests and diseases at bay. Ants are a sign of aphids, the aphids prodice a sugary waste product called honeydew and the ants eat it. They cohabitate with the aphids for this reason. Get rid of the aphids and the ants will go away.

I tried everything under the organic sun to get rid of whitefly and spider mites and nothing worked. Then, I fell off the organic wagon and fought the little b&^$!*s on their own terms and won. It's an ongoing battle though, so my success is only temporary.

I also placed screening over the vent ducts to keep out the flying bugs like cicadas, grasshoppers, moths, mosquitos and such. I installed a door sweep at the threshold and rubber insulation around the edges of the door to keep out everything else that wanted to come in for dinner. Cheryl

I can't afford to heat the Rion if I keep vents open 24/7. The heaters never shut off. Been there - done that. The bill was almost double. Saw little difference in the plants/pests. The vents open automatically on sunny winter days when the heat doesn't come on. I had 6 fans running in the GH to keep the air moving. The way the vents are made on the Rion, it's not possible to screen them. Grasshoppers and cicadas have not been a problem. Since the only insecticide that works (but not on whitefly) is a systemic, I wont try and grow food in my GH anymore.

Wonder what you used for the spider mites?

They have been a constant pest for me to

Then, I fell off the organic wagon and fought the little b&^$!*s on their own terms and won. It's an ongoing battle though, so my success is only temporary.

I have an unheated high tunnel greenhouse. I am in zone 5 in PA. Last winter I harvested a variety of lettuce, parsley, beet greens, mizuna, tatsoi, radishes, arugula, and spinach in the coldest part of winter. The trick is to have the plants at picking size before their growth stop. Read the Four Season Harvest by Elliot Coleman. I could have had beets and carrots if I had gotten them planted in time plus a lot more but I got started late. By the time February comes around you can be replanting all of your cool weather crops - I plant directly into the soil floor. I used no heat at all and put a row of smaller hoops over the rows of crops and covered this with row cover. This gives you an inner second layer of protection. Understand that my high tunnel just has plastic covering so it got very cold at times. I harvested all winter even on the coldest days. You wait until the temperature in the greenhouse reaches above freezing in the middle of the day to harvest otherwise the plants look pretty wilted but they are alive. It was so great to have garden fresh salads in the dead of winter!

Grper, sure it will be warm enough to raise tomatoes and cukes, even if you lower your temp to 50! After all, it gets hotter than that on sunny days: we open the windows into the laundry room to get the use of the heat when it gets around 80 in the greenhouse, and it often does. We grow tomatoes and cukes. Also, I grow a lot of lettuce mesclun and such but it's true bugs are a problem -- this year I am buying greenhouse foggers, "total release" cans from HPS or whomever to try if I can keep them down. At some point when they get bigger one has to just give them up and put them outside to transplant or throw on the compost.

There are some very small early sweet bell peppers I want to try this winter. Mostly I winter over coleus and all the other ornamentals and start stuff early for spring planting. I think I'll be starting cole plants and such as early as Jan 1 this year. They always seem to be late, and there's no need for that with a greenhouse.

HeirloomTomato:

I have 3500 square feet of high tunnel space that I am growing Haikuri turnips, beets, lettuce, spinach, radish, bok choy, tatosi, arugula, carrots, beets, green onions, napa cabbage, broccoli, bell peppers, and green beans in. The last two are carry overs from summer, but they are cranking stuff out, so I am not quick to pull. Also the beans are in the movable buildings and I can move the building and protect the outside crop.

I have a small winter CSA and working on planning a winter farmers market.

I am also going to be using low tunnels this year over the 450 broccoli and cauliflower plants I have outside. I haven't put them up yet, but I am getting ready to soon!

Jay