It's not clear exactly where you live nor exactly what you mean by "minimum" amount of electricity but the average Z5 should probably think about a pool cover for insulation. Tomatoes might be tricky from both a cost of electricity and a light amount standpoint depending how deep into winter you mean to go. Leaf lettuce, radishes, other cold tolerant crops if you have the room sound best to me and probably done by Christmas.

Last spring (March) it cost $50 dollars a month to run my little ceramic heater and a shop light. I want to eliminate the heater or find a better way to heat or insulate. Oh I live in upstate NY west of Albany zone 5. Do you think I can grow herbs. Does anyone have experience with heat wire?

I'll second the recommendation for the clear solar pool cover.

Have you tried a search yet? There have been quite a few threads on insulating/heating that should contain a lot of helpful information for you.

I'm in USDA Zone 7 in coastal New Jersey, used the following last winter and was very pleased:

1. Above-mentioned solar pool cover;
2. Water-filled containers (tubs, milk jugs, soda bottles) for thermal mass;
3. Weatherstripping on panels and caulk in all gaps in the frame;
4. 1" thick foam board insulation on the north wall and north 1/3 of the east and west walls.

This year I will be adding insulation around the perimeter of the foundation, since I felt drafts there last year.

I did keep the GH at a minimum temp of about 50 degrees, but was very satisfied with lettuce and herbs through winter, a small but very tasty supply of cherry tomatoes from the one plant I overwintered (production was very light December & January, since I did not use supplemental light) and about March or April some snow peas.

I didn't calculate the cost of operating the heater, the electric company really messed up our readings the prior year, so I didn't have a baseline, but our electric bills were not uncomfortably high (certainly lower than our summer bills with the A/C!), so I felt that the benefits of the GH far outweighed the cost.

Don't mean to stray off topic, but the falling leaves usually precipitate a similar fall in my mood, since they bring to mind the cold, dreary months that are so near. This year, however, going into my first autumn with the greenhouse, I noticed I was, instead, excited as I prepared for another season of GH gardening. What a difference!

There are a few folks who've used heated cable - try that search feature. If I happen to find any discussions, I'll post a link for you.

Diane

The winter crops should do fine without much heat. Mine survived high 20s & low 30s with no extra heat. Your temps probably get a lot colder, though. Try brocoli, cauliflower, onion, lettuce, snow peas, & radish. The greenhouse was burried in snow for over a week and the plants were fine.

Thank you for all the input. I hoope people post the progress of their winter GH. I love seeing photos of what is going on in other people's GH.

Over in "Conversations" there's a thread titled "Different Kinds of Benches" in which I posted a photo of my greenhouse in early December, a few weeks after we set it up. Considerably more was added as the season progressed! I'll try to get an update posted. There are various photos sprinkled about on the forums, though, posted by different folks; it's interesting to see the different approaches. If you have the time, do a search for HFGH and browse through the results for photos.

Di