I live in central NY, they say its zone 5, but its really 4. I have a glass 8 by 12 foot gh. I don't use it in the winter as it is free standing and would cost too much to heat. I do use it to grow up my seedlings. I put them in around April 8th, and have to heat it at night for about 2 weeks, until it warms up enough. I then put those plants outside, and put my orchids in it. When I heat it those first few weeks in April, I go through a 20 lb. propane tank every 3 days or so. After that, it mostly stays just on the pilot light and that seems to be enough for another few days. At that point, I turn it off during the day. I also have two, 50 gal. water barrels for solar heat and another couple of 30 gal. containers. It has a cement paver floor that helps hold some heat. My goal is to move it and attach it to the house. Then I would just get a 100 gal. propane tank for heat and keep my orchids in it all the time. I would have to raise it up 3 feet to match a door to the house, so I would gain even more room. Sterling

The VERY approximate rule of thumb is one zone per layer of protection, but this is pretty variable as you said. Besides, zones are not that important unless you have perennials or plan to grow vegetables through the winter. Even in this case, it's complicated by the issue that a hoophouse won't have protective snow cover inside, therefore cancelling out zone benefits in mid-winter. If you want to maximize your warmth at night as well as winter protection, use heavy row cover (winter) or light row cover (spring/fall) for the low tunnels, instead of regular plastic. Optionally, plastic can go on over the row cover (only in winter, otherwise you can cook the plants). In a hoop house, water drums are fairly insignificant. Much better to rely on the ground as a heat sink and insulate the ground + plant system from outside. I have a single layer PC GH (behaves like a hoophouse) with low tunnels made up of double layer light row cover and 4 mil poly. Kale, radishes and turnips planted in there. Lowest temp. outside this winter was 15 below zero F. Lowest inside was +19 F. Daytime temps. are 10 to 40 degrees F above outside, depending on how sunny it is and how strong the sun is. Beware of bugs (aphids, scale, mealybugs) that thrive in the warm damp environment in a hoophouse in fall/early winter.

OkiePokie, Sorry. I never came back to this thread in 2011 and answered your question. My hoophouse is 12' x 24' and even with 50% shadecloth (Aluminet) on it and with all 4 vents and both doors open, it is too hot to use in summer. Without a fan running, it hit 140 degrees this summer, and with a fan it still was incredibly hot. I mostly use it in the cool season. Of course, inside a hoophouse during the day, it is going to be hot because of the greenhouse effect, so I have to run a fan...and that is with shadecloth on the hoophouse. In Feb.-April of this year, even on cloudy, overcast days and with shadecloth, open vents, open doors and a fan running, the greenhouse was over 100 degrees. It is too bad it doesn't hold that heat at night. The issue with hoophouses made with a single layer of greenhouse plastic is that they are just as cold at night in winter as the outdoor air unless you're running a heater in there. A hoophouse with two layers of plastic sealed together with an inflator that blows air in between the two layers of plastic might stay a little warmer, but mine only has a single layer, so I am just guessing at that. I think even with an air-inflated double layer of plastic, you'd have to run a heater on cold nights or even on cold days. Plastic alone just doesn't hold in the heat, and I never expected it to. Before we built the hoophouse, we already had a glassed-in, unheated sunporch that is toasty on winter days but cold at night. I mostly use the hoophouse to raise seedlings for transplant into the winter/spring garden. I start them inside on a light shelf, and move them out whenever the weather permits. The hoophouse is an intermediate step between them growing indoors in a very controlled, heated, environment and going outside into the elements. Before we built the hoophouse, I would have to carry the plants outside to harden them off in ever-increasing increments of time, and then carry them back into the house, garage, potting shed or sunporch to get them out of strong wind or to protect them on a cold night. This past spring, which was admittedly warm very early, I moved the plants out to the greenhouse in late January or early February and never had to carry them back inside, except for pepper plants, which stayed inside until March. On a few chilly nights, I draped Agribon over them inside the greenhouse to give them a little cold protection, but they did just fine in the unheated greenhouse at night even when the temperatures dipped down into the low 30s and upper 20s. The Agribon is what kept them from suffering freeze damage. I've used it in the garden for years on cold nights, and it is wonderful. A large hoop house that is not heated will not stay any warmer than low tunnels, and I know that because I've used low tunnels for years. Hoophouses don't have insulation, although you can purchase and add bubble wrap type insulation. Busy One has some on his greenhouse and you might be able to do a search here and see what his looks like inside when he has the insulation in for the winter. I know he posted photos to show me when my greenhouse was still in the dreaming/planning/building stage. I haven't tried using large containers of water, for example, as solar collectors to see if they'd help the hoophouse stay warmer. I might try that if it ever cools down enough this fall for me to grow some winter crops in the hoophouse. We were in the 100s last week, and are in the upper 90s still and the greenhouse is still in the 110-120 degree range every day. My hoophouse hasn't been exposed to a lot of strong wind yet, but withstood 62 mph winds during a severe thunderstorm with no issues whatsoever. It also has withstood straightline winds in the 50-55 mph range that brought down some trees in our neighborhood. Carol, I have some of my hoops up, but haven't put the covers over them yet. I do have a row cover floating over the snap peas, but I'm letting it float without hoops. I probably will put up row covers over some of the hoops next week if the grasshopper population doesn't start dropping off like it normally does at this time of year. So far the hoppers are only eating purple sprouting broccoli and sugar snap peas. They have put a few holes in the leaves of southern peas and bush snap beans, but not enough to hurt their productivity. Normally we are seeing fewer hoppers at this time of year, but in this oddest of years, we are instead seeing more and more as new ones keep hatching. My cool-season crops probably would be happier if I'd drag out the shade cloth and put it over them. They are hanging in there pretty well, considering the high heat, ultra-low humidity (we bottomed out at 12% a couple of days ago, but only went down to 18% today) and gusty winds. I'm surprised how well they are tolerating the heat, all things considered, and I would have put shade cloth over them from the beginning if I had realized that September's daytime temperatures were going to continue running 10-15 degrees above average. Late today some of the lettuce and kale looked a little wilty and I had to promise to water it in the morning so it wouldn't sulk. As soon as it cools down some more, I'll move the container plantings to the greenhouse, but at the rate we're going, that's not going to happen for a while yet. Elected4life, I see that you are new here. Maybe you need to go back to the "instructions" and note that no advertising is allowed in any of the forums. I do not mean that in an unkind way, but this is iVillage's forum and that's their rule. Dawn

The most recently posted Long Island street view is from 2012! No proof they are still there after the 2 polar vortex winters. And the other recent winter that was very cold in New England but not as much down here. (2016 IIRC: well below 0F on Martha's Vineyard. Have no idea how LI fared) They often look out of place in typical residential settings but I think those twin Seattle trees suit the house and are well taken care of so I give them a pass! Good catch GG. I am actually wondering if the NW DC, Bethesda, and Baltimore trees survived this horrid summer...by far the most humid I can remember. We barely had any comfortable dewpoints throughout September, not until the last few days. USUALLY cold fronts start pushing in some crisp weather by the 2nd week of Sept. It was a constant steambath since May. And yes it is humid compared to the PNW, but constant dewpoints 70F or above are not normal at least up here. There's a reason you see at least a few old ironclad rhodies in the DC/Baltimore area, but none in the deep south. And other than the late June/early July drought/heatwave - just long enough to be a nuisance - incredible rainy spells, one after another. I'm lucky to have only lost a couple important rhodies to root rot. OTOH it was nice to not worry about watering the 6 or so new planted camellias in my garden. They are so thirsty in the first year!