Last winter I followed advice in Elliot Coleman's book (Winter harvest handbook) and had great luck in *harvesting* fresh vegetables all winter. They did most of their growing however in the fall (I started them all in late September or later) and then later in the very early spring as in the winter months they barely grew (although they did a tiny bit). My set up: Hoop house - It was an existing (built by me and my husband a handful of years ago for season extention) 12x16 plastic covered hoop house. We made it out of plastic conduit and the only thing we modified for the winter is that we swapped out the flat 4 way fittings at the roof peak with adjustable angle fittings. I found that 45 or 90 degree fittings didn't work (too sharp an angle) and I didn't want to not have an angle for the snow load so I went with manually setting the angle as steep as I could with the adjustable ones. (You can find them by googling "PVC 1" Adjustable Ell Fitting 3 Way" or "4 way"). We never removed snow off the top of it - By design or by luck the snow would shed off the side. (Although I hear brooming it off is good practice.) I sealed the window and door with weatherstripping. I also added ~ 800 gals of water - some large tanks (which were a royal pain to get in) and lots of single gallon containers. against the north wall. I also added 1" foam insulation along the north wall - including covering 1/2 the "ceiling" on the north side (taped to the conduit frame in some areas). I dug the foam insulation ~ 6" deep around the perimeter. I then planted in two 18" rows separated by a small 1ft step path - all under a 4ft wide floating row cover (the row cover hovered on smaller plastic conduit hoops). Under the row cover in the small 1ft step path I put as many gallon jugs as fit leaving me with step spaces. I also put a few 1L and 2L bottles on the outside edges under the row cover. I also put one strand of old-fashioned (ie not LED) christmas lights suspended from the conduit as my "emergency" heat source. I put my thermostat for my lights outside my row cover and set it to turn on at 28*. I also grew a few earthboxes full of veggies but I found that anything in a box didn't grow nearly as well as things in the ground. I think the roots get too cold and they stop growing much, much earlier (but they didn't die - just didn't grow as much) even though they were under the same row cover but they didn't die. The last thing I did was put a small muffin fan attached to a tiny solar panel under the row cover for air circulation. I had my window/door always closed (ie I disconnected my autovents) for the winter months (Dec-Mar). I also never went in to harvest except during the day (almost always a sunny day) when opening my row covers wouldn't release any trapped heat that was vital for the night. I weighed down one side of the row cover with cylindrical bags of sand that I could easily remove and then the other side with soil/rocks piled on top. Watering was mostly a non-issue, but I'd carry in my water in jugs on sunny days and water by hand. I think I had to do this maybe 3-5 times all winter (ie monthly). With this set up I successfully grew: kale, leaf lettuce, carrots, beats, chard, mache VIT, bok choi, spinach, etc. For most plants I would harvest outter leaves and leave the inner leaves to continue growing. With that set-up each plant continued to provide until the late spring heat caused them to bolt (which was fine since I needed the space for the next round of crops). The temperature inside the row cover was much more stable than in the hoop house in general. The temp in the row cover never dropped under I think 25 - even after multiple cloudy/stormy days. In addition my hoop house is drafty so perhaps with a more sealed-tight environment no extra energy would be needed and/or maybe more ventilation. Oh and my hoop house is on the north side of my property and has mature trees ~ 50 feet away from it on the east side which did shade some in the morning (but not so bad because they didn't have leaves) and then we have evergreen trees that would shade the late day sun as well. I still think it's worthwhile but it depends on how much sun you get. I'm planning on building a "real" greenhouse (twinwall, etc) and am spending this winter scouting for the right location (best sun). I plan to use an earthen floor due to my experience of growing in pots vs in the ground, but am still doing my research for that as well. I've read that wherever possible you want to insulate in the ground to keep from losing heat that way. I plan to do that with my final greenhouse. Also wherever you are realize that both snow and a kneewall (if you have one) will shade part of your greenhouse floor in the winter due to the low sun angle so you may lose "significant" growing space that way.

I am new to this, as my GH was just completed in late August. but the air is continually circulated into the house with a small window fan. Many folks use humidifiers because of dry winter air due to fireplaces, so this also is my humidifier. My thermastat in the house is set at 66 this year, much cooler than usual, but will still add heat to the GH on cold nights. On sunny days, the GH heats the house for the afternoon at least. The company that I bought the rain barrels from said they would not likely freeze solid and there would be free water available. I have a cutoff at the barrel so the hose would not freeze and burst between the barrel and the GH. So far, I have not turned the water off. The hose did freeze at least once, but did not get damaged. As the day warmed up, water began to be available through the hose again. Any damage to the hose or Rainbarrel would be so easy and inexpensive to repair, I am not worried about it. The running water from the barrel is so convenient, I hope to use it pretty much all winter and would definately not put it away

A good reference book about building greenhouses in our climate is Gardening Under Cover: A Northwest Guide to Solar Greenhouses, Cold Frames, and Cloches by William Head. It discusses siting, styles, and heat sinks. Also shading during summer if you want to use it year round. You need clear for winter use as we have such low lighting to keep things growing. The KCLS has it if you're in King County. I scanned the greenhouse structure page, so email me if you'd like me to share it. It talks about pitch of roof, type of roof & functions. Best wishes & post a photo for us to see. Corrine

Hi, If you have a slope, I would go with raised beds, and infill with gravel. I would think that when it rains, the rain is going to flow toward your structure. If you have gravel laid down inside your greenhouse, the water will flow on through instead of being a problem. Also, if you place your raised beds under your trusses, you can run chicken wire up to the ceiling and have tomatoes or green beans or what-have-you. Will this pitch allow for snow load and shedding of same? This new houzz website, I can't tell where anybody is. I'm new here, liked the old site much better. You'll need a 36 inch door to accommodate your wheelbarrow and other implements. The wall closest to the solid frame could be made into your tool storage/work area. This is a picture of my 30x50 greenhouse, what you see outside the door in the distance is about 4 feet of snow. I am showing the truss design so you will have an idea of how to make it sturdy. It is designed to carry heavy snow loads and withstand 150 mph winds, like near a tornado or other crazy weather that we have nowadays. This is an "after" picture, looking East toward the same door. I put in raised beds and have started filling the paths with gravel. On the left side are tomato plants growing toward the ceiling. I ran a 2x4 across the bed every 4 feet under the trusses so I could attach the chicken wire. The 2x4 also helps to keep the bed from falling outward from the weight of the soil. On the right is my greens bed. It has row cover on it in this picture, but under the row cover is a 2x4 square with wire fencing running across it to grow miniature peas on.