Hi from central Indiana. I'll be building a greenhouse and a solar dehydrator the remainder of this winter. My instincts tell me the greenhouse should be glazing: some east, south and some west, with north an insulated wall. Yet I don't see this in many designs. Does indirect sunlight from the north really help, compared to the insulating effects of a wall. And any ideas about combining a greenhouse with a summer dehydrating station. Fran

@fran365 ! I don't have answers for you because I built our greenhouse from a kit. The directions and a few good builders on NGA told me what to do. Even though there were some options during the build, there wasn't as many as when you design your own. But I can tell you the direction your gh faces is important for optimum sunlight during all seasons. I debated whether to angle my gh on the square platform to get the most sun. In the end, I concluded the gh sitting askew would bug me more than having "just" 85% of the sunlight. Happy with my decision. IDK how dehydrating would work as it remains almost always humid in my gh year 'round here in Houston.

Indiana, eh? Snow supports may be a consideration for you. Other than that, I will let the experts chime in here to give you some insight. Especially the snow part. That is foreign to us here in the South!

Welcome to NGA, Fran!

I agree about the humidity in the GH, at least from my experience -- so I'm not sure how the dehydrator would work. There would certainly be plenty of heat when the sun is shining.

One thing I've discovered about GH placement: My original GH was an 8x16 Rion, which I oriented in an east-west direction after doing some research. Despite having 6 roof vents and one double door, that GH would get extremely hot during the day. More recently I have also set up a 7x15 hoop house, which is oriented north-south (after seeing this recommendation somewhere, which would supposedly prevent "hot spots" inside as the sun passed from east to west; truthfully, I almost had to orient it that way because it's inside my garden and that was the way it fit the best).



This hoop house has no vents other than a door on each end, and yet the temperature inside stays much more moderate. Hot, of course, but not to where it cooks the plants. I've had such good luck growing tomato plants in there that we decided to put up a 16x20 hoop house that would both accommodate benches for seedling flats and an area for in-ground growing, and I've also oriented that one north-south, with a door at each end. The north wall is covered with plywood, the rest will be covered with 6-mil greenhouse film.

So, no, I don't think the light from the north wall is significant. Are you planning to use your GH year-round? If so, you will want to have glazing that is as efficient as possible in terms of holding in heat, and yet will also need to allow for venting -- because on a sunny winter day a GH can get surprisingly hot.

I'm looking forward to hearing more about your plans!

Incidentally, your photo in the original post didn't show up; to add a photo just click on the "upload an image" button underneath the box that you are typing in and select the photo you want from your computer.

Nice to hear from you , Weedwacker and Shady green thumb. Last season was the best growing I have seen in > 40 years, most plants grew and produced wildly A greenhouse would only help and I'll keep this forum updated as things happen. I'm thinking the solar drier would have to be separated from the atmosphere in the greenhouse, but could reside in the same structure. I'll have to stew on that one. Fran

Southern climate here too but my greenhouse has a concrete floor. As a result, I don't deal with as much humidity in summer. It does stay entirely too hot in summer to leave plants in even with shade cloth. Are your plans to grow in your greenhouse year around? Will you be using it primarily for vegetables?

I do think in your climate I would use the north wall as an insulated wall or perhaps even a heat sink in order to help provide heat in winter.

I should think you would be able to use it as a dehydrator also although the sun isn't as important as the heat. Exposure to sunshine when drying some produce fades or discolors it. Dehydrating in the greenhouse would prevent dew, bugs, dust from affecting your drying produce. I use mine in summer for curing harvested onions, garlic, potatoes and herbs. All do better out of the sun while drying.

Mine is 10' x 20' and I have two retractable clothes lines that I do use in the greenhouse in summer. Fourty feet of clothes line and if I drop something, it hits concrete. The birds can't fertilize my clean laundry, the shadecloth prevents the clothing from fading and I still get the smell of freshly dried sheets.

Like everyone else, I'll be interested in following your path to completing the greenhouse.

@pod A clothesline in a Southern summer greenhouse! That's GENIUS!!

Even in NW IN, my little greenhouse gets too hot for plants in the summer. I have shade cloth, two roof vents, a wall vent and a door and generally keep a fan blowing 24/7. The clothesline idea is excellent! Mine is a metal-framed, poly-paned lean-to model attached to the south side of my garage on a roughly east/west axis. Have gravel floor with cement pavers. It does need supplemental heat in the winter, along with rigid insulation around the bottom of the structure and supplemental light for our cloudy, gray winters. When the sun does come out to heat up the greenhouse, I open the pass-through door to the garage and let the excess warmth into the heated garage (hoping to be energy efficient).

Cindy, you mentioned "rigid insulation around the bottom of the structure " which is very important in GH construction. How is yours insulated? DH built mine and used landscape timbers (like log cabin walls) about 2 1/2 feet high. It really makes a difference in how warm it stays. I later read that most of the cold enters a greenhouse at ground level. I've also read that anything, even straw bales around the perimeter will help insulate from the cold seeping in.
I love the idea of heating your garage. I always thought if I had to move back to the frozen tundra of MN, I'd want a greenhouse of the south side of the house. That would help make winter more tolerable.

Straw bales! Good idea! I used the rubber flooring that go togeter like a puzzle over te decking floor in the GH. The deck was nice to keep it cool in the summer but the ground exposure kept it too cold in the winter. I was going to pull up the pieces but it wasn't made for that. It breaks. Or I bought a cheaper version from Harbor Freight?

If it is like the stuff I've seen, probably gets brittle when cold?

Maybe so, Kristi? But the floor over all remains pliable and soft.

Very clever. I'd have not thought to use that. Isn't it made like puzzle pieces that snap together?

Pod - didn't have the foresight to construct a solid wall ( like your timbers) around the bottom. And it would not have fit under the eave of the side of the garage. I bought rigid styrofoam panels and stack them around the inside perimeter about 4 ft high and then cover with a layer of foil bubble wrap. I close up the door to the outside for the winter and use more insulation to keep out drafts. The low window vent on the opposite side of the GH is also closed up and insulated. I have a sand/gravel floor with pavers down the middle for walking. I have a natural gas wall-mounted heater and run a fan 24//7 to circulate warm air. A few years ago, DH installed a door between the heated garage (a separate ceiling mounted natural gas heater) and the GH so I can get into the GH without walking outside in snow or rain. I do remove the insulation once the weather warms up in the spring. On sunny winter days, the GH can reach 80F and I keep the door open to the garage to help heat the air in the garage and reduce heating bills. We don't have a basement so our garage is our main working space in the winter.

I think it works wonderfully for you Cindy! How delightful to have a workspace near the greenhouse. I didn't have the foresight to 'fix' the walls like that. DH built it and after the fact I found out how good it worked. The last two winters have been mild and I've not even lit a fire in the greenhouse. No complaints of course.

pod said:Very clever. I'd have not thought to use that. Isn't it made like puzzle pieces that snap together?

@Pod yes, square puzzle pieces made of 1/2" (?) rubber. Popular in colors for kids' room and now other purposes. Usually sold in packages of 4.

Pod - I think, after reading about GH construction over the years, I might have gone with sinking a GH down into the ground a few feet for better insulation. Of course, I would still have a small one due to available space on the side of my lot. I get nice heat gain on sunny days but winter nights can be brutal.