We bought an old farm house and property. On the property is an old quonset hut dug in about 4'-5' deep. It was used previously as a spud cellar but for years has collected junk.
I'd like to convert it to a greenhouse. It's 80' long x 30' wide and about 12' high.
Not real sure how you would convert it. Most quonset huts I've seen don't have a frame as such.....the metal IS the frame and the roofing/siding at the same time. Looks like you'd basically have to start over with a frame of some kind and cover that with something that lets light in (plastic, polycarbonate panels, etc)
I would like to grow tomatoes and peppers in the winter but east Idaho winters get very cold.
I don't want to spend a fortune heating the thing. What alternatives or options do I have to traditional heating systems that will keep the greenhouse warm enough during the cold winter to grow tomatoes and peppers?
Another thing to note...it's not JUST the heat. I have a small greenhouse, very well insulated (built into the mountain on the north side, south side is triple wall polycarbonate panels for glazing), and we have tried to raise tomatoes here (Tennessee) in the dead of winter. What we find is that DAY LIGHT is as big an issue to production as heat. I could keep the heat up (maybe fall to 50 at night, with daytimes well into the 80's), but the lack of hours of sunshine is something you can't get around unless you plan to also artificially light it. The plants simply "know" it's winter, and while they will grow, they just don't produce a lot.
What we have since concluded is it is better to have LATE tomatoes by going into late fall with plants nearly mature and bearing, then start plants again about February for EARLY producing.....say 2 months ahead of outside garden raised. Haven't tried peppers, so I don't know on them, but suspect you'll find similar results.
On heating:
Insulating and design is going to be a huge factor. As I said, we have a small (12x20) greenhouse I built back into the mountain. The north side (20') and east side are almost completely underground. The south side has a 30" raised bed on the outside as an earth berm. I used triple wall rigid polycarbonate panels for the south facing cover. Typically, it will stay above freezing (barely) on a 10 degree night with no auxiliary heat.
We also built a 20x36 hoop house last fall. 30" tall raised beds around 3 walls, single layer of greenhouse plastic sides/top. It will only stay about 5 degrees above outside temps. This year, I poured the center floor with concrete and built a 5'x20' raised bed down the center. Put 3/4" pex floor heating tubing in the concrete, the center bed, and part way around the outside beds. I currently installing a solar water heating system that will run hot water in that pex tubing, and hopefully keep the inside above freezing this winter. We use it to mostly raise cool weather stuff ( broccoli, cabbage, carrots, lettuce, etc), so it doesn't need a lot of heat....just to stay above freezing. I may also add a second layer of plastic to the top with an air inflation fan.....waiting to see how the hot water system does as of right now.
You could do something similar. IF I were building it from the get-go with hot water heat in mind, I'd dig down about 2-4' (depending on whether I planned to have raised beds or not) and put at least a couple inches of rigid foam so my heat wouldn't bleed out. Run a LOT of tubing, then use either solar or a wood boiler to heat my water ( or a combination ). In your climate, a double layer of plastic for sure....or maybe go with Solex, which is a flexible, double wall version of polycarbonate panels...comes in 4' and 6' wide rolls, or go with rigid polycarbonate panels, triple wall ( but get ready for sticker shock ! )
