As the tital says, I’m looking at buying a 14-20x40 hoophouse with all the bells and whistles. Inflatable Second layer, roll up sides, double doors on both ends, Intake with HEPA filter and a matching exhaust (already have these). Debating the best source of heat, propane or a wood stove (I have an extra one). If I did a wood stove I would add a wood end wall and put my stove pipe out of that. My only concern with a wood stove is the heat that is generated vertically, and if it would be to intense for the poly…
May just end up doing a bad ass DIY one…I would do a walpini but my preferred location for this is near a creek and I wouldn’t be able to dig very deep without hitting water.
Let me hear what your guys experiences are.
Note: this greenhouse isn’t for cannabis, it is for year round food production and a place for me to teach my kids about gardening, etc… (they are homeschooled)
Best source of heat is actually infrared mats (on benches) or a hot water heated concrete floor. Prep the area, put down the pex maze, and top with a thin layer nonshrink grout like sikaflex. Could even use the woodstove in conjunction with a 12v pump to heat and circulate the water.
I have been greenhouse growing tomatoes and spring plant starts for about ten years. The most cost effective design is chain link top rail. You can buy a bender and hand bend it. I sometimes use 1.5" emt conduit elbows to connect straight pieces. You can saw a 90 in half to make a 45. Top rail is great, but it sucks for snow load. A heavy wet snow will smash a lot of diy tunnels.
Basically, anything clear has an abysmal r value. I started out trying to heat a double poly 14 x 48 structure with wood. The highest I could get above the outside temp was about 15 degrees. The chinese have what I think is the smartest design. They roll a tarp or straw mat down at dusk each evening, then roll it back up in the morning. Think retractable roof stadium. You want clear by day but insulated at night. Alternatively, it is much easier to heat low tunnels over your crops than to heat the entire tunnel.
You are welcome. I always love talking greenhouse stuff. With that much snow, I would probably look into a gothic arch design. I was into the idea for a while, but never built one. There is an ancient art of bending wood for ship hulls. It is possible to build a steam box for a piece of wood, firs work well, and after steaming it, clamp it into a frame to dry into an arch. A gothic arch structure is basically a ship hull turned upside down.
I designed my own GH and found eco done to manufactured/build it. They are located in Nor Cali. I would suggest you go polycarbonate (panels) 8mm or better. Gothic roof. If heat is hitting 100F ambient I would go with a slight milky light refraction polyeutherane or subterranean growing. Run cross gable ventilation with fans circulating in-between the exhaust and induction fan. Check out this site. Your wallet won’t feel dat burn
@Dirteagle I like that idea. Sounds more efficient than LPG heating. I’ve been doing extensive research on tankless recirculating hot loop pex maze. This was for process systems but I didn’t even think of applying it this way. You ever been on a site with somebody using them? I’m wondering how much extra BTUs will be needed if the grout is making thermal resistance.
No idea on the btu specifics, but it’s how a lot of year round operations in the mid atlantic get a 4th season out of a 3 season structure. Keeps the plants from freezing.
If you can spring for a moisture barrier and 2+inches of foam on the ground before the pex that will improve efficiency.
