I live in northern minnesota, just finishing up the last bits of our deep winter greenhouse. (this is the nicest december weather i’ve ever seen, lolz)
anyways, we have a woodstove moved in for heating at night, but there is no winning the battle against night temps seeping in through the poly.
we have a triple wall polycarbonate se face, 24×32. looking for suggestions for a diy blanket canopy of sorts.
has anyone faced this problem? any suggestions? we’re talking about doing an insulated tarp, emergency type blankets, rolls of insulation, even wool or something. looking for it to block wind, keep the heat in, and be pliable enough to withstand a lot of up and down. photo for tax !
by coolasagiraffe
13 Comments
[deleted]
I hope you find a good solution. Have any inside pics you can share?
Beautiful building. Many of us have more questions than quality answers. Please tell us about what current insulation you have in the building, under or around the building. I would work on retaining the heat, rather than just loosing it from all sides.
External wind brakes is an affordable idea to stop windchill from seeping in. Hay/straws stacked to the side of the building will do that for you but may bring in pests etc.
Rolling roof covers similar to Chinese style greenhouses are not common here but something I’ve been looking into. If a custom roof cover be swapped to summer shade cloth, this system maybe worth the build out. Currently the holidays have stopped by r&d on my custom rolling roof cover setup but I’ll share once I start up again.
No specifics for you other than he bought the whole kit from China, but might give you some ideas. He also responds to questions on his YouTube so might be able to help you out more. https://youtu.be/EHbaW1Ea_O4?si=CBy23AjGErlQrPIV
based on limited info, you probably have a few options.
increase solar gain: first photo looks like there is shade on your glazing, could cut those trees down. ooofda.
increase thermal mass: could add water barrels. paint them black. you could do a BTU calculation based on specific heat, how many, and expected temperature swings to see how much heat they could release overnight.
increase insulation / decrease heat flow out: i can’t really see what you have in your walls and roof. if it’s not over 20 or 30 you’re gonna have a hard time. if you are well insulated there you could address the glazing. one option would be to use the natural stud bays you have to make pockets of air. you could use translucent 6 mm poly and staple it on the underside of those stud bays. those would be totally sealed, but you could also put a small fan and some kind of connection between the bays to move the inside air through them and prevent a humidity problem or something.
decrease the volume of air to be warmed: if you look at the market garden youtube they have small knee high tunnels they put over row crops and pump heat into them, essentially using the volume of air above that small volume as an insulating blanket.
Air sealing is always the no. 1 priority. If you’ve got drafts or air seeping in, that’s going to be the biggest impact.
Could toss some r-10 polyiso or xps on the sidewalls. I’d be hesitant to use fiberglass/cellulose due to moisture in the structure.
Not sure who the best supplier is but, greenhouse thermal insulation quilts for the top at night. [https://www.alibaba.com/product-detail/Greenhouse-Agriculture-Thermal-Quilt-Blanket_1600095837249.html?spm=a2700.7724857.0.0.7ed16c7c3PjsfR](https://www.alibaba.com/product-detail/Greenhouse-Agriculture-Thermal-Quilt-Blanket_1600095837249.html?spm=a2700.7724857.0.0.7ed16c7c3PjsfR)
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UMN has some good articles to read: [https://extension.umn.edu/growing-systems/deep-winter-greenhouses#design%2C-construction-and-operation-2066620](https://extension.umn.edu/growing-systems/deep-winter-greenhouses#design%2C-construction-and-operation-2066620)
Oh my gosh this is amazing! I am in MN as well and would love to build something like this someday. Do you have your pans available anywhere?
This is awesome! You can get high quality canvas tarps that have metal eyelets (can tie them together) on Amazon for fairly cheap. Maybe you could line them with thermal blankets to reflect the heat back inside the greenhouse? I’d love to build something like this one day
i’d walk around with a laser thermometer and seek out areas that need to be insulated. insulate anywhere and everywhere you can. i’d also deploy some type of tarp over the poly but i’d think that insulation of the 3 layers should be enough already, but there is also the option of spending some money to setup a biotherm heating system. i’d check out their brand and website they make some small scale systems that can link up to a water heater to provide hydronic heating to the soil/ground/racks for your greenhouse. they might be a good investment for you
Maybe a pool cover you could role out and role back in . Also maybe a large amount of water that’s heated .
I’m my greenhouse the ground is the big loser of heat.
https://youtu.be/ZD_3_gsgsnk?si=rA4NfTDcGviDM7ns
Concrete curing blankets… buy a bunch and “sew” them together using galvanized 14d nails.
You’ll need a way to pull it up to the ridge and let I’d drop down a daylight…