I’m good n baked this morning and although the water is frozen outside my house im thinking about setting up my shitty pop up greenhouse.
I had a quick stoner thought. I have a 55 gallon drum of rain water for my carnivorous plants. What if i put that in my green house with a sous vide to help maintain temps at night.
Am i just crazy. Not worth the risk?
Anyone want to encourage this or entertain the idea?
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were i live north shore of lake Erie you would have to sell a kidney at the end of the month to pay the hydro bill. i have a few cattle panel hoop houses home made have tried heating them different ways. always kept going back to a hot mess of compost in the middle of the house it is messy but it works one thing i did learn is a layer of plastic will move you one grow zone south for example it is 4c 40f or so was a cool night for us -5 its non here and the house with three layers of 6 mill poly is 22c or around 70f i grow leafy greens in it all winter salad mix i have black mulch all around the area inside and out helps with the sun warming things up for me i will move my seedling out soon same idea in self watering 5 gallon pail with a plastic dollar store dome and a couple of those clear trash bags the big leaf kindi used to have a couple of those wire bag holder opens things but someone stole the works last june pails plants plastic the works
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Savage, buddy! 
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i’ll bite. on the fence about pursuing my own, so i’ve done a fair bit of research on climates similar to mine (zone 4a).
what do you plan to grow in there in the colder temps? if you go with frost tolerant varieties you will have a lot more success. if you plan on growing anything that isn’t frost tolerant, i think composting is the safest solution. i’ve seen ‘diy’ sand batteries which use vegetable shortening as a fuel. then you have a small copper diffuser to infuse the heat into the sand. typically they get up to 600F and will last for weeks. it is an open flame though so take that for what it’s worth.
typically any successful northern greenhouses will have heavy insulation on the north wall with most of the sunlight entering the greenhouse from the south side. if you don’t have any insulation night temps will be harsh.
additionally the greenhouses may be sunk into the ground for a geothermal effect. this is the best options for maintaining night time temps with the most minimal inputs.
there literally aren’t limits to growing anything in a geothermal greenhouse. i seen fruit trees growing in Dec/Jan in Michigan. also seen bananas growing in Colorado at 7200ft.
anything is possible, if you have the know-how. that’s the rub. 
p.s. i can send a ton of YouTube links if you’d like to see.
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i live at sea level on the water. If i dig 20 inches its sand then after 3 feet its water. 
The plan is to use it for photos that need about 3 weeks to finish up. / Put some Autos in that are started indoors.
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sea level on the water… sure know how to shoot for the stars… 
i would write off geothermal because of your water table.
if you have an abundance of sunny days there, a climate battery (mentioned above) is probably the best option, right behind an active compost pile. compost piles are nice because you can get massive amounts of heat while creating nutritive soil. the climate battery could be sand or water, basically anything that will absorb heat from the sun during the day. at night when temps drop, the climate battery will use the law of equilibrium to keep inside warm. again, the more insulation you have, the better off you are.
using it for canna… hmmm… i’ll have to think on it. i have similar ideas and desires.
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that there be ocean water last December
im looking at solar panels now to potential run a heat sources off my jackery.
im looking at solar panels now to potential run a heat sources off my jackery.
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mechanically speaking, it’s quite inefficient to convert thermal energy to electricity, then back to thermal energy. you’ll find the cost of such an endeavor isn’t practical, when you look at panels, invertors, batteries, and heaters. you’re better off trying to use a medium to capture the heat and maintain it through the night than capture electricity to turn into heat.
in my opinion the most efficient method would be to use a black-painted reservoir (quite large) then you could also make some ‘diy’ pond heaters to further increase water temperatures. plants could sit on top of the reservoir, which will radiate heat mostly upwards.
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I hear you i will wrap my water tank in a mylar blanket or possibly paint it black.
With Sous vide in my water reservoir powered by a jakery. The only thing I dont own is the panel itself. I can get a 220watt panel for 180. I understand that plugging a heater into my wall outlet is way more practical.
I wont be gaining anything except a couple of weeks of extra time. But i will still own everything.
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I’ve heard of several farmers using compost piles to generate enough heat to keep temperatures up during winter. I think it would be a lot of work, and you’d need a BIG compost pile. But… maybe worth it?
Here’s one sample video. Might be a worthwhile rabbit hole to dive into?
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It’s not too bad if you dig it in, that’s definitely an old New England gardeners trick for cold frame growing. I have some books on the shelf with diagrams like this to do manure heated cold frames, I had an old couple down the street from me growing up who had the old farmstead on that section of road, still had horses, but without fields they would fill a dumpster with the fouled bedding and in the winter you could see the heat waves radiating off of it, melting any snow and ice within a foot or two on the ground around it.
https://extensionee.missouri.edu/publications/g6965
They’re called hotbeds when heated with a power source or the heat of decomposition, most of those beautiful Victorian glass hothouses either had manure hotbeds or the ancient cross floor flue setup with a wood or coal furnace underneath that was fed by the house servants:
Can’t find access right now without a library card but that’s pretty easy:
From Manure to Steam: The Transformation of Greenhouse Heating in the United States, 1870-1900
This is accessible and a much bigger overview:
hortsci-article-p239.pdf (1.4 MB)
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If you live in a wooded area you can install a wood burning boiler, running hydronic lines through your beds and running lines through a blower for space heating.
People do this in Alaska during the shoulder seasons.
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If I was trying to get through a shoulder season and finish plants, or get a jump on the year, I would opt for a rocket mass heater and just accept feeding it for that month or two a year like some people pull tarp for light deprivation greenhouses. Just like that, this can get automated too by using a pellet stove with a hopper and automatic feed. If you can get away with it where you are, legality and neighbors are the big issues.
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bit of overkill for op’s little portable greenhouse… lol…
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heating the water in a barrel?? don’t know how well it would work… set it up and try plugged in for a few day’s and moniter the temps… only way to really know is test out your brainstorm… if it works or not, let us know
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Those are just to demonstrate the idea, lots of people make them out of a beer keg or a small barrel for the firing chamber and piles of large rocks for the mass, just surrounding the barrel and flue like a trail cairn
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The wireless thermometer I bought is an unreliable piece of junk. So I dunno the temps out there. The nights have been in the 40s.
The sous vide brings the water on the top of this barrel up to temp but its too much volume and the top and bottom of the water dont equalize fast enough. I had to add a submersible pump that goes on 15 mins an hour to stop the sues vide from cutting off. I have a bunch of almost finshed plants out there as guinea pigs.
