Heat For Greenhouse?

[big rockpile]

Would Wood heat be ok?

big rockpile

[MaineFarmMom]

Yes. It will keep humidity under control which helps control disease. I know a lot of people using wood heat with great results.

[CaliannG]

~smiles~ Or you can kill two birds with one stone.

Get a dehumidifier. In a greenhouse, you want the humidity to be low....the lower the humidity, the more the plants transpire, the more water, and not to mention nutrients, the plants suck up, the more they grow.

Dehumidifiers run hot...they are like having an electric heater in there.

So, in the course of doing one thing, you accomplish another.

[Belfrybat]

A large commercial greenhouse not too far from me uses propane in some greenhouses and wood heat in others. Their hoophouses are huge --
around 50x150' each, and they have a double barrel heater at each end. I'm told even though they are more work, they prefer the wood as it provides a better environment for the plants.

[Farmerwilly2]

I wonder what they're like to keep stoked through the night.

[MaineFarmMom]

Originally Posted by Farmerwilly2

I wonder what they're like to keep stoked through the night.

Everyone I know makes a trip out at night before going to bed and again around 3-4 am. Greenhouses don't have to be hot. I keep mine around 40* at night with tomato, pepper and eggplant seedlings.

[overthrow]

Originally Posted by MaineFarmMom

Everyone I know makes a trip out at night before going to bed and again around 3-4 am. Greenhouses don't have to be hot. I keep mine around 40* at night with tomato, pepper and eggplant seedlings.

I just finished my greenhouse and was hoping to heat it with a small airtight woodstove, assuming it would make it till daybreak. Hope Im right.

[Marcia in MT]

Greenhouses can be heated with all sorts of things -- just make sure the burn unit is airtight, as combustion products can hurt plants. And make sure there's a way for replacement air to get into the greenhouse, generally right at the burner or at the far end of the house.

[adamtheha]

What about a rocket stove, with the exhaust tube running down the middle of the greenhouse, piled over with soil or sand/gravel? I think the trick to heating a greenhouse with wood is to put as much thermal mass around the heater as you can. That shouldn't be tough with a greenhouse, it wouldn't need any foundation as you would inside a house. You could fire it before you go to bed, the mass would heat up, and release heat all night.
No way I'm getting up in the middle of the night to light a stove in a greenhouse.
If you ran some drain tile underground, right below the greenhouse footprint, you could pipe hot air from the top of the 'house during the warm of day, and reverse the flow at night, bringing that warm air back topside.
Incidentally, there are several people doing both of those things I just mentioned successfully in northern-types climates. One guy in Minnesota grows citrus inside a heavily insulated greenhouse whose only heat source is the ground, piping buried 8 feet deep.
Or, dig the greenhouse into the ground, the ground will hold the sun's heat all night long. Lot of work to build though. This is what I've partially built, just need to cover it with greenhouse plastic.

[Wolf mom]

Cold sink trenches work to keep cold air off plants. If you have room, 55 gallon water filled drums work well if the sun can reach them, although they shouldn't be put up against windows as you'll loose night heat.

A study in Flagstaff was done with 500 1 gal. water bottles stacked, and kept the greenhouse at a temp of 49.8 degrees with the average outside temp was 12.4 degrees. (can you imagine collecting all those bottles?)

If you haven't built it yet, make sure it's orientated within 10 degrees of South. There's lots of things that can be done without using an outside heat source. 2 good books have been mentioned on recent threads.

If you already have a standing greenhouse, I'd try to incorporate some of the solar greenhouse ideas to lessen the need for outside heat.

Have fun!

[Oldcountryboy]

Big Rock, how big is your greenhouse? I just read a old issue of Countryside magazine that had a story about this person who has a 20' X 96' cold frame. He claims he has two plastic covering over it with a fan installed to blow air between the two plastic covers. This insulate the cold frame better. He also has two chicken pens inside the front on each side of the walkway. He claims the chickens provide enough heat to keep the frost off the plants. The chickens also produce fertilizer and Carbon menoxide/dioxide(? the better one). His claim is that he can raise a garden almost all winter long but it will slow down in the coldest part of the winter as well as the hottest part of summer.

He also has a worm bin in the walkway to feed waste to and in turn gets to have worm casting to use.

[MoonShine]

Wood heat would be so nice. Mine is heated by electric and it's not good.

[willowworker]

Hi. Some up here in No Minn use outside wood burners to heat their greenhouse, house, garage, workshop, etc.....have the heat piped into buildings. Control how warm you would like it at the heat source. willowworker

[sticky_burr]

ok one add lots of therman mass ie clean 275 gallon and or 55 gallon drums painted flat black. filled with water insulate the bottom. there is also a rocket mass heater clean burn and stores heat in thermal mass and releases it slowly over night.
are you looking to totally change the atmosphere or just temper it a bit? add a bit of heat and lots of thermal mass

[Dexter]

Dry air also makes conditions perfect for spider mites, just a thought.

Some people I know used a woodstove in their house, that heated up water pipes that went through the greenhouse, then back for use in the house. They were happy.