early

Thoughts on heating a greenhouse

15 posts in this topic

I have had a south facing 12x24 foot double-paned glass lean-to style greenhouse attached to my shed for 5 years now, but I have never been real successful with it. My main goal has been to use it to grow through the winter, but have problems with maintaining warm enough temperatures during the cold winter nights. I'm in USDA zone 5. I have tried using black painted drums filled with water on the back wall and that has helped a marginal amount, but I've always ended up losing plants because of the cold nights unless I used an electric heater. I am not hooked up to nat gas and I don't have a propane tank. I am all electric. I would like to get this thing churning out vegetables in the winter without spending an arm and a leg heating it. I also have some problems on real sunny days in the winter with the GH overheating. It can get up to 120F during the peak of the day when its clear out and then I have to vent off a lot of that heat that I would have been able to use over night. The floor is poured concrete so I can't do much of anything underground. It's also far enough from the house that I don't want to have to go out late at night to feed a bunch of wood into a stove.

You good folks have any recommendations for how I can get this thing heated without spending a fortune or needing constant attention? Thanks for any ideas.

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I used something similar to this.     It's a different brand, but they are all the same manufacturer.  I used diesel fuel  to heat my 24' x 32' greenhouse as it was a lot cheaper than kerosene, but did smell worse.   WIth nightime temps in the 20's, it typically cost around $60 or so dollars to heat a month if I set the thermostat at 45F.   It's pretty loud though.

kellenw and early like this

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Hi Early,

I'd be looking at a rocket mass heater.  They are already used in situations like yours.

Have you considered a thermal blanket for the chilly nights and the hot extremes?

Gary

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Radiant Floor Heating.

By keeping the root zone at a constant temp. the air around the canopy can be way lower.

Same principle used by hunters during the winter, they use heated socks, gloves. Keep the extremities warm, that warmth is radiated thru the blood stream to the core of the body.

Using a simple setup of 100 l/f of 1/2" CPVC pipe and fittings, a 30 gal hot water heater, temp controllers, and a circulation pump, and minimal logistics materials, you only need less than 1.1 gal of water.

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Make a Winter Vegetable Garden Work for the CSA 

northern Wisconsin + 16-by-24-foot greenhouse + 70-degree, that costs less than $50 a year to heat.  

Imagine living in northern Wisconsin where winter temperatures are regularly measured in windchill. By January, one can’t help but dream of warmer weather, a winter vegetable garden and fresh-picked produce. Now, imagine bundling up and jetting across your yard to a 16-by-24-foot shed, throwing open the door and harvesting fresh veggies in a 70-degree greenhouse that costs less than $50 a year to heat 

early likes this

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Hi OP,

The article, while a nice story, actually said very little about how to construct a greenhouse, and even the link to the book that the site is trying to sell is broken.

My assessment.....1/10.....about as useful as tits on a bull.

Gary

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27 minutes ago, GaryD said:

Hi OP,

The article, while a nice story, actually said very little about how to construct a greenhouse, and even the link to the book that the site is trying to sell is broken.

My assessment.....1/10.....about as useful as tits on a bull.

Gary

early has a GH already, he just wants to heat  it, a cheaper way. The link worked for me, 10/10

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1 hour ago, Old Prospector said:

early has a GH already, he just wants to heat  it, a cheaper way. The link worked for me, 10/10

You're quite right.....my mistake.  What I meant to say was that the article contained very little information about heating a greenhouse....and the link to the book (the real purpose of the article) is broken.  Still 1/10.

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13 minutes ago, GaryD said:

You're quite right.....my mistake.  What I meant to say was that the article contained very little information about heating a greenhouse....and the link to the book (the real purpose of the article) is broken.  Still 1/10.

http://www.localharvest.org/elsewhere-farm-M7970

Contact Information

 

Contact
Clare Hintz
(715) 774-3153

 

Location
Elsewhere Farm16550 Nicoletti Road
Herbster, WI 54844
Edited by Old Prospector (see edit history)
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Thank you for the great ideas and suggestions! Ravnis - Did you have any problems with soot from that heater? Any ventilation concerns? Fire concerns? Something like that might be my best approach for now until I have the time to do some of the other things mentioned here that would help improve efficiency further so I was curious.

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@Old Prospector The radient flooring is a great idea and something I have wanted to do for a great while. Old man time keeps getting in my darned way though. I was thinking about putting down foam board insulation over the current pad, running radient lines and then adding another thinner layer of concrete over the whole thing. I can't budget paying to have it done so its all a matter of me finding that time I need to get 'er done.

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No problem with soot, but my greenhouse was not air tight being it was just plastic secured to  a wooden frame.   I used a carbon monoxide monitor in the greenhouse, but never got a detectable level above it's preset set point.   You will need at least 4 ft of clear space in front of it.  I had to tweak the fuel rate to keep the flames from extending past the metal casing.  I had an adjustment on it that could be set with a screwdriver and it took a little trial and error.   I've heard of models that output infrared heat that are supposedly more efficient, but have not really looked into them as this heater was easily purchased at a hardware or feed store.  You will need some method of ventilation if your greenhouse is airtight.  Carbon monoxide is no joke.

Also, don't overlook the importance of setting up a solar water heater to heat the water. Just keep in mind that heat loss from the water goes up as the air temp goes down. 

I had looked into the radiant heater thing, but could not justify the added expense in zone 8, but in 5 it might be worthwhile.  You could lay the insulation and radiant heating lines and build a wooden pallet type support over it to hold your system. You could make the wooden support rest on the concrete and the foam board cover the concrete in between depending on how large a system you built.

Edited by Ravnis
add caution about carbon monoxide. (see edit history)

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http://www.worldcat.org/title/northlands-winter-greenhouse-manual-a-unique-low-tech-solution-to-vegetable-production-in-cold-climates/oclc/435438027

That link will provide you with a way to get the book from a library if you wanted to read it before you bought it.   It sounds very similar to the Sunny John subterranean heating/cooling system.  Beware those type of systems loose efficiency in damp/moist environments typical of an aquaponic setup , so your mileage may vary wildly depending on local climate and solar exposure.

For your convenience a link to solar map is provided.

The link that OP posted did have some useful information, but it's not spoon fed and was really similar to the preface of a book. The name of the book is provided and a simple google search yielded multiple hits.

Edited by Ravnis (see edit history)

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Hi Early,

Hace you considered something like the Jean Pain method?  Murray Hallam has just done a video where he buries a heap of plastic water pipe in a large compost heap (contained inside a corrugated water tank).  You have to provide an email address to access the video (and a heap of others like it) but it might be worth a look.

As the compost heap heats up (begins very quickly and persists for months), he pumps water through it.  The temperatures that are produced by this method are quite amazing.

Is this a possibility for your location?

Gary

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