Author Topic: Compost heating for greenhouse  (Read 1479 times)

Janpol

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Compost heating for greenhouse
« on: December 13, 2019, 04:22:39 PM »
Welcome
I need your opinions or advices about compost heating . From what you can read on the internet, it is really cheap and ecological way to provide heat. The compost inside can reach a temperature of up to 80 degrees C. Do you think that in this way in 6b zone in winter you can heat a small greenhouse of plexiglas and polycarbonate (about 2m2)? Of course, this is not about high temperatures. The idea is to keep the temperature in the greenhouse around 5-7 degrees C, suitable for wintering olives, pomegranates, citrus plants etc. I choose this option because for me it is not possible to connect electricity and coal heating is unhealthy and quite dangerous.It is an effective solution? I look forward to your advice.

Best regards,

Jan


Bomand

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Re: Compost heating for greenhouse
« Reply #1 on: December 13, 2019, 05:09:02 PM »
In order to provide energy compost has to be comprised of the right material. Has to be turnrd on schedule and kept at the right moisture level. It is a good way to keep a small enclosure above freezing unless you are in the Artic. I have a small cold frame that I heat with compost. It is a crude one but effective. It is an old bath tub with compast in the bottom and soil on tol of that. Its covered by an old window. Works like a charm. Notice what zone I am in

Millet

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Re: Compost heating for greenhouse
« Reply #2 on: December 13, 2019, 08:35:46 PM »
To warm a 2M2 (6-FT x 6.fT. ) wouldn't the compost pile take up just about all the greenhouse space?

Daintree

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Re: Compost heating for greenhouse
« Reply #3 on: December 14, 2019, 12:36:05 AM »
So, you are referring to "hot" composting, which is an accelerated process that generates a lot of heat.  I experimented with heating my greenhouse using this method.  It takes about about 4x4 ft of space, and the big problem I had is that you have to tend it all the time, get exactly the right mix of ingredients, and then, in the dead of winter, when you need to feed your pile, where can you get fresh grass cuttings, leaves, etc?  In order to generate enough heat to warm a greenhouse, that pile has to be going ALL the time. You will wind up with completed compost in just a few weeks, at which point the pile will "die" unless you get a lot of the material out and feed it with fresh.  The fresh material can't be frozen (i.e., from sitting outside waiting to be used) when you add it.
So, lots of space, lots of time and energy, and lots of storage for extra materials. But it DOES work, if you are devoted enough.
I wasn't, of course, and that is why I have a really nice blue flame gas furnace now!

Cheers,
Carolyn

Janpol

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Re: Compost heating for greenhouse
« Reply #4 on: December 14, 2019, 10:25:15 AM »
Gas heating is also out of the question. I would to pick up floor in the greenhouse, dug  and in arisen hole put compost. On it I would to put trellis and only then plants. What do you think about it?

Whereof is the best to make compost which give much warm?


« Last Edit: December 14, 2019, 10:30:55 AM by Janpol »

Daintree

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Re: Compost heating for greenhouse
« Reply #5 on: December 14, 2019, 05:32:36 PM »
Hi Jan!

I use the Berkeley method for hot composting.  Read up on it first, to see if this would work for you.  Just Google Berkeley Hot Composting. There are probably YouTube videos out there also. What you need to do and when is VERY specific. Below are some general guidelines.

I hope you are young and strong! You would have to move all the plants out of the way to turn the pile every other day.

The ratio is 25-30 parts carbon (straw, cardboard, dead leaves, dried grass, or paper) to 1 part nitrogen (grass clippings, manure, alfalfa meal, vegetable waste), and the ratio needs to be exact. The material needs to be shredded to the right size (you can't just dump in a bale of straw.  It would need to be chopped to about 1 inch pieces).

Moisture content needs to be about 50%.

You have to keep the temperature above 140 F (60 C) degrees fahrenheit, and below 160 F (71 C).  Any colder and you may stop generating heat.  Any hotter and the pile could combust when you turn it and expose the inside to air.

Every 18-21 days, you repeat the whole process with new material.

At 4 by 4 feet (and that is the minimum size needed to generate heat), that is a LOT of paper, straw or cardboard.  The nitrogen is easier - I used alfalfa pellets from the farm store. But they aren't cheap.

So, I am not trying to tell you not to do it.  Your idea of the pit sounds awesome, but I found Hot Composting on a continuous basis was WAY more work than it was worth, and really hurt my back.

Cheers,
Carolyn

Janpol

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Re: Compost heating for greenhouse
« Reply #6 on: December 15, 2019, 03:38:39 PM »
Hi
What if you put spiral pipes into the compost with an outlet on surface? Will there then be less work with heat distribution (in greenhouse)?

Daintree

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Re: Compost heating for greenhouse
« Reply #7 on: December 16, 2019, 02:05:36 PM »
The pipes would help with heat distribution, but it wouldn't make less work.  A big part of Hot Composting is that you HAVE to turn the pile, in a specific way, every two days. A regular compost pile, where you don't really have to touch it, just won't make enough heat, even with pipes.

lebmung

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Re: Compost heating for greenhouse
« Reply #8 on: January 13, 2020, 02:48:37 PM »
Better focus on conservation. The north wall should be very well insulated, add black water bottles, that temperature will reach easily be during the days.
At night you can use a paraffin burner. The only dangerous days are at night when there is a cold spell for few days dropping to -15 C. That is challenging for a such small place I would just put blankets over it for those days.

SeaWalnut

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Re: Compost heating for greenhouse
« Reply #9 on: January 14, 2020, 05:44:45 PM »
Better focus on conservation. The north wall should be very well insulated, add black water bottles, that temperature will reach easily be during the days.
At night you can use a paraffin burner. The only dangerous days are at night when there is a cold spell for few days dropping to -15 C. That is challenging for a such small place I would just put blankets over it for those days.
What do you mean by parrafin burner?