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Composting in a greenhouse. Symbiosis?  RSS feed

 
jeremiah bailey
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Brenda mentioned, in another thread, that she has her greenhouse over a natural heat source, her septic tank. I had just finished checking on my compost pile when I read this. Wouldn't it make sense to make a compost pile in the greenhouse? The greenhouse harnesses the sun energy and acts as an insulator. The compost pile provides extra heat and compost for the greenhouse. A quick google showed me that this is actually commonplace. Has anyone here heard of or done this?
 
Leah Sattler
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I have heard of using manure to heat green houses (as well as other structures) and thought it was a fabulous idea. the heat generated from a large compost pile is immpressive. when I was a kid I would always go sit on the giant poo pile in the winter. you could carve yourself a little wallow in it and be toasty warm.
 
Brenda Groth
pollinator
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Location: North Central Michigan
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well my greenhouse is very small so it really doesn't have room for composting per se in it, however, i do put down manure and stuff in there..building up the soil and when the plants are large enough i can mulch them as well..

the pipe from the house comes out under where the boardwalk is and the first lid to clean out is in front of the greenhouse..of the tank..and the second lid is inside the greenhouse..(easy to find them)..the greenhouse is wider than the tank, but shorter..so the soil has to be built up some to plant in, most of the garden isn't growing much yet as we are still having hard freezes..27.7 degrees sunday morning.
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my mixed baby greens are in the shade of the porch where they are so they should last quite a while..there are baby cabbages and stuff in there but aren't big enough to see yet..inside the greenhouse are transplanted peppers and tomatos as well as those direct seeded in the ground..the direct seeded only have about 6 sets of leaves so far so they aren't too easy to see, they are around the outside edges..

there are peppers on a few ..3 or 4...of the transplanted pepper plants, but the seedlings direct planted have no flowers yet..generally we can't set out plants in Michigan until about June 8 or 9..after the full moon.

you might be able to see that the frost did nip the marigolds outside the greenhouse some.
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I finally got a drip irrigation system set up again to water inside..you can see where the one candle burned the baordwalk..another one scorched some plants..(husband's head injury)..
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this drainfield is a raised system about 60 feet long..and we put a lawn over the leachfield and then we brought in fill from our field (which made our little pond) and we planted around the leachefield where it slopes to the main level, with all kinds of perennial plants, shrubs, trees, and vines..you might be able to pick out a few of the baby fruit trees in some of the photos..remember this garden isn't very old as we put it all in after our housefire..so it was just started in 2003..and we have been working on building it up since then..also a lot had to be redone in 2007 after son moved and we lost our raised bed garden and orchard then.
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there is a path going down to the main  yard on both the east and west side of the greenhouse end of the drainfield, and then  under the grape arbor and beyond there is a small deck with steps going to the North to the berry and nut gardens with the perennial food crops, and a grass path going down to the pond.

that big apple tree has lost all of it's blossoms now.
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these two photos are behind, or NORTH of the greenhouse, the flat lawn is hard to keep green as the leachfield is dry..and sunny..but the gardens around the leachfield are very nice and fertile..of course they are babies in Michigan now, and most of the perennials still have their heads in the dirt..waiting for warm weather.
 
Brenda Groth
pollinator
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Location: North Central Michigan
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sorry didn't realize the one picture was on there twice..oh well..i also try not to water the lawn on the drainfield ..so ..it does tend to scorch in hot weather..but it is fairly healthy right now..the rest of our lawn is like a jungle..as we are on a very high water table..that is why our draifneild is raised up 4' above the surrounding area..we have water that literally bubbles up out of the ground in some places on the property..and right now there is standing water in some areas..besides the pond (which you can see in this picture a little) beyond the leafless still catalpa tree
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here is a more close up of the pond...which you could see if it wasn't full of cattails already..the North end which isn't visible had a deep spot without cattails.
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paul wheaton
master steward
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Location: missoula, montana (zone 4)
bee chicken hugelkultur trees wofati woodworking
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Putting your greenhouse over your septic tank is brilliant! 

I remember reading the greywater book  (an excellent book that really changed my mind about a lot of things - I am now far less skeptical of greywater systems) and it suggested that for cold climates to route your greywater to a greenhouse.  Similar idea?



 
paul wheaton
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Location: missoula, montana (zone 4)
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A compost pile in the greenhouse can be a good idea.  I think the only issue could be that you could have a breeding ground for a swarm of bugs.

 
paul wheaton
master steward
Posts: 21356
Location: missoula, montana (zone 4)
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Brenda,

Septic tanks will sometimes release a bit of methane.  Does it ever smell funny in your greenhouse? 

I wonder if your candles might bring you some greater adventure at times! 

I suspect that accessing the tank to empty it won't be a big deal, but when the time comes, maybe you'll send us some pics of that too?

 
Brenda Groth
pollinator
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Location: North Central Michigan
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the cover to the tank..actually there are two..one is outside of the greenhouse under the boardwalk, and the other is under some tomatoes in the back..i can feel the lids when i flip up the boardwalk or work my hands into the ground under the maters..so i know right where they are..we had our tank pumped last year, to be on the safe side we keep it pumped out every 4 or 5 years anyway.

yeah i did wonder about the methane blowing up with the candles..but no ..no smell, no problem, we have automatic vent on the roof of the greenhouse..and we open the doors if it is 40 or above outside..as well
 
jeremiah bailey
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I imagine if a substantial methane leak would occur while the candles are burning, they'd oxidize the methane before an explosion hazard occurred. I'd just make sure to vent well before lighting/introducing the candles. This seems to be what you've been doing.
 
                  
Posts: 27
Location: Seattle
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I've learned from professional greenhouse growers that composting in a greenhouse can be good, not only for generating some extra heat at the margins of the growing season when a little extra heat helps, but also for off gassing CO2.  As CO2 levels in the greenhouse rise, so does plant production.  Some try to achieve CO2 levels @ 3000 parts per million.  Evidently there are gages one can get to measure such things.
    Regarding bugs...  yes, pests can be a concern in a greenhouse environment but micro-organisms are favorable.  Composting is about micro-organisms.
    Some growers are particularly careful about what materials they bring into a greenhouse environment because it is, after all, something of an "artificial" environment--it does not receive rain from the sky or other "cosmic" influences directly (like small amounts of meteor dust that sprinkle down on the planet)--the roof of the greenhouse prevents this.  What you bring in is what is there...  hopefully it will contribute to proper soil balance...  The pros use extensive soil testing to attempt to measure what they are working with...  They also test their compost!!!
    It has been said that 70% of the problems in a greenhouse derive from excessive watering...
    Proper ventilation can be key also...  just opening the door on a hot morning when the inside temperature in the greenhouse is 90 degrees can subject the plants to a vapor shock--colder 60 degree air that might rush in and hit the plants will contain less moisture and this can damage the sensitive growing tips of some plants (cucumbers are one such sensitive plant).  This damage may not show up for weeks and may only be expressed as failure to flower.  Sometimes the damage can be more directly observable but the connection is often not made to the fact that the plants were "shocked" with cold dry air two weeks ago--"they're failing but I don't know why..."  It's best to try to "mix" the needed cooler incoming air a bit before it hits the plants.  Some suggest ventilating from the roof, if possible.
 
Brenda Groth
pollinator
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Location: North Central Michigan
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my greenhouse has a heat activated roof vent..so it opens when the greenhouse gets at all warm, and then we open the door when the temps begin to rise outside also..so it gets a good exchange of air.
no room for compost in there..and that's ok..would rather not use my precious greenhouse space for that when it does fine outside.
 
                  
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Location: Seattle
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    I have forgotten who it was that has published a description of this technique, but I recall hearing of a woman who set up a system where she used 1/2 of a hoop house to house her chickens.  Their manure would be left to compost and the heat generated was vented into the other half of the hoop house to provide heat.  When the composting was complete, this was added to the planting beds...  My memory is faint on the details...  I do recall that there was one issue that needed to be resolved before this system could be effective--she had to figure out a way to filter the ammonia out of the air as this would build to toxic levels and would interfere with the plant growth...  but I understand that she was successfully able to do this.
    Sorry that I'm short on details...  maybe I can find a reference for this.  If someone is interested in learning more, perhaps they could research this idea further...  Perhaps someone out there is already familiar with this work and could do a better job of reporting than I...
 
Brenda Groth
pollinator
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in the first permaculture book i bought, they had the nesting boxes from chicken under the shelves of a greenouse..the greenhouse on the s..chicken coop on the north..

makes sense..

mine wouldn't work that way although I would LOVE to have some chickens, hubby won't allow..probably the first thing I'll do if he passes before me is get me a dog and some chickens !!!
 
Robert Ray
gardener
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I compost in my greenhouse. I purchased the largest red clay pot I could find and a red clay saucer that fit over the top. I bored several more holes in the bottom with a ceramic tile bit and placed that in a large low red clay container, blocked that drain hole with screen and filled that with potting soil. I plant lettuce and spinach in the base and have red wigglers in the central pot and fill it with my garden and kitchen waste. The pot is massive enough the worms don't die from heat and haven't yet died from freezing. Excess water drains into the salad bed and it requires a minmum of watering. There is the difficulty and mess of removing the composted material but it is easily spread in my greenhouse beds. If a worm escapes all the better.
Robert
 
Max Smith
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Dan McCoy wrote:    I have forgotten who it was that has published a description of this technique, but I recall hearing of a woman who set up a system where she used 1/2 of a hoop house to house her chickens.  Their manure would be left to compost and the heat generated was vented into the other half of the hoop house to provide heat.  When the composting was complete, this was added to the planting beds...  My memory is faint on the details...  I do recall that there was one issue that needed to be resolved before this system could be effective--she had to figure out a way to filter the ammonia out of the air as this would build to toxic levels and would interfere with the plant growth...  but I understand that she was successfully able to do this.
    Sorry that I'm short on details...  maybe I can find a reference for this.  If someone is interested in learning more, perhaps they could research this idea further...  Perhaps someone out there is already familiar with this work and could do a better job of reporting than I...


http://www.windward.org/internship/solviva2.htm
http://www.solviva.com/visit_solviva.htm

Her name escapes me, too, but her invention was the "Earth Lung," something she pioneered as part of her Solviva project. Really hope to replicate this some day...but I'll have to keep the biological moderating effects of a good Montana freeze in mind...evidently extending the season and creating that artificial environment you spoke of can be a real hazard if certain populations build over an entire year or two and are not exposed to all that our winter climates have to offer.
 
Zach Weiss
pollinator
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Composting in a greenhouse is a great idea. Usually greenhouses have pretty minimal air flow compared to outside. In greenhouses without compost this can lead to CO2 depletion, the plants use all of the CO2 around them and don't have access to more. If plants do not have CO2 they are not able to photosynthesize. Commercial growers will sometimes supplement CO2, as increased CO2 levels can lead to increased production. Ambient CO2 ppm is around 300-400. Most greenhouses don't enrich CO2, but the ones that do often only go to 800 ppm. Above 1800 ppm it becomes toxic for some plants and above 3000 ppm is toxic to most. I don't recommend getting your CO2 levels this high, it causes quite an unnatural atmosphere and the bugs go wild. The plants are growing faster than they should, and the pest bugs exploit that.

Back in the old days, when people had to provide their own food, they would fill cold frames with manure and bedding and then a layer of soil on top. The heat generated by the manure bedding mixture kept winter greens warm or helped sprout seeds early. This was all done by hand, but was still work the work for what it was able to produce. In the 1970's in France Jean Pain used compost piles to generate all of the heat for his house and greenhouse. He also produced all of the biogas for his automobile, tractor, and cook stove.


Compost Power

Having compost right inside the greenhouse, on the soil floor, is an absolutely wonderful idea. At the Ott-Kimm Conservatory this is how we have kept the soil productive for over 30 years without any chemicals, fertilizers, or external inputs. Notice the healthy layer of prunings and fruit feeding the soil surface of the nectarine below. This is our fertilization system for the greenhouse and with these methods it has become more productive with each passing year. The plant produces fruit not only to proliferate but also to condition it's own soil. The sugars feed the microbes in the soil and the carbs feed the fungi. If you let nature happen things taste so much better



Rainwater is also essential to the system. As Dan brought up soil inside a greenhouse does not receive rain unless we provide it. The acidic pH of rainwater is very important for the de-mineralization cycle in the soil. If you only use well water in a greenhouse the salts will build up and it will lead to big problems. Particularly in places with limestone or other rock types that lead to salts being present in the ground water. In places with granite or volcanic rock formations this is sometimes not a problem. When the pH of water is below 7 (rainwater is 6.3-6.5) then when it reacts with the rocks in the soil it releases minerals into the water solution. These minerals are then available to bacteria that in turn cycle the nutrients, making them plant available.

In the conservatory the compost on the floor raises the CO2 in the greenhouse to roughly 100ppm above ambient CO2. This is pretty good considering that in a greenhouse like this you would usually have much lower ppm than outside. This means that the compost on the soil surface of the greenhouse is producing all of the CO2 that the plants need and then some. If you want to use compost to heat a greenhouse the pile will have to be outside. Supplemental heat is fine, but piles that generate enough heat will produce too much CO2 and it will become toxic for your plants.



If you don't let nature take place and balance the insects of the greenhouse you will always have problems with insects, even without a compost pile in the greenhouse. It is best to work with them and come to a solution that works for all parties. Running a dormancy is a good idea for people getting into natural pest management. The dormancy provides the important winter rest for the plants and helps to balance out any insect extremes.

 
Nick Kitchener
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Location: Thunder Bay, Ontario, Canada
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Quite an extensive study was done on compost heated greenhouses including designs back in the 80's.

The composting is generally done in an insulated enclosure separate but adjoining the greenhouse. Heat and gases are exchanged with the greenhouse via vents and piping.

Here is one from the mid 80's:
http://www.builditsolar.com/Projects/Sunspace/NewAlchemycompost.pdf

Another from 2009. It only deals with heat and is based on the earlier work, but it does go into a full breakdown of materials costs etc:
http://uwaterloo.ca/environment-resource-studies/sites/ca.environment-resource-studies/files/uploads/files/CGilson490s.pdf
 
Brian Hamalainen
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Location: Chimacum, WA Sunset Zone 5, USDA Zone 8B
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My high school science teacher spent several years on a commune somewhere in Arizona. He said that they had a small stream running through the property. They'd run ambient temperature stream water through several steel pipes buried in their compost heap and get scalding hot water out the other side, year round. That is what I call "HOT composting"!
 
Nick Kitchener
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Location: Thunder Bay, Ontario, Canada
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There is a French guy called Jean Pain
http://en.wikipedia.org/wiki/Jean_Pain

He heated his entire house like this
 
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