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Heating My Compost Organically

Hi All,

I recently took a few minutes to build a home composter but I've run into a problem. We live in the Bay Area, in a shaded community, and rarely does it get warm enough to bring the compost pile to an acceptable temperature. Does anyone have a suggestion as to how I can artificially increase the heat of my compost pile, bearing in mind that this is to be done in an organic way? Thanks! Love the forum!

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Re: Heating My Compost Organically

the proper mix of "greens" and "browns" creates the biological activity which generates the heat.

no "sun" required.

the trick of course is to have all the right "composting materials" available at the time you want to "assemble" the pile. browns keep; greens do not keep.

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Re: Heating My Compost Organically

In theory, the proper mix of greens and browns will do it. But in 25 or so years of making compost, I must have never hit this happy mix. :( I've lived in Berkeley and now El Cerrito that entire time, neither known for its exceptional warmth or frozen tundra, and the only locations for my BioStack have been shaded.

My compost thermometer, when I've taken readings, has gotten me quite excited when it's hit 100 degrees F (38 deg C). Well, a thermophilic pile is 120-plus (48 deg C), so I have always made compost the cold way.

What this means for me is that I don't compost pernicious weeds--they won't be killed "dead enough," nor will their seeds. No blackberry vines! No English ivy! But an amazing amount of stuff *does* go into the compost bin. :)

Cynthia H.
Sunset Zone 17, USDA Zone 9

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Re: Heating My Compost Organically

I agree with Cynthia on watching what I put in my bins. Since I live in a subdivision and do not have the luxury of space to compost hard to compost tough greens (that really sound wierd) I cut stuff small. My compost bins are at the mercy of Mother Nature. I do every thing I am supposed to do - balance browns and greens, use manure, stir and toss, water. Some times my bins get really hot but sometimes they don't. I do have to say that even the coolest part of the bin has compost suitable for use in the garden.. Not completely broken down to soil but fine enough to be a wonderful additive to my beds and garden.

Composting is one of those things that you can play with for years! NO ONE has ever created PERFECT compost.

Good luck and just relax and have fun with your compost.
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Living and growing in Lafayette, La.

When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant. ~Author Unknown

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Re: Heating My Compost Organically

>>in 25 years

well, in my 40 years - I gave the flipping up on it.

I put it all in a heap and wait for it to rot down / decompose on its own schedule.

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Re: Heating My Compost Organically

The pile does not have to heat up to make compost, so I wouldn't worry about it too much.

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Re: Heating My Compost Organically

Add more greens. I don't have leaves right now so I am using newspaper torn into strips over the winter. It's working well. When I put my kitchen waste on, I reach in and get a handful of grass to put over it. It is hot.

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Re: Heating My Compost Organically

Dillbert wrote:I put it all in a heap and wait for it to rot down / decompose on its own schedule.
Nothing can be more organic than that, eh?
;) hee hee

Anyway, I didn't know people actually deliberately tried to speed the process along in their back yards.
Very interesting.
If anything, I've been surprised at how quickly stuff kind of just disappears or becomes unrecognizable.

But my heaps are sitting in the sun. The older of which is encased on 3 sides with 2-high cinder blocks - which my husband put there because he thought that was a good idea.

Could be that heats up quite a bit in the sun, what with the cinder blocks conducting & storing heat?
Northeastern Pennsylvania
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Re: Heating My Compost Organically

there is a valid theory to the "let's make HOT compost!" - the "heat" - should it be achieved - can/may/should kill weed seed and some perhaps unwanted bacteria.

but "perfect" can be a bit of a chore. have the right materials at hand, mix in the right proportions, keep it properly moist / not wet / not dry, aerate regularly.

or, toss it in a heap and let it rot.
I've had my 'piles' in full sun and in full shade; don't really see much difference.

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Re: Heating My Compost Organically

Hot composting is hard to achieve unless you hit on the right formula of greens, browns, and water. If you built your composter to handle a 3 x 3 x 3 ft pile and you build it all in a day or a week. If it gets up to temperature and starts smoking in a couple of days you have achieved success at hot composting. If you are really good at turning the pile every couple of days you can have compost in a couple of months.


Most people though, don't have the 30:1 C:N, just right and piles are usually built slowly over a longer period of time, so they really are cold composting. Unless piles are turned frequently, compost can take a year to finish. At some point you will have to stop adding to the pile and start a new one. That is why a three bin system is better than one or two. You cannot add diseased plants, weed seeds, or perennial weeds to the pile because they will likely not be killed. Manures should be hot composted to kill harmful pathogens, otherwise they need to be aged.
Happy gardening in Hawaii. Gardens are where people grow.

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Re: Heating My Compost Organically

I agree, when we are talking about hot composting, the heat is generated by the composting process, not added.
Sun or shade doesn't matter much.

I also have a pile that I just keep adding to as stuff comes along, that does not heat up very much. I don't add manures or other very high N stuff to it. I have noticed that when I add a bunch of duckweed skimmed from the pond (also a very high N source) the pile does heat up and "smoke." So if you want to be doing hot composting, I think having a very rich N source is part of the key. But a compost pile that doesn't heat up very much, still decomposes and makes nice compost. Just takes a little longer, but for me in the growing season not a year, more like 4 - 6 months.
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Re: Heating My Compost Organically

When I want to go hot composting I go back to the basics and I find it helps to visit here:

For a good list of greens vs browns I go here:
https://compost.css.cornell.edu/OnFarmHa ... taba1.html

Down here in So Cal we've got no shortage of sun. Funny thing is the sun is one of the things that dries out the compost pile. No moisture and hot composting stops so I have everything in the shade.

For getting the mix of browns and greens, I check out the list above and grass clippings is about the greenest thing I can come across and saw dust about the brownest with pretty much everything else in between.

For hot composting, I assemble everything at once for a total pile and only add soon after forming the bin. I plan on turning once a week. When I get it right, I adjust very little and get compost in a couple of months. Less successful attempts take longer.

Plan B is to pile it up and keep it moist and let the worms take care of the pathogens for 18 to 24 months.

One path takes more work and care and the other requires more time and space. That's your basic trade off.

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