I cant get my compost to heat up - Ask Extension
Hi! I have these lovely compost bins we built (pic attached). We made the bottom solid because critters are a problem and started filling one side abo...
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I cant get my compost to heat up #849774
Asked September 13, 2023, 1:06 PM EDT
Hi! I have these lovely compost bins we built (pic attached). We made the bottom solid because critters are a problem and started filling one side about 1.5 years ago and i just cant get the pile to heat up. I try to do the right brown/green ratio using foodscraps and lawn clipings and straw. Ive added chicken manure near the beginning and more recently and try to keep it moist. It gets turned weekly or sometimes a week is skipped now. At one point it was probably 3' high but it keeps decomposing back down and now its maybe 2' high but its broken down quite a bit so i was hesitant to add fresh stuff to it (im using the other side for that).
I have a compost thermometer and this pile has never broken 80 degrees! I just dont know what to do to get it to heat up so i can eventually use the stuff in my veg garden.
Any help would be appreciated, i didnt think it would be so difficult/take so long!
Washington County Oregon
Expert Response
Hello, Jennifer Conlon:
It sounds like you're doing everything correctly.
It may be that the problem is not enough nitrogen, since you are on top of aeration (turning) and moisture. You could deliver nitrogen though fresh green grass clippings in the spring, a nitrogen fertilizer. I recommend using old chemical fertilizers whose bags have been damaged or gotten wet, if you have such things. If you're going to purchase nitrogen fertilizer, I'd recommend 25-0-0.
But what I use myself is alfalfa pellets purchased at the feed store (you'd be looking for a 40 lb bag, rather than the small bags sold for pet food.)
Grass clippings should be turned into the compost while they are fresh-cut, or as they have begun to ferment. Chemical fertilizers should be dissolved in water - about 2-3 cups per 3 gallons of water. Alfalfa pellets should be sprinkled onto the surface of the compost as you're turning it - about 8 cups every 4-5 inches of depth. The pellets must be moistened with water before being covered with the next layer of compost.
I gave up that size of compost bin years ago because of the time required to turn that volume of compost.
But I have made great compost without its having heated up. The photo allows limited analysis, but it appears that you are making compost. Have you thought about adding red wigglers to these cooler piles?
It sounds like you're doing everything correctly.
It may be that the problem is not enough nitrogen, since you are on top of aeration (turning) and moisture. You could deliver nitrogen though fresh green grass clippings in the spring, a nitrogen fertilizer. I recommend using old chemical fertilizers whose bags have been damaged or gotten wet, if you have such things. If you're going to purchase nitrogen fertilizer, I'd recommend 25-0-0.
But what I use myself is alfalfa pellets purchased at the feed store (you'd be looking for a 40 lb bag, rather than the small bags sold for pet food.)
Grass clippings should be turned into the compost while they are fresh-cut, or as they have begun to ferment. Chemical fertilizers should be dissolved in water - about 2-3 cups per 3 gallons of water. Alfalfa pellets should be sprinkled onto the surface of the compost as you're turning it - about 8 cups every 4-5 inches of depth. The pellets must be moistened with water before being covered with the next layer of compost.
I gave up that size of compost bin years ago because of the time required to turn that volume of compost.
But I have made great compost without its having heated up. The photo allows limited analysis, but it appears that you are making compost. Have you thought about adding red wigglers to these cooler piles?
Linda,
Thanks for the suggestions. My garden soil gets amended w/ alfalfa so i can easily add some of that in. Its also really hard to know how much straw to add. My adding seems a little haphazard.
You said youve made great compost w/o its having heated up - i guess this would be 'cold composting'?! I havent read much on that. Maybe this is what im doing?! If, by chance my pile doesnt heat up - how will i know its 'safe' or ready to use on my veggies? I read so much about how its not great to use unfinished compost.
Best,
Jennifer
Well, let's call it curated cold composting.
I think true cold compost is made by stacking stuff up and then years later using it as compost. No effort made to turn or monitor moisture.
By safe, I think you mean from a nitrogen-tying up perspective, rather than from a food safety perspective. If unfinished compost were applied maybe 6-8 weeks before you started planting, that should give it some time to further break down.
Food safety: dog, cat, raw hog and human feces should never be applied to vegetable gardens. The eggs of parasites, the cells of fecal-borne diseases are very small. You can't be sure that each tiny particle has been rotated into the hottest part of a compost pile and held there long enough.
Don't overthink this. Composting is for fun! It's a pleasure! You're clearly creating a valuable soil amendment, whether it's perfectly perfect or not. Make compost and enjoy your gardening. :)
I think true cold compost is made by stacking stuff up and then years later using it as compost. No effort made to turn or monitor moisture.
By safe, I think you mean from a nitrogen-tying up perspective, rather than from a food safety perspective. If unfinished compost were applied maybe 6-8 weeks before you started planting, that should give it some time to further break down.
Food safety: dog, cat, raw hog and human feces should never be applied to vegetable gardens. The eggs of parasites, the cells of fecal-borne diseases are very small. You can't be sure that each tiny particle has been rotated into the hottest part of a compost pile and held there long enough.
Don't overthink this. Composting is for fun! It's a pleasure! You're clearly creating a valuable soil amendment, whether it's perfectly perfect or not. Make compost and enjoy your gardening. :)
Thank you so much! (and i never put feces in ;)
Love the tip of working it in 6-8 weeks before planting, i think that will really help!
See also this publication about using compost: https://extension.oregonstate.edu/catalog/pub/em-9308-how-use-compost-gardens-landscapes
ljb
ljb
