When you’re hot, you’re hot!

For some time I’ve lamented that I never manage that seemingly perfect mix of compost heap ingredients that yields a little backyard furnace of thermophilic microorganisms, the one that keeps me from spreading weed seeds all over the yard (I’m damn tired of Arizona ash, sunflower and frostweed sprouts everywhere). I vowed to do better with composting this year, but wasn’t really doing anything systematically better to get there.

A week ago, however, I went to bury some kitchen scraps in the pile and flipped over a layer of organic detritus and discovered… heat!

Compost temperature

The temperature needs to be a little higher… 135-160 degrees is the optimal temperature to destroy seeds and pathogens (not that I suspect THOSE are a problem… yet). Could be I need to get more air or moisture – or less – into the mixture.

But I think I stumbled into the right mixture of “green” to “brown” materials for the compost heap quite on accident. And a way to reproduce it in a somewhat reliable way. Last week when I mowed the grass for the first time this season, I had a bag of scavenged mixed oak leaves and grass from another yard I was mowing near. The bottom of the bag had rotted out, and when I went to move it, the leaf mixture spewed forth. Did I bother to rake it up? No. I had my gas-powered vacuum cleaner already running, so I kicked the leaves around and mowed them up. Since it’s a mulching mower and I bag the clippings, I had inadvertently created a really good mixture for the compost heap, probably achieving close to the 30:1 ratio of carboniferous to nitrogenous materials.

But it has been exceptionally dry here, too.


So, to help with that, I’ve been allowing tap water to sit in white plastic jugs. This allows the city-provided chlorine to outgas and prevents it from damaging the microbial community in the compost heap. Every week I dump a 5-gallon jug into the heap to help keep it moist. I generally turn it (or at least give it a good prodding) on the same rough schedule so it maintains some oxygen.

Last night I checked the temperature again, and it had fallen to around 110?. I suspect a lot of the nitrogen-bearing grass has been used up. It’s getting close to time to mow again, so I’m definitely going to toss in more leaves as I do.

Leaf Supply

And if that doesn’t work, I might resort to peeing in my compost pile. 😉

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