My Compost Isn’t Breaking Down: What Do I Do?

 My compost July 21 (left), on April 15 (top) and December 26 (bottom).

My compost July 21 (left), on April 15 (top) and December 26 (bottom).

What do you do when your compost isn’t breaking down? I’m still trying to figure out the mystery that’s going on in my composter. Can you help? 

Last year, I decided one of my 2017 garden goals would be to get into composting. When I started asking for advice, I heard that I shouldn’t overthink it. I only needed to get a container, throw stuff in it and nature would take care of the rest. I’ve found it to be a bit more difficult than that. 

In October, I bought my composter: an Envirocycle tumbler. I thought about going with an old trash can with holes drilled in it, but decided to go with the option that looked best and was designed to tumble.

In went some fall perennial clippings. I also planned to continue adding food scraps through the fall to keep a balance of green/brown (also known as carbon/nitrogen). We added egg shells, vegetable peels and a whole lot of coffee grounds and started turning that tumbler.

Keeping A Good Carbon/Nitrogen Ratio

Somewhere during the winter, I realized that I probably hadn’t kept a good green/brown ratio. I thought those perennial clippings would be considered brown carbon at first, but more research made me think it might actually represent green nitrogen. Those stalks weren’t breaking down much at all, so midway through the winter, I went at them with a pair of pruners to help speed things along. 

Through the winter, I added a whole lot of table scraps. I tossed in a bit of dried leaves and newspaper when I could, but that’s a challenge when there’s snow on the ground and you don’t get the newspaper anymore. Of course, eventually the whole thing froze.

Compost That Doesn’t Break Down

Our first truly springlike day was April 9. When I checked inside the tumbler, it was actually starting to look like compost. As the temperatures heated up, we started turning the tumbler again, but the compost just wasn’t breaking down much more. 

By mid-July, there were still big clumps in my composter and seeds were sprouting in there. I bought Espoma’s compost starter and added it in. For the first time, it was also looking dry, so I added some water. So nine months later, I’m still on my first batch of compost. 

I have a lot of beds to build and soil to amend, so I’d be happy to be making a lot more compost than this. Honestly, I’d be happy to just finish this first batch so I can get it out of my composter, start over and do a better job. 

So here’s what I think could have gone wrong: 

  • Not enough brown carbon
  • Not enough microbes
  • Too dry
  • Too wet
  • Not mixed well enough

Thoughts? What should I do with this clump of half-cooked humus? And how can I do it better and quicker next time? 

2 thoughts on “My Compost Isn’t Breaking Down: What Do I Do?

  1. Rainey

    I have absolutely NO bona fides when it comes to gardening — I’ve made every mistake in the book and many of them repeatedly and obsessively. But I’ve been composting for nearly 20 years and I’ll tell you what works for me in composting. A BIGGER pile. And far more than the 90 days some articles on composting taut.

    I started with a cute little 3’x3’x3′ composting kit and, tho things broke down they never got good and black. Over the years I experimented with different things. Now I have big 4’x6’x4′ high piles that are completely passive. And I don’t spend any time worrying about ratios or moisture content. Whatever I’ve got goes in a pile. When it rains my piles get wet — which is not often in my dry SoCal climate. I only turn them when they’re 80-90% done and loose enough to be turned. And I only do that if I feel like it. I have 4 big piles so most of the stuff has been in it’s respective pile for a year or 2. By the time I break one down it’s half it’s original size. There may still be branches or bones or shells or pinecones or other things that take a long time to break down that have to get sorted out and thrown back on a working pile. But what is composted is lovely earthy stuff. Big piles also generate the REAL heat that’s necessary to destroy weed seeds.

    My native soil is adobe clay. I mean the actual adobe that people once used as a building material! My lawn still struggles through that. But my compost has turned all my border planting beds into sweet arable gardening soil.

    My advice if you want the rich humus that composting promises is to make a much larger pile than a little tumbling composter provides for and be MUCH more patient.

    By the way, the small walnut size bits of branch and bark that I sift out of the compost I top dress with makes excellent mulch and will continue breaking down and enriching your soil while it helps retain soil moisture and represses weeds.

    1. Sara Tambascio Post author

      Thank you so much for this great info. Do you have any problems with animals? I think our summer garden project is going to be a bigger composting area. We just need to figure out where to put it.


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