I bought a composting bin with thermal-insulated walls, mainly for composting kitchen waste:


However, according to its thermometer, the temperature never rises over ~20 celsius. Youtube videos say that the carbon-nitrogen ratio should be 4:1, so I added some garden waste (both dry and wet leaves, and grass clippings) to the bin. Temperature still won't rise. I noticed some ants in the bin which I read, indicates that the pile is too dry, so I added a couple of litres of water. But the temperature won't rise, what is the problem? Any advice would be highly appreciated.

Picture of the contents of the bin:


This is an Aerobin composter and the purpose of that tube is to make sure that pile gets oxygen... who knows if it works. The weird thing here is that water seems to be steaming as I can see it on the walls, but that thermometer shows low temperature.

  • Any advise guys? Commented May 23, 2021 at 14:28
  • Sometimes it helps to inoculate new compost with some old compost, to add the microbes and bugs and such. Maybe find a friend with a good established pile and ask for a bucket of their compost. We've even once found that a bucket of really dry and spent-looking compost added to one of our bins really improved things. I guess it had some good stuff in there, despite appearances.
    – Emily Beth
    Commented May 23, 2021 at 16:09
  • @Emily Beth I have added some dirt in it for this very same reason but I guess I'll have to wait until the bin fills up. I also probably need to find some very carbogen-rich materials to balance the nitrogen of kitchen waste. Commented May 24, 2021 at 20:18
  • If you want results fast, add lots of coffee grounds. Commented May 26, 2021 at 9:35
  • @Polypipe Wrangler Thanks for the tip, gotta try that out. Commented May 26, 2021 at 14:52

2 Answers 2


Likely the volume of compostables is too small. It is really hard to get compost going in small quantities, and even the manufacturer of your bin suggests something like the roller bins for smaller amounts. You don't get the good heating, but there is mechanical disturbance and aeration. The solution really is to try to find a good supply of varied compostable materials, such as leaves, shredded newsprint, grass clippings, weeds, prunings and so on. Once the bin fills the heat should go right up.

  • So, ask neighbors and get a composting community project started.
    – Johannes_B
    Commented May 23, 2021 at 16:51
  • So the problem is that the pile is too small? Well, time will fix that :) After it eventually heats up, how long does it take before compost is ready? Commented May 23, 2021 at 17:15
  • Too small. When cutting heavy spring grass growth in IL , the large pile of clippings would first steam then make wisps of blue smoke. Commented May 23, 2021 at 21:09
  • @blacksmith37 The size of my bin is 200 litres but I haven't filled even half of that... hopefully it heats up after it's getting close to full. Commented May 24, 2021 at 14:43

Your C:N ratio is off.

It should be 25-30:1 ish.

  • Really? Is that measured in volume or weight? What are some very carbogen-rich materials? Commented May 26, 2021 at 17:19

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