Cockroaches in the Compost
Question
March 9, 2023
Question from a Sandoval County Master Gardener: A Placitas woman (87043) has written to our Helpline asking why cockroaches keep infesting her compost tumbler. I've asked her for more information about how she composts, but while we wait for an answer, do you have ideas?
I use elevated tumblers without that problem, but I also keep a slash pile outside our walls that contains grass clippings, rocks and fill dirt. Last time I dug out some dirt, I uncovered a tidy little nest of cockroaches. Maybe your answer will also help me understand that.
Answer(s)
Answer by RR: As a master gardener, you likely understand that composting is human involvement in the natural decomposition of organic materials. This decomposition is accomplished by a whole ecosystem of living organisms, one of which can be the cockroach. Unfortunately, by adding too many nitrogen-based materials, such as decaying meat, grease, and dairy, to the compost, it will start to smell. This could easily activate a cockroach problem. These resilient creatures live in compost because it’s an abundant food and moisture source. They chew on organic matter, helping to break it down, and their feces adds nutrients to the compost. However, knowing they are beneficial in the decomposition process does little to diminish the “yuck factor” when most folks encounter cockroaches. If accepting their presence is not an option, cockroaches can be removed with diatomaceous earth, although this will likely have the unfortunate effect of killing other beneficial bugs. Heating up the compost with appropriate C:N ratio organics and moisture content will make a compost pile uninviting for cockroaches and many other creatures. Ensuring the compost bin is sealed, except for the air holes, which should be screened, will help keep them out. Man will never be able to get rid of the cockroach, so what better place to have them than where they are performing a beneficial use, the compost pile. After all, if they are in the compost, the less chance of them being in the home.
Other options for those who want to compost but are turned off by cockroaches can be Bokashi, and secondly, composting with worms, or vermicomposting. Information on these can be found on our website at https://www.nmcomposters.org/handouts.
I hope this helps your concerned citizen. Happy Composting!