From Hope David, teacher at Ma’ema’e Elementary School

Uggy! What are these??!  They are swarming everywhere all over the bin, like an infestation!  Are they harmful to the worms?

No worries! These are compost mites.  Little moving dots, right?  In a variety of colors ranging from white, yellow, orange, and red, shiny and sparkling like tiny jewels in the sun?  Compost mites are eight-legged arthropods – arachnids – related to spiders.  These tiny guys and their relatives in the Order Oribatida occupy a wide variety of ecological niches as decomposers.  Mites are important partners in our worm bin ecosystem.

Compost mites are usually the first wave of organisms we see on feeding on fruit, bread, and other delectable worm food.  They have shredding mouthparts that shred cell walls so bacteria can get in and start to break molecular bonds. 

Poor mites have a lousy reputation. YES, some varieties are seriously destructive parasites and predators. There are estimated to be close to a million distinct species of mites, so that’s to be expected in such a big group.  We’ve all heard about the Varroa mites that have been decimating honey bee colonies, feather mites, fur mites, dust mites, the human-itch mites that cause scabies and spread diseases, and mites that cause galls in plants.   Most information you will find if you Google “mites” will be ways to get rid of them, even in worm bins!  It’s sad commentary on humanity that so many people lump together as villains all creatures they don’t understand. Your mites are just fine, lovely little helpful compost critters. Don’t do a thing.

There are legions of them in all mature, healthy bins, so don’t say, Uggy! Instead say, “Welcome, O Mighty Mites!  We appreciate your contribution!”

Your contribution is appreciated as well!  Post your comment, question, and experience below.

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Betsy Dyer
1 year ago

Our healthy home bins have all kinds of helpful critters that move the decomposing process along. The worms are flashy headliners for an amazing show! Thanks, Mindy, for your expertise! Looking forward to another article soon.

Phoebe Jefcoats
11 months ago

Thanks for this! It’s good to know that the mites I’m seeing in my bin aren’t cause for concern.