Fruit Flies in Worm Bins: How to Prevent Them

Fruit flies can be very annoying to get rid of. What can you do to prevent them from infesting your worm bins?

Soon after I began vermicomposting (composting with worms), I noticed hundreds of fruit flies swarming around my compost bins. These flies were not only annoying but also disgusting.

Let’s look at some strategies I’ve learned for combatting fruit flies in compost bins.

Add a Top Layer of Plastic or a Sheet of Newspaper

Place a piece of plastic or a sheet of newspaper on top of the worm bin contents. This newspaper or plastic cover will protect against flies entering the bin. While this method does not prevent all flies, it can be pretty effective even on its own.

Put Shredded Newspaper or Leaves Over Table Scraps

Bury food scraps entirely in newspaper shavings, leaves, or other bedding when adding them to the worm bin. The more layers of paper shavings or leaves you can use, the better.

This layer makes it more difficult for flies to get to the food scraps and allows for good aeration. Aeration is essential for the health of your worms as well as the prevention of problems associated with anaerobic composting. Worms also enjoy eating and digesting newspaper and leaves.

Add Nematodes to Your Bin

Nematodes are microscopic organisms that kill pests while leaving beneficial organisms alone. Adding nematodes will not eliminate a fruit fly colony but will help fight off any eggs in the bin.

When collecting your finished product, take a scoop of finished vermicompost and return it to the bin. This scoop will contain some of the nematodes, which will aid in the fight against flies in your next batch.

microscopic view of nematodes

Use a Row Cover Cloth

A row cover cloth placed over your bin will help maintain proper aeration while also preventing fruit flies from entering your bin in the first place. Secure the row cover cloth around your bin with a large rubber band, rope, or bungee cord.

Alaine Connolly
Alaine has been working way too hard in horticulture since 1992, beautifying golf courses, resorts, and hotels. She is a part time landscape designer who works full time caring for a 28,000 square foot public garden. At home, she maintains her own 400 square feet plot. Alaine lives in northern Illinois - zone 5b.
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