Site search



An Explosion of Worms . . . and Flies

We checked on the old worm bin—the one we haven’t been feeding—and were amazed to see that it’s full of worms. Huge ones, too! If you remember, we had separated the worms from this compost and started a new bin with them. We were quite thorough—more so than I think I would be in the future—so these worms must have come from the few cocoons or baby worms that slipped through. We haven’t even fed them for over two months; they’ve just been finishing the old compost. (Which is looking pretty good, by the way, but I think I’ll let it go for another month or so in order to make it usable for our houseplants.)


Not feeding that bin for a couple months has completely eradicated the fly population living in the compost. Unfortunately, it looks like they’ve all moved to the new bin.

This is so embarrassing! I swear I’ve never had a fly problem before. We’ve been keeping the flies out of the rest of the house by storing the fruit in the fridge and the dirty dishes in the dishwasher, and putting out cups of apple cider vinegar.

To get rid of them completely, we’re going to stop feeding the new bin for a few weeks. It takes fruit flies 10 days at the most to mature from larvae, and as we’ve seen with the old bin, the worms can survive (even thrive) far longer than that without new food.

We’re also going to add a fly trap to the bin. We’ll make one by putting an apple core in a jar, snipping off a corner of a Ziploc bag, and attaching it to the mouth of the jar with an elastic. If we kill as many adult flies as we can and withhold food so they don’t multiply, we could solve this problem.

To prevent it in the future, from now on we’re going to freeze all of our scraps before adding them to the compost. That’ll kill any eggs that might stow away on fruit peels. Wish us luck!


Comment from Dan Ruben
Time December 9, 2009 at 1:35 pm

I used to have a fruit fly problem, and don’t have one any more. Here’s how I solved it.

1. I don’t put banana peels in my indoor compost pile. I think that most of my fruit flies come from them. For good measure, I do the same for the skins of cantaloupe, grapefruit and oranges.

2. Sometimes I get a few fruit flies buzzing inside the can in which I store my compostable waste. When I notice this problem, I take the container outside and open the lid. The fruit flies fly away.

Pingback from Looking Back at 2009 « Pragmatic Environmentalism
Time January 4, 2010 at 9:08 pm

[…] one worm bin and moved the worms over to a new one after a couple months. But we’re having fly problems right now and aren’t feeding the worms again until the flies go […]

Pingback from Worm Update: No More Flies « Pragmatic Environmentalism
Time April 28, 2010 at 8:32 pm

[…] worms We checked on the worm bin tonight, and—finally!—the flies are gone. It’s taken four months of no feedings to eradicate the pests, but it eventually worked. (The spider that we found inside may have helped, […]

Pingback from Pragmatic Environmentalism
Time January 18, 2011 at 2:41 pm

[…] One year ago: An Explosion of Worms . . . and Flies […]

Write a comment