Fruit Fly Freezing Wrap-Up

I’m sure some of you are interested to find out how my fruit fly freezing trials have been going. Well, the long and the short of it is that I am now quite convinced that freezing food waste (in my deep freezer anyway) does indeed kill off fruit flies, larvae and eggs.

My second trial involved filling a big ziplock bag with food waste that was clearly overrun with fruit flies (it had been sitting in a bag out on my deck for quite some time, and clouds of fruit flies would emerge any time I opened it up for a look) and then tossing it into my chest freezer. This time around, I removed the bag from the freezer within a day or so, opened it up, then put it into the cardboard box I used for my first trial (the idea being to allow the contents to “breathe”, while preventing any fruit flies from getting in).

When I checked on the box a couple of days later I was intrigued to see a small cloud of fruit flies circling it. I thought for sure that the material inside had become a breeding ground. When I opened up the box, however, there was not a fruit fly in sight. Clearly, the fruit flies in my house had been drawn to the box due to the tempting aroma, but had not been able to breach my defenses. Just to be safe, I popped the bag back into the freezer for another day before letting the bag sit out again. Recently, I went so far as to leave the bag open to see if I could get some of my own fruit flies to breed in the material, but haven’t even had any luck with that (seems the number of fruit flies in my house has dropped considerably). I will likely try leaving the bag outside for a few days for the sake of seeing how quickly fruit flies could colonize it if given the chance. But, all in all, I’d have to say I’m still thinking that freezing is a good way to get rid of them.

That being said, if anyone tries this out for themselves, please do let us know how you make out! If I wanted to be really thorough, I might try putting bags of infested waste in my refrigerator and in my smaller freezer (sitting above the fridge) just to see how the fruit flies fare in those situations. I’ll let everyone know if I decide to do so.

Previous Posts
Does Freezing Kill Fruit Flies?
Fruit Fly Freezing Update

**For Even More Worm Fun, Sign Up for the RWC E-mail List!**
Previous Post

Interview with Maria Rodriguez – Byoearth

Next Post

Wooden Stacking Bin-09-29-10


  1. I must not have had the fruit waste in the freezer long enough. I am happy I was able to generate a good study of the problem as I am not as studious as you are about the situation.

    I harvested my Worm Inn today and must bow to your experience. What a wonderful harvest of VC and the cocoons!! There were hundreds and big and juicy. The Can O Worms will be used because it was my first but I am a big fan of the worm inn because of your encouragement. The flow through technique is wonderful. There is a lot of coupling going on at the bottom of the Worm Inn much more than my COW.

    • Steve K
    • October 5, 2010

    While you have been freezing fruit flies, I have been freezing fungus gnat-filled food. It seems like I am getting the same end result (i.e., no more fungus gnats in my BOM-6000), which makes me think that freezing is the way to go. That said, I didn’t use the same level of scrutiny you did, I just took the week-old food from my crock, which generally has fungus gnats in and around it, bagged, and froze the contents before adding to the bin. I have also been feeding the bin less lately, so that may be a confounding factor. Regardless, the wife is much happier that the gnats are no longer hanging around the worm bin, though I think the local spider community is probably less enthusiastic about the drop off in gnat numbers.

    • Dave Story
    • October 17, 2010

    My bin was not ready when the worms arrived and I did only had a small amount of scraps ready, but I did use cardboard. Now the scraps are pleanty. I have noticed less worm acttivity on the sides and top of my bin. how do I know if most of the worms are alive?
    PS. I am going to freeze my scraps now.

    • Metqa
    • July 16, 2011

    Well, based on your freezer experiment and faced with the problem that my worm population is not growing but my fruit fly population is thriving, I’ve pulled out all of the adult worms I could find and froze the bin.
    Actually what I did was to pull out the worms and put them safely away, and wrap the shoebox size bin in pantyhose nylon for a couple of days to contain the flies and give any worm babies a chance to hatch and show themselves. After releasing a cloud of newly hatched flies, I re-fastened the nylon over the bin and put the entire bin in the freezer. since there is no lid except the nylon, I’m hoping the cooling air of the freezer will reach all parts of the bedding, which I fluffed before freezing.

    I hope in a couple of days I’ll be able to thaw the bin, fruit fly free, and put the worms back in to finish their work and hopefully multiply without bother of fruit flies.

    • Metqa
    • July 22, 2011

    Okay, Good News on this experiment. I left the bin in the freezer for about 3 days till it was frozen solid. then I let it thaw, with the pantyhose mesh in place for two days, till the bottom no longer felt cold. I wanted to give any bugaboos a chance to thaw and wake up. Then I peeked under the mesh, I saw NO activity. even after digging through the bedding, I saw no movement. So I decided to replace the worms. I’m glad I did it one by one, cause as I pulled two worms apart, I saw a fruit fly maggot squeezed between them. I’m sure it was fruit fly larva cause it was bright white, so I put only the worms back in. It’s been a couple of days and I still see no flies in the bin and the worms seem happy enough. and the bin smells less like ” acrid rotting” and more like “earthy mold”. I’m still working out plans for my MINI, so hopefully the worms will be happy and fly free in their shoebox bin. All of their food is chopped up and in the freezer hard frozen. I hope this helps keep future fruit fly populations out!

    • Metqa
    • September 28, 2011

    Well, things had been going so smoothly it was too easy. I’d been freezing my scraps and feeding the bin directly from the freezer. Sometimes, I’d chop it up with a fork, or I’d blend it before freezing, but regardless, I fed directly from the freezer, frozen solid scraps. and up until 2 weeks ago, I had NO flying insects in the bin at all. I’d seen some long crawling things, but they weren’t in large number and not infesting so I worried not.

    I made a HUGE mistake two weeks ago. I’d bought a melon from the farmers market, and kept it in the fridge till I ate it. I cut the rind off and thought ” my worms might like this sweet treat” and guess what I did wrong… I put it directly into the bin WITHOUT FREEZING IT FIRST.
    Two weeks later, my bin is full of gnats and maggots. two full months, 8 weeks of weekly feeding with No flies whatsoever and One stupid melon rind causes a gnat fly infestation in less than two weeks. I’m so angry with myself, but I’ve proven to myself that freezing is ESSENTIAL to keep a small apartment bin free from flying insect infestation. Now I’ve got to de-infest my shoe box bin all over again!

Leave a Reply

Your email address will not be published.

Get Your Free Vermicomposting Guide!

* Join the Red Worm Composting E-Mail List Today *