Ants and Snails and Maggots in Your Worm Bin?

Here is an interesting email from Liz:

I’m new at this composting and have set up a 25 gal trash
bin with lid outside. Put several holes on the bottom and sides. Have
been adding kitchen scraps,newspaper and cardboard,coffee grounds,
etc… of course ~ 1000+ red wigglers and things looked good, then all
of the sudden I was getting ants, snails and now it appears that the
bin in infested with brown maggots and you can here them crawling
around. What have I done wrong? Have you heard of this problem? And
what do with what’s in the bin? Help!

Wow, Liz – sounds like quite the invertebrate party going on in your worm bin! 😉
It all comes down to the one key word I saw in your msg: “OUTSIDE”!

Outdoor systems are – not too surprisingly – far more prone to invasion from any number of different critters, and the good news is that there aren’t all that many you really need to worry about.

I’m not a huge fan of ants, but I have loads of them on my property, and in most of my various outdoor vermicomposting systems – especially in the worm composting trenches. Rather than going on a ant-killing rampage however, I’ve opted instead to mellow out about their presence, and put more focus on creating the ultimate habitat for the worms. Thankfully, the ‘ultimate’ worm habitat isn’t all that thrilling for ants.

Ants prefer fairly dry conditions, so if you are keeping your worm systems fairly moist at all times, the ants will be far less likely to set up shop (ie nest). They WILL still venture into (and out of) the bin/bed, grabbing some food to take back home, but in all honesty this isn’t really something to worry about. That being saif, I should mention that there are some really aggressive/annoying species of ants (such as fire ants) that may warrant a bit more attention/prevention.

If at all possible, you might think about propping your bin up on legs or a pedestal in a tub of water – basically requiring that the ants (and other non flyers) swim across your moat in order to reach the bin. You also might try adding shallow dishes of syrup/honey mixed with borax nearby to act as a diversion (and eco-friendly ant killer).

As for snails – I’ve never really had any in my systems, although from time to time I’ll see some slugs. Again, definitely nothing to worry about here – unless we are talking about some crazy sort of carnivorous, worm-eating snails (I think they may actually exist, believe it or not). Your typical run of the mill garden snails and slugs on the other hand will likely just stick to feeding on whatever scraps you are adding. The water moat should work fairly well to keep them out as well.

The ‘maggots’ are almost certainly some type of soldier fly larvae, and will not harm the worms either. They are in fact reported to be excellent composting organisms, and some experts say they work very well with Red Worms. If you want to discourage them and other bin critters in general, you MAY want to feed a little less, and add more bedding types of materials. Often, when lots of new critters appear in a worm bin it is the result of there being excess food – they are simply there to take advantage of an untapped food resource.

Bottom-line, Liz – what you’ve encountered is very normal, and the only thing you might be potentially doing ‘wrong’ is overfeeding (just a hunch on my part). Again, if you simply cut back on the feeding, and take some of the suggested actions mentioned above, I suspect that you will begin to see a reduction in the number of invaders in your bin.

Hope this helps!

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  1. I have 3 Rubbermaid Bentley Bins or RBBs for short. I lined the inside of my RBBs with some of that cloth window screen. No bugs, except for spider mites (and not that many).

    • Liz
    • August 5, 2009

    Thanks, thats a good idea – a little late at this point the bin is very heavy but, will keep in mind thanks!

    • Uncle Jim's Red Wiggler Farm
    • August 5, 2009

    Something that helps really well to keep the ants from entering the bins is to line the top rim or the container with vaseline. the ants won’t cross the vaselined barrier, leaving the bin ant free!

    • Bentley
    • August 5, 2009

    Some great additional ideas!

  2. I’ve also got some maggots in my bin outside. It doesn’t bother me too much right now, but I’m wondering what’s going to happen in the winter when I need to take the bin inside!

    • Bentley
    • August 5, 2009

    Hey Chris,
    To answer your question – there is a very good chance that whatever type of fly happens to be laying eggs in your bin will be long since finished with breeding etc by then, and all maggots will have matured and flown off. Especially if you leave the bin out there until it nears the freezing mark at night.

    • allochthon
    • August 5, 2009

    And I’ve been trying like crazy to attract soldier fly larvae to my bins!

    • Bentley
    • August 5, 2009

    Yeah – that’s the funny thing! A lot of people are horrified when soldier fly larvae appear in the worm bin, while a lot of OTHER people wish they could get some, but never do.
    If only these people knew each other!

    • Selene from Florida
    • August 6, 2009

    My bins are inside but I did the aging of the bins outside before I got my worms. I had the ants and soldier fly larvaes also. Once I was reassured that none of those were gonna kill my worms, I chilled. I got rid of the ants by putting a small container of honey in the bin and using boric acid outside the bin on the trail of the ants. It only took a few days and I haven’t had a problem since. And like Bentley said, the fly larvaes are beneficial. They DO get out of the bins though. I find them every day crawling across the floor and I’m seeing the adult flies every day too. I throw the larvaes outside in my compost bin and toss the flies out the door to continue procreating more of this amazing insect!!

    • Liz
    • August 9, 2009

    WOW what a hot topic – I had no idea that maggots were as common as I have read. Thanks for all your suggestions. I’m not so worried about my worms and the black gold!!

  3. Wow, I also thought soldier fly larvae were a problem! Glad to know there are actually folks out there trying to attract some. If only I had chickens who could eat them for feed..

    The cloth windows screen is a great idea too, thanks.

    • jimmy johnson
    • May 10, 2014

    I have tried the cinnamon thing and I will post how it turns out.

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