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!