Reader Questions – 06-29-08

These questions come from Alan, who is wondering about maggots and moisture in his worm bin.

Hey, I just had a question about some maggots I just
recently saw in my worm bin. I just started my bin early this month,
so I’m fairly new at this.

So, I’ve recently noticed maggots in my worm bin, and just before, I
noticed several of them squirming around in some uncomposted food. I’m
not really sure where they came from, since they’re actually fairly
large in size…about an inch in length. I read some other maggot
related instances on this site, but these maggots are much larger than
vinegar fly maggots. I’ve only left my bin open and exposed twice
(indoors) to let some of the moisture evaporate from the bin, so my
guess is they got in then. Also, my bin is in my dirt-floored basement
(on a table), so there seems to be a lot of chances for insects to get
in, but all the air holes have screen over them.

Honestly, the maggots are pretty gross looking and give me the creeps
since they’re so big, and I just was wondering what they could be, and
whether I should remove them.

Another quick question…there seems to be quite a bit of
condensation on the sides and lid of my bin. Sometimes a few water
droplets fall of the lid as I take it off. I’m pretty sure this means
my bin is too wet, but how should I get rid of the moisture?


Hi Alan,
Given the size of your maggots, and the fact that they are interested in your worm bin, I would guess that they might be some sort of Soldier Fly Larvae, which are actually excellent composters (like the worms) as well. In fact, some people raise them on purpose (often using animal manure as food stock) and sell them as live food for reptiles, birds and fish.

It’s a bit puzzling that they’ve been able to invade an indoor bin though – must have found a way to get into you basement somehow.

Anyway – while they won’t likely cause your worms harm, they are directly competing with them for food, and are grossing you out (haha) – so no point keeping them around. Simply remove them (perhaps a pair of dish gloves will help) and toss them outside or give them to someone interested in using them as food for other animals.

As for moisture levels in the bin, I definitely wouldn’t worry about condensation and dripping off the lid (I have a large indoor bin that always drips water from the lid when it is opened) – this is not necessarily an indication of too much moisture. I’d definitely be far more interested in the amount of water pooling in the bottom of the bin, if anything.

Hope this helps!


[tags]soldier flies, bsf larvae, maggots, compost, worm bin, worm composting, vermicomposting[/tags]

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

Making Vermicompost Tea

Next Post

Help Your Worms Beat The Heat


    • Kay
    • June 30, 2008

    Hi Alan & B.
    Just want to add my 2 cents …
    condensation can occur when the bin is hot (food composting, temperature increase) coupled with the bin being closed.
    best to pre-compost / partial compost the food.

    maggots, separate from the bin, add some food and keep in airy but closed container.
    see what it turns out to become … 🙂
    sounds like a science experiment …

    anyway, dirt floor basement … hhhmmm things that go crawling in the night (not referring to the worms)

  1. hmmm, I was just wondering about the condensation issue with my own (first) bin.. The temp doesn’t increase all that much in the house during the day, but I definatly see a difference in the amount of beading water at the end of the day vs. first thing in the morning.
    I’m going to try moving it somewhere else in the house to see if that happens… but I’m glad to know that I’m not the only one who’s got some water on the lid!
    thanks for such a great site!

    • Jennifer S
    • August 13, 2008

    I noticed recently that I have had an explosion of Black Soldier Flies in my bins. I am 100% certain that these new ones came in along with my latest batch of worms. I think some worm farmers are just more careful about what they send to their customers. I’ve always had a few flies – usually typical housefly size. These new ones are like passenger jets – each at least 1/2 inch long.

    Right now my only control has been to vacuum them up twice each day, but I’m going to have to get a little more aggressive. They need to be relocated to the compost heap outside. I don’t like it when the larvae wiggle all over the house. Ick.

    • Bentley
    • August 14, 2008

    Hi Jennifer,
    Thanks for sharing that.
    Unfortunately I suspect that it would be very difficult for worm farmers who keep outdoor worm beds to control soldier fly populations – although perhaps some sort of fine mesh bed cover would do the trick?

    I know all about the value of using the vacuum – but for me it is fruit flies and fungus gnats that are the victims!

    • Devin
    • June 30, 2009

    I have a big problem with extreme soldier fly population explosions in the summer (We have 30+ days a year over 100 in Fresno) so the heat is a major catalyst. Scooping them out with a garden shovel seems to be fruitless and I spend more time trying to get rid of them than anything else pertaining to my bin. I wouldn’t mind, but it has caused a fly population that is starting to annoy my neighbors. Any ideas for homemade soldier fly larvae traps? Thanks everyone!

Leave a Reply

Your email address will not be published.

Get Your Free Vermicomposting Guide!

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