Maggots ate my brain, er, compost
September 17, 2010 4:45 PM   Subscribe

Hello, Backyard Gardeners! So, I went to check on my compost bin and discovered a maggot invasion (warning: kind of gross) and I'd like to know if you have any advice.

A few weeks ago there was about 4 times the level of compostable material. Now the larvae have reduced it to what is basically a puddle of poop, with the corresponding smell. I don't particularly want a thousand beetles or flies or whatever they are to hatch there near my house, nor do I want more laying eggs in my nice rolling compost bin.

So, questions:
-Is there something organic that will both kill these things and allow what's left of the compost to be mixed with fresh material?
-Is maggot poop good for soil (like worm casings) or is this stuff kind of toxic to plants?
-What can I add that will kill them without using poisons?
-I'm not sure what originally attracted them, as I've had several batches of nice compost come out of that bin with no larvae. Should I avoid putting certain types of material in there?
-Should I just scoop out this stuff and hose down the bin and start over and not bother (this would be the last resort, as the aforementioned stench is not enjoyable)?

Thanks for any input!
posted by Burhanistan to Home & Garden (18 answers total) 6 users marked this as a favorite
Hmmm - I'm not really seeing what I would call "maggots" (which in my mind are fly larvae, and are white in color).
What it does look like is anaerobic decomposition - which is generally not a Good Thing for compost. I'd suggest adding a good carbon source (leaves, dried straw/grass - not green!) and aerating, then see how it goes.
There's nothing I know of to 'kill' this stuff.
Hope this helps.
posted by dbmcd at 4:55 PM on September 17, 2010 [1 favorite]

Well, they're not white maggots, but they are larvae about the size of maggots.
posted by Burhanistan at 4:56 PM on September 17, 2010

Fire is organic
posted by Napierzaza at 4:58 PM on September 17, 2010 [19 favorites]

I've heard of people adding lime (the mineral not the fruit) to the compost to help this sort of thing.
posted by The otter lady at 5:05 PM on September 17, 2010

Are you putting meat/dairy scraps in there? I don't know from personal experience (my partner and I don't eat meat, and dairy products rarely linger in the fridge long enough to be thrown out), but I understand that meat in the compost = (or at least can equal) insta-maggots. (Eggshells and clean bones should be fine, though)
posted by wreckingball at 5:39 PM on September 17, 2010

No non-vegetable material, as far as I know. They also made quick work of a huge bowl of potato peelings so I think they like veggies. Fire is indeed organic, but the compost bin would melt, alas.
posted by Burhanistan at 6:06 PM on September 17, 2010

It looks to me like your compost isn't getting hot enough. Is the bin in direct sunlight?

Also, boiling water will kill the maggots without toxic effects.
posted by kuujjuarapik at 6:38 PM on September 17, 2010 [1 favorite]

There are a lot of maggots in that bin. I don't know that any non-poisonous option would be able to kill all of them. I agree that your bin went anaerobic... it would be hard to coax that back into healthy compost.

If it were me, I'd start over. Dump the soup into a deep hole and bury it. That will take care of the smell and all the organic material will incorporate into the soil by next spring. There's nothing toxic there-- just gross.

Then, rinse out your bin: first with a hose to dislodge the junk and then with boiling water to kill unpleasant bacteria and any eggs that might still be clinging to it. Also, it looks like your bin doesn't have much drainage-- try putting in a couple of drainage holes and seeing if that helps the next time around. A sunny location for it can help a lot, too.
posted by oceanmorning at 7:39 PM on September 17, 2010

Yeah, start over. I kind of suspect that something non-vegetable found its way into there.
posted by Miko at 8:11 PM on September 17, 2010

Well, I'm disappointed that no one knows of any magic pixie dust that I can just sprinkle on that to instantly render it into rich humus ;). Looks like I'll be pouring boiling water on the poor bastards and disposing of the larval stew. Just FYI, it's an Envirocycle compost bin, and is well drained. I'd recommend it to others in spite of this current infestation. Maybe I'll post a video of the eradication tomorrow!
posted by Burhanistan at 9:15 PM on September 17, 2010

(also, it gets about 7 hours of Texas sunlight)
posted by Burhanistan at 9:16 PM on September 17, 2010

There's absolutely nothing wrong with maggots in the compost bin. Maggots aren't toxic, their poop isn't toxic, &c. They're just breaking down the material into more plant available nutrients. Compost dwelling soldier flies are the probable culprit, and they are actually a very beneficial composter. The adults die in 48 hours, they do not bite or carry disease. Studies on soldier flies show that they help inocculate compost with beneficial bacteria.

If you don't like dealing with them, they can be discouraged. What most likely happened is that your C:N ratio got out of whack, and/or you didn't have enough aeration. More carboniferous material, like dead leaves or extra shredded newspaper should be mixed in, and you can put an additional couple inches of browns on top to discourage females from laying eggs (they like high nitrogen material, like kitchen scraps).
posted by oneirodynia at 9:17 PM on September 17, 2010 [1 favorite]

Looks like I'll be pouring boiling water on the poor bastards and disposing of the larval stew.

Hmm, well, I hope you read my link before you do this. There's no good reason to, unless you just like killing things.
posted by oneirodynia at 9:19 PM on September 17, 2010

Too wet, too brown. Hot composting will kill the nasties.

I *do* compost animals, I *do* compost blood, and I *do* compost guts, there's nothing particularly hard about it. However, you've gotten out of balance. I'm not a huge fan of compost bins that don't rest on soil because I don't think soil microbes and goodies can make it to the compost.* What it looks like to me is that your compost is too wet and too full of carbon to reach a temperature that will kill the nasties. If that assumption is correct, more nitrogen would have started the pile heating up and prevented the infestation.

At this point, going off the appearance and without my trusty thermometer, I'd look to building a new pile with the current maggotfest in the middle of it. Ideally, this pile would be about a cubic yard/meter equally mixed between damp wood chips and fresh grass clippings with a nice hollow in the middle to pour the current nasty. This is probably not realistic.

An easy solution is buying a mess of pine shavings (or other wood that's not cedar, cedar doesn't rot) or dry wood chips and mix it in with the liquid and add some sort of nitrogen to get the pile cooking, maybe blood meal or chicken manure, and wet it down well. That should get the pile cooking hot enough to kill the maggots (150-160F, don't know C off the top of my head, sorry). This is a solution that assumes you're composting to dispose of materials you don't want to send to a landfill or, in an ideal world, a municipal composting facility. Or, you know, a hole in the ground.

If you're not an obsessive composter, I'd encourage you to pitch or bury the goo if you've got a good opportunity to do so. If you are obsessive, I've been reading this random blogger who seems to know their shit, anything on composting by Rodale, and the possibly mad Fletcher Sims.

On preview: Maggots in compost are not a problem in and of themselves. They are, however, an indication that the pile isn't hot enough to kill any pathogens or fungi that might persist in the parent material. The heat of a pile is not a function of the ambient temperature available to it, it's a function of the decomposition within the pile. Hay barns spontaneously combust if the moisture of the harvested grass isn't managed.

*That said, I made some compost in an above-ground tumbler and found earthworms in it. How did they get there? No clue.
posted by stet at 9:26 PM on September 17, 2010 [5 favorites]

> Compost dwelling soldier flies are the probable culprit, and they are actually a very beneficial composter.

Hmm. This may change things. The main problem I have with letting them live to hatch is that my backyard is only about 30 feet from patio to fence, and I just don't want a backyard full of wasp sized flies. I think instead of boiling them I'll try to strain them out and see if the birds want to have a go at them.

But yes, I need to try to get more dry roughage in there also. Thanks for the input.
posted by Burhanistan at 9:33 PM on September 17, 2010

Mmm, sloppy! Some great suggestions as to your next steps. My suggestion for the long term is to find some non-food stuff that you can dispose of in your compost bin, to keep it from getting out of balance again. Buying a big brick of pine shavings is fine, but who wants to buy stuff just to make compost?

I compost my paper coffee filters, along with newspaper (shredded) and even junk mail (that's on pulpy paper - none of the shiny stuff). If you have a cat, you can switch their litter box to Feline Pine and compost the scoopings. (Not the poop, just the clumpy bits.) Paper towels, notepaper, cereal boxes - there's a whole whack of stuff you're probably recycling that would do well in the compost bin.

Composting 100% food makes a mess. Basically you want to compost about 50% food and 50% "other." People get nutty about the specific ratios but personally I don't feel there's any need to over-complicate things.
posted by ErikaB at 9:36 PM on September 17, 2010

That should get the pile cooking hot enough to kill the maggots (150-160F, don't know C off the top of my head, sorry).

An aside: beneficial microorganisms are killed at these temperatures, which is not a good thing. In order to kill pathogens and weed seeds, compost should be kept at a minimum of 105 F for five days, with at least one 4 hour period of 113-150 F. (That's EPA regulations).
posted by oneirodynia at 9:55 PM on September 17, 2010

oneirodynia, I always look forward to be demonstrated wrong (I'm very pessimistic), but this is what my research has shown.

Well, the beneficial organisms that are powering the compost to the temp of 150F certainly aren't being killed. I'm going off of the data that the EPA states is current as of 9/16/2010 which states:
Using the within-vessel composting method, the solid waste is maintained at operating conditions of 55 °C or greater for three days. Using the static aerated pile composting method, the solid waste is maintained at operating conditions of 55 °C or greater for three days. Using the windrow composting method, the solid waste attains a temperature of 55 °C or greater for at least 15 days during the composting period. Also, during the high temperature period, there will be a minimum of five turnings of the windrow.
There is also a document produced by the Wisconsin State DNR (PDF) that is cited in my previous reference which states that:
(h) Materials resulting from composting shall be:
1. Stabilized to eliminate pathogenic organisms and to ensure that the materials do not reheat upon standing.
2. Free of sharp particles which could cause injury to persons handling the material.
3. Free of toxins which could cause detrimental impacts to public health or the environment.
Note: Pathogens are defined in ch. NR 204 as “disease causing organisms, including but not limited to certain bacteria, protozoa, viruses and viable helminth ova.”
Appropriate methods for pathogen elimination during composting are specified in 40 CFR, Part 257, Appendix II, Section B:
1. For in−vessel or static aerated pile composting, maintain a continuous minimum temperature of 55° C, or 131°F, for a minimum of 3 consecutive days.
2. For windrow composting, attain a minimum temperature of 55°C, or 131°F, on a minimum of 15 days, which are not required to be consecutive, and turn the windrow a minimum of 5 times during the high temperature periods.
While there is certainly bad shit that can't be composted away, hot composting destroys a good number of deleterious pesticides and microbes such as powdery mildew and late blight. My notion, which is informed by the flakey-looking-but-extremely-rigorous-and-well-informed Amigo Bob, is that composting eliminates most of the low temperature bacteria and provides a fertile ground for extant soil bacteria to colonize when applied to healthy soil.
posted by stet at 10:24 AM on September 20, 2010

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