Fly poop --> compost?

May 23, 2010 10:52 AM

Compost question: can I turn this gloopy wet black soldier fly manure into usable compost?

My composting has been extremely low effort -- basically throwing kitchen scraps into the tumbler with no regard for ratios of green and brown. As a result it's way on the wet side, and has attracted tons of black soldier flies. I have no problem with them, and my dog likes to snack on the larvae. But the tumbler is now a wet, dark glop of what I'm guessing is soldier fly manure. It certainly doesn't look like compost. Is there any way I can turn the corner and salvage it? Possibly by throwing in tons of browns, or maybe adding compost worms (I've heard they like soldier fly waste)? Or can I just use the manure as fertilizer?

posted by malhouse to Home & Garden (6 answers total)

Does it smell more or less like compost? (Sweet, not rotten?)

If it smells bad, throw it out. If it smells okay, go with it. I'd probably throw some leaves or grass clippings in there to make it more like compost, and less like fly-poo, though.

Also, do you drink coffee? When I started putting used coffee grounds and filters in my bin, my compost improved a lot. I'm a lazy composter, too, and just throw whatever I have in there and let it go.
posted by zinfandel at 11:01 AM on May 23, 2010

If the compost has "gone bad" you will probably kill any worms you deploy. If you have access to sawdust or a bunch of shredded paper, try adding that for aeration and rotate the tumbler well. Mixing more "greens" into the "browns" should balance out some things, and the resulting temperature increase will kill off your flies. You want actively composting material to get hot, between 135° -160°F.
posted by wowbobwow at 11:31 AM on May 23, 2010

If it's "gone bad" it has bacteria that are more smelly, maybe anaerobic. Mix in dry stuff, likenewspaper or straw, and let it get drier, and it'll make fine compost, esp. for general lawn improvement. I never fussed over my compost, and it did a great job improving the soil at my old house. Can you leave the composter in a sunny spot w/ the door open, to dry a bit?
posted by theora55 at 11:52 AM on May 23, 2010

Response by poster: Thanks for all the suggestions. FYI, it smells like manure. Specifically, the manure of thousands of tiny larvae that feed on vegetable scraps. I wouldn't say it smells rotten though.
posted by malhouse at 12:29 PM on May 23, 2010

I had a tumbler for a while, and despite being diligent about adding plenty of browns on a regular basis and several times emptying out the thing, rinsing it and starting over, I never seemed to be able to do anything but create a massive soldier fly larva habitat. My theory was that the tumbler itself meant they could not crawl away and thus go unnoticed as they might in a pile, and that the small volume of the tumbler was never able to get warm enough to really "cook" effectively. I certainly never saw the steaming you're apparently supposed to. (This was, admittedly, my first attempt at compost, and having only a small patio and living in a place where it was too hot for a worm bin half the year meant I was limited to the tumbler.)
posted by jocelmeow at 2:28 PM on May 23, 2010

I think it's probably okay. Some people compost exclusively with black soldier flies.
posted by oneirodynia at 7:07 PM on May 23, 2010