How Not to Vermicompost

In July-September in the carolinas, black soldier flies lay their eggs which hatch into larvae the can eat rotting vegetables many times faster than worms, probably on account of them having teeth. In fact, their chewing is quite audible. When they are ready to pupate (turn into adults), they crawl out looking for soil to bury themselves in. Being 40% protein and 30% fat, they make great food for chickens or fish, and harvesting them for biofuel shows some promise. For all these reasons they are welcome guests in the compost pile or vermicomposting bin.

Seeing the remarkable drop in bulk in my vermicomposting bin when the first wave of flies passed through, I decided it was time to harvest. I stopped feeding them for about 6 weeks, but when I tried to harvest it wasn't quite ready yet - too wet and the clumps turned very hard as they dried out. In the mean time, we accumulated extra compostables because it is prime harvest season in the garden. I just threw the empty bean shells and kitchen waste into a new bin and forgot about them for a month, hoping that the soldier flies would do their thing and pre-digest them for the worms. On that score I was not disappointed.

Caution: gross-out factor: high

But the added moisture has to go somewhere, and it had oozed out onto our patio in a small black puddle. From this, the mature larvae had crawled out looking for a place to pupate and painted a maze of wiggly little black lines extending several feet from the puddle. A little gross, but not a real problem.

I cut into a 29 pound watermelon the other day, found it vinegary, and added it to the compost. A nearby shovel chopped it up easily and I felt rather self-congratulatory as I showered the watermelon splatter off. Well, maybe 3 or 4 days later I opened the bin (which has no worms in it yet) and only the rind was left. The rest was positively crawling with tiny larvae, mostly looking like soldier flies. The pool underneath the bin had grown and now smelled faintly of immitation popcorn butter. Pretty gross, definitely a problem, but not pressing enough to get my attention.

A few days later, I went down to empty the kitchen compost bin (a 2-gallon bucket) and found a pool of black liquid several feet across with a white frothy center and a very strong smell of fake buttery trash. Around it for a couple of feet on all sides were the little wiggly trails of the larvae as they crawled away to pupate and were probably eaten by wandering birds or frogs. After a careful approach, I lifted the lid, the inside of which was covered in white fungus and now home to at least 3 fairly full-grown house spiders. If anything the larvae had multiplied since I last checked on them. It was time. The not-so-vermicomposting bin needed a new home away from our home.

Picking up anything over 100 lbs requires the yard cart, which of couse had a flat tire. Some wasp had discovered that the coupling on the end of the hose has the perfect size hole for raising a family. I had to disassemble the whole thing, pick the mud and a few wasp larve out with a bit of wire, then blast it with the garden hose, soaking myself in the process. Hose reassembled, tire inflated, I put the yard cart under the "worm" bin like a dolly and carted it out to its new home on some very poor soil under a tree in the yard.

Even hosing down the patio and sweeping it did not remove the black stains.