I have been trying to absorb everything I can about vermicomposting over the last few weeks and even created my own bin design to make for friends and possibly sell as a part of my business idea, "Gardens, Not Garbage." Things had been going well all spring with my one-year-old vermicomposter and I was feeling pretty confident about my composting abilities until I hit a bump in the road the other day.
The problem is flies. Last year, a month or so after I first started my bin, I found I had what I thought was a fruit fly infestation. So I moved my bin from the kitchen to a shady spot in my backyard, stopped filling it with kitchen scraps for a few weeks, stuffed the bin with dead leaves and let it rest outdoors, where I kept it there all summer and for most of the winter. I thought, foolishly, that my worms could survive the cold if they were buried inside my big bin and the bin were covered with snow, which it was for most of the winter. However, in the late winter I realized I had frozen my worms to death. Ooops! Not ready to give up, however, I bought new worms from Growing Power, brought my bin inside and I was back in business. That was probably in March or so.
Anyway, it wasn't until this last week in mid-May that I discovered a halo of flies around my bin. I assumed they were fruit flies, so I did some reading online and tried one trick I found at Chow Tips: I filled a few containers with a mixture of apple cider vinegar, warm water, and a squirt or two of dish soap. I put a mason jar and a large bowl full of the stuff on top of my bin the other night and the next morning both containers had a great number of dead flies floating in the liquid.
Unfortunately, the bin was still surrounded by a halo of flies, and yesterday they were so bad, my husband pointed out, that if you looked closely at the window next to the bin there were tiny flies all over it. Nasty.
I did more reading and figured out that these aren't actually fruit flies. Fruit flies may be a problem, too, and maybe that trick with the vinegar did work for them. But it actually seemed to do nothing for the fungus gnats that may be the real culprit in this situation.
Apparently flies are a common problem among us "worm workers" (borrowing a phrase from Mary Appelhof, whose book "Worms Eat My Garbage" I am reading right now). I came across this blog in which the blogger explains an identical situation. He ended up purchasing nematodes online to put inside his bins, which he said seemed to abate the fungus gnat population.
I think many of my houseplants are also infested with the same kind of gnat, because for a while now whenever I water my plants I'll see tiny critters fly up and then go back down to the soil. I am not sure if these are a danger to the plant, or to my compost, but they sure are creepy!
I have always been very careful to bury the food scraps I place in my worm bin under copious amounts of shredded newspaper when I add waste every week or so. However, my husband and one of my children had recently taken to adding some kitchen scraps unbeknownst to me until I discovered a banana peel sitting right on top of the bedding. I read in Worms Eat My Garbage that fruit flies like to lay their eggs on their food sources (moldy fruit) so their offspring have something to eat when they hatch, but that fruit flies are not burrowers, so unless food is exposed in the bin they are not likely to go for it. Also, their eggs are often on the fruit we buy from the store, so it would make sense that a misplaced banana peel could cause an infestation.
The fungus flies are more of a mystery to me, and from what I have read, they are harder to manage. I'm not sure what has caused this fungus gnat infestation. It could be that they somehow found their way into my houseplants and then into my worm bin, or vice versa. I'm not sure if the banana peels are what caused this problem, or if it's something else, but either way I'm eager to find a solution. I'd hate for a few hundred highly irritating but mostly harmless gnats to spoil my vermicomposting operation. For now, at my husband's insistence, I have moved the bin outside until I can figure out how to remedy this problem.
To be continued...