Thursday, May 28, 2009

Compost Gnats and Escaped Worms

Last week I wrote candidly about the somewhat embarrassing fungus gnat invasion in my worm bin. As you may recall, my husband Steve and I moved the infested bin outdoors as a temporary solution until I could figure out what my next step was going to be, whether waging biological warfare (by adding beneficial nematodes to my bin to kill the gnat larvae) or something else.

I opted for "something else," because "something else" is free, and much less scary than playing with creepy living organisms that may or may not solve my problem. So the other day I got out a few five gallon buckets and my wheelbarrow (and yes, it's "wheelbarrow" and not "wheelbarrel", as I learned today to my chagrin). I lined these vessels up on a concrete slab in my backyard, opened the compost bin, and started sorting the contents of the bin. This tedious, messy and somewhat back-breaking process involved adding about two shovelfuls at a time to a wooden sifter Steve crafted for me out of wood and 1/8" hardware cloth, then shaking the sifter over the wheelbarrow to separate the finished compost and worm castings from the unfinished compost. While some of the worms did fall through the holes in the screening, it wasn't terribly difficult to pick them out. I put the unfinished compost in one of the five gallon buckets, and then a second when the first filled up.

Truthfully, this is the first time I have harvested my compost in the entire year of its existence and I realized while doing so the task was long overdue. While I have harvested small scoops of compost/castings here and there to make compost tea, I have never gone through the bin and removed vast amounts of compost. This experience taught me three things:

  • To avoid problems like fungus gnat and fruit fly infestations, bins should be processed more often than annually -- maybe once a season would make more sense for an active bin, as it takes about three months for worms to process food waste.

  • Just as it is very useful to have a two-sided compost bin in my backyard, it will also be useful to have two side-by-side vermicompost bins instead of one. So from now on I think I'm going to alternate between two bins to keep both of them active and prevent them from becoming overloaded and prone to pests. Also, under the right conditions, worms breed like crazy, so after one year I have more than enough worms to move them into new bins and share with others.

  • Vermicompost is amazing! The stuff I sifted was gorgeous -- well, gorgeous to an organic gardener, anyway. It's rich, dark and crumbly. I wish I had done this worm-bin-sifting earlier, because the compost I harvested will be extremely useful in my gardens. Although some of the things I've seen over the last few days aren't really for the faint of heart, it still seems worth it in the end when I think of all that rich stuff I'll be able to feed my vegetables.

  • I sifted through about 2/3 of my very full bin and obtained one five-gallon bucket full of finished vermicompost when I discovered that the compost in the bottom of the bin was too wet to sift easily -- it was smelly, compacted and borderline anaerobic. So I aerated the remaining compost by scraping it off the the screening and pebbles that cover the bottom of the bin. Then I covered it with some of the unfinished compost and worms and added lots of *dry* shredded newspaper to the bin. I tend to not moisten the newspaper if the bin contents are already too moist, which is a common problem with plastic containers. I am hoping the dry newspaper will absorb the excess moisture.

    Finally, I moved my processed bin to the basement, where I am going to let it sit for a while. In the meantime, I took the remaining unfinished compost and more worms and added it all to a brand-new bin. I covered the compost with shredded newspaper and set the new bin beside the original bin.

    Regarding the gnats, I haven't seen any since I went through this process, although I did notice that the two flats of spinach I've been growing on my kitchen counter were also infested with fungus gnats. I experimented with pouring a homemade cleaning solution of water, vinegar and peppermint castile soap on the soil, as I've heard that diluted castile soap can kill plant bugs. I should have just made a new solution, but I already had this old solution in a spray bottle, so I thought I'd experiment with it rather than make a new solution without vinegar. The solution I poured on one of the flats did seem to kill (quiet?) the gnats, but also proved to hurt the spinach plants, as this morning they looked kind of withered. Not sure what got to them -- the vinegar or the soap, or both. I am probably going to dump that flat in the compost bin out back. I put the other flat outside, where I'll probably leave it now that it's warm enough. That's where a majority of my growing is taking place anyway, so I might as well focus on the outdoors and save indoor gardening for the fall.

    One more candid confession: I have observed that two nights in a row some of the worms I placed temporarily in a five-gallon bucket with the lid loose for ventilation escaped. The awful task of scraping half-dried worms from my concrete basement floor is almost worse than finding a bin infested with gnats. Apparently these little red wigglers are SERIOUS night creepers and, in the dark, they will crawl to the top of the bin and all over the inside if it's shut. If a lid is open, they will crawl out of the bin and as far as they can get before drying up. If you have a worm bin in a place that is very dark at night, keep it shut, or make sure any screening you keep on top is too tight for the worms to crawl through (the 1/8" holes in the screen I put over the bin the second night apparently made for an easy worm exodus). After scraping about 20 dead worms from the floor, I think I've learned my lesson. Thank God they didn't escape onto carpet! Blech.

    So now that I've said all that, anyone still want me to make them a worm composter? ;)


    1. I don't suppose that it is possible to put a very shallow tray or small tarp on the floor underneath your vermicompost containers, sprinkle them with water (they're already in low ground places) so that you could possibly "trap" those escapees?

    2. Interesting idea, bluestem. Sounds like it's worth trying, except that my solution will probably be to get these extra worms into proper bins a.s.a.p. so I can get them out of the five gallon bucket, which I don't have a proper way to aerate at the moment other than by leaving the lid off. In my closed plastic tote bins the worms just crawl under the lid when it's shut -- they have never escaped, to my knowledge.