Worm Bin Update: Time to Harvest Some Castings

It’s been awhile since I posted anything about my ongoing experience with having a worm bin in the house, so I thought I’d offer an update for those who are interested in such things. If you’d rather do just about anything than read about worms, how about checking out Paige Johnson’s wonderful Garden History Girl blog. Paige has a master’s degree in garden history and her blog is well- researched and packed with great historical photos and illustrations. I’m looking forward to interviewing her soon for a future post.

Next time, I’ll harvest worm poo outside.

Okay, for those who are still with me, let’s talk worms. I started a worm bin back in late February. I went the less expensive route with one of those large plastic storage totes from Target. But after a few months, I opted to move all those little red wigglers into a new condo-style bin with trays. I was warned by more than one experienced vermicomposter that the tray systems can be a hassle, and they advised me to hang on to my big, cumbersome tote. I stowed it away in the garage, but I’m not going to go back to it.

I like my stackable Worm Factory 360 because I can see the worms much more easily when they’re eating the food scraps that I add to the top tray every other day. For instance, I now know that they really like banana peels, coffee grounds and orange pepper bits. But they aren’t as keen on kale, tomato chunks or onion skins. I wouldn’t know these things if I were still using the tote, which was so deep, it was hard to see the worms much at all. For me, being able to actually watch the worms in action as they eat, mate, lay eggs and just crawl around makes having a worm bin in my dining room worth it. (The basement’s too far away and there’s no room in the kitchen. I swear we have no issues with fruit flies or smells!)

Trying to find all the baby worms was no easy task.

Sure, I like the fact that all those worms turn our kitchen scraps into nutrient-rich castings (poo) that I can use in the garden. But without the opportunity to observe them in action, I might not be so interested. It takes worms in a system like the one I use several months to produce enough castings to feed a small section of garden. And I have to say, the process of harvesting castings is pretty gross.

I harvested castings for the first time last week. I waited longer than I should have, and I won’t make that mistake again. With stackable systems, the top tray is the “working” tray where you add food and the worms feast. The bottom trays are called “processing” trays where food and castings are in various stages of decomposition. Essentially, you start with one tray and once it gets about three-quarters full, you add a new tray, and so on. There is no exact time to harvest castings from the bottom tray. The instructions say to harvest when the “material is nearly black and the chunks of matter are small.” From what I’ve read, three to fourth months is generally a good amount of time to wait before harvest.

I waited six, and there’s no harm in waiting longer. In fact, the worms will keep working over the stuff in the tray the longer you leave it, which is what happened in my bottom tray. Apparently this results in even richer vermicompost. The downside being that the tray you have to deal with is filled with a sticky, mud-like mess, which might not have been a big deal were I not the sort of person who anthropomorphizes all creatures. That being the case, rather than just dumping the black goo onto a tarp outside to dry, I went through it with my hands trying to pick out big worms, all those tiny baby worms, and the zillions of eggs that hadn’t yet released even more newborn worms.

Anyone up for a nice bowl of red wigglers?

After that, I did as advised and dumped my harvest onto a tarp in the yard. And then I checked on it daily to sift out more worms that I missed the first time. The whole process took about a week and, because of a poorly placed sprinkler, the vermicompost was still wet when it came time to distribute it around the garden. Again, I won’t make that mistake again next time. After scooping some of the goo into a small container and distributing it between a few of my houseplants, I used the rest in a spot in the garden where plants aren’t doing too well.

Over the next few days I went around breaking up the chunks of goo (which sort of started to resemble pieces of volcanic matter)  into smaller pieces because I read that vermicompost can harden into a “cement-like” substance. I’m here to tell you that “cement-like” is an understatement. Whew! You want to knock somebody out, hurl a chunk of vermicompost at their head. Now, I guess it’s time to watch and see how the plants that got a taste of vermicompost react.