Overwintering Compost Worms, or Hawaii for Red Wigglers

I have worms living in my bathroom. Yup, you read that right. When the nights started turning cold this fall, I negotiated with Kelly for some worm space in the back bathroom. The back bathroom is also home to Pudy’s litter box, our bee suits, my hanging produce scale, and a rotating lineup of anything else that we at one point felt the need to shove out of sight quickly.

In our mild Bay Area climate, red wigglers can survive just fine outside for the winter. All they need is shelter from the rain (to make sure they don’t build up excess moisture), and a diminished supply of food. The thing is, even though they survive, the worms do slow down in the colder temperatures. So if you’d hoped to dump your Thanksgiving leftovers in the bin, you may be in for a rude surprise when the worms don’t chow fast enough and you end up with a rotting, stinking mess.

The other area where red worms slow down is reproduction. This was my main concern because, though I have other ways to compost my kitchen scraps through the winter, it’s important to me that the worms continue building their numbers. I’ve admitted before to being a cheapskate, and investing in worms is no exception.

When I decided to get my worm bin back up and running last spring, I begged a small population of worms off some friends and have been coaxing them along ever since.

I also discovered that there were considerable (if quite dispersed) populations of red worms that found their own way to my freestanding compost piles, as well as (somehow) into my compost tumbler.  When I’m feeling overzealous, I go out with a little pail and hunt for worms to relocate to the worm bin.

In preparation for the worm winter vacation, I spread a plastic garbage bag in the corner of the bathroom in case of any bin leakage. On top of this, I positioned a plastic crate to get the bin off the floor and seated the bin on top. I lined up a quart canning jar under the bin’s drainage hole to catch the slow drip of “worm tea.”

The setup.

Good news: Three months in, and the worms are doing fine. Their numbers seem to have increased, and the worm castings are building up. In fact, just last week I added the bin’s third tray.

There’s no noxious odor and no issue with fruit flies. A guest who recently used the back bathroom didn’t even realize she was sitting next to a bin of worms and decomposing produce. She decided the whole getup was a “gravel sifter.” Go figure.

The worm’s winter diet has thus far consisted largely of rotting apples and overripe persimmons. I’ve also added a fair bit of lettuce and other vegetable scraps. Ultimately, I’d like to be able to compost the majority of appropriate kitchen and table scraps in the worm bin, but at this point I’m still worried about overwhelming their population size with too much food.

The newest tray of food scraps and shredded paper.