I originally found out about the worm bin class I attended yesterday through one of my other gardening classes with the Pierce County Edible Garden Series. There’s still one more worm bin class this summer in June if you want to sign up! The class itself was free, but I opted for the $30 worm bin and pound of red worms to take home. Worm composting (aka vermicomposting) is supposed to be a great way to take care of non-dairy/non-meat food scraps and their poop is supposed to be a fantastic additive for a garden (and horrifically expensive if you buy it as a finished product, from what I’ve heard).
To make a worm bin, you’ll need a container (there are loads of options online, ranging from really cheap DIY to pretty spendy pre-made), strips of cardboard or newspaper, food scraps (the moldier the better!), and red worms! Earthworms/nightcrawlers won’t work for this… they have a much slower metabolism than red worms, and a somewhat different diet.
When I left my class, I had a 14 gallon Rubbermaid Roughneck Tote with many holes drilled in the bottom, as well as around the top 1.5 inches of the tote for air flow, a heap of cardboard strips, and a pound of worms (in dirt/worm poo) in a gallon ziplock, and some info and how-to sheets:
It was also recommended during class that for the first batch of food, it may work better to run it through a blender or food processor (my blender may never be the same again!). This is because the worms are typically “fed” a layer of manure at the worm farm, which requires less work on their part to consume than food scraps, and may help keep them from trying to leave your worm bin to go find the tasty manure.
Last night, I set up my worm bin and left it on the plastic lid from another container, and kept a light on over the bin all night – this was also recommended because the worms hate light, and it would help keep worms from wanting to escape. This morning, there were a couple of worms between the bin and the tray underneath (which were promptly deposited back into the bin, under the top layer of bedding), so I’m glad they didn’t wiggle off somewhere in the garage!
Today, I picked up a second matching tote at Fred Meyer. I got an 18 gallon because the 14 was out of stock, but I like that there’s actually more space between the inner and outer totes this way for air flow. I drilled holes in the sides near the bottom of that tote as you can see above, and I may go back and add a few more holes for good measure. The 14 gallon nests inside the second tote, and the holes in the sides allow venting through the air holes in the bottom of the inner tote, as well as collecting any moisture (or worms) that seep out. Pierce County has a great video tutorial on YouTube for this type of worm bin, and also has directions you can download for making a wooden worm bin. A tip: if you have a small step drill bit, touching up your holes with a step drill bit is a great way to take care of the plastic boogers that get left on a lot of the holes by the regular drill bit, which gives it a cleaner look.
The class instructor (and, I believe, the video) recommended keeping your scraps in a small container (like a tupperware) in your kitchen during the week, and then adding them to your worm bin once the container was full. I’m hoping to find one of the cute kitchen composting containers to use, instead… loads of those have carbon filters in the lids to help with odor – and fruit flies that are attracted to odor.
Rather than Amazon or other online retailers, the class instructor recommended ordering red worms through Yelm Worms if you need to purchase worms, as they’ve got far more reliable shipping (worms arrive alive instead of dead) than some other options. Thankfully, unless something goes terribly wrong in your worm bin, it’s a one-time purchase as your worms will make new worms every few weeks! They also handed out a troubleshooting guide for problems that might arise, as well as an 18 page guide on all things worm bin, called the Worm Digest.
You can harvest your worm compost after 2-3 months, and there are so many ways to do so! There were two ideas that I really liked. One of them was brought up in the class I attended – make a second tote identical to the one that holds your worms, with the holes in the very bottom, remove the cardboard bedding from the tote containing the worms, and stack the empty tote directly on top of the worms/compost. Start putting food scraps in the top tote, with cardboard bedding on top, and the worms will migrate up through the holes in the bottom into the new tote. Your middle tote now just contains your worm compost, ready for use! The other method I liked is to scoot all of the finished compost – worms and all – into one side of the bin, and just start putting food in the other empty half. The worms will migrate to where the food is, and you can scoop out the finished compost. The instructor of the class said that when he harvests his compost, he doesn’t worry about picking out every single worm, but just aims to keep about 75% of his worms in his bin.