The Vermicomposting Bin

Before you choose a bin, please be sure you're familiar with the first fundamentals article: everything about a successful worm bin is predicated on meeting the worms' and microbes' needs as described there. The main thing to know is that surface area is more important than depth or total volume: worms will largely live and work in the top six inches and they need to breathe, so deep bins with less surface area aren't very suitable. A 5 gallon bucket can work but is about the limit of depth for little surface area; this is why we either use wide and shallow bins or use fabric flow-throughs for worm bins.

DIY bins

The most common, easy, all-purpose nuclear bedtime story worm bin is the classic Rubbermaid-style plastic storage tote (with some modifications). They're great starter bins because of their low cost, easy availability, and they work well as long as you pay attention to fundamentals (which is true for any bin). Plastic totes offer good protection from light, contain the moisture of the bin, have a lid, and can be shifted and moved easily. They can however retain too much moisture and can be limiting for airflow, so it's important to modify the tub with air and drainage holes and monitor it closely especially on the bottom and in the corners.

My most successful tote bins are when I use TWO totes that stack together. The outer (and lower) tote is left intact, except perhaps one one-inch hole an inch up from the bottom. It functions as a drip tray of sorts so if you overwater it will catch the leachate (this should be a very infrequent problem if you monitor bin moisture adequately, leachate is a sign of too much moisture). The hole allows air to circulate around the inside tote, and observing the floor of the outer "catch" tote to see if leachate is accumulating down there. It also lets air in so when you lift out the main upper bin there isn't a vacuum working against you. By drilling drainage holes in the bottom, lid and sides of the upper tote, it can drain freely if there's too much moisture and allows air to flow by the bottom of the bedding.

Because I'm a bit of a stickler about air flow, I even set the top tote on a couple bricks or the like to offset it even more from the outer bin giving air space on the bottom and sides. I find that the more air circulating outside, the fewer crawlers (escapees) try to leave.

Check out Bentley "Compost Guy" Christie's resource for getting started: he has a good intro for setting up a tote bin. Scroll down a bit for his instructions on the process and definitely watch his video.

There are also options for vermicomposting outdoors! Things like windrows, pits, trenches, or buried cans all can be effective. Just get in touch and we can discuss your goals and options.

Purchased bins

There are several commercial home bins available and each has pros and cons. If you have an existing bin or are considering purchasing one I'm always glad to consult with you about things to consider! If you're planning on buying a purpose-built bin I encourage you to consider a flow-through fabric bin like the Vermibag (I use several and love them, and if you purchase through that link I get a small compensation), Urban Worm Bag, or the no-longer-available WormInn. Flow-through fabric bins are flexible, breathe well, easy to operate, and usually provide a clean worm-free harvest of castings.

Most commercial bins can be very good worm bins if operated properly. I offer one important caution though about bins with a spigot for draining off "worm tea". Models like the Worm Factory and Can-O-Worms offer a little valve to drain leachate from. As mentioned above, this is actually NOT worm tea but is properly called "leachate" which means water that's run through the bin due to overwatering. A properly maintained bin should not generate leachate, and leachate is NOT a healthful product like worm tea. It is simply runoff from a compost pile and has not been subjected to the full microbial processes needed to make a stable solution that will benefit your plants. That's not to say that these aren't good bins, just do not use them to make runoff thinking that it's a desirable thing to get out of a bin.

Another well-marketed commercial model is the $350 Worm Farm, which is a plastic flow-through bin that some people really like. It's cool, but WAY overpriced. You can make an equally (of not more) effective CFT bin yourself (either a "wheelie-bin" style or a Vermbin CFT). Or for the money you can purchase multiple comparable flow-throughs such as Vermibags or Urban Worm Bags. I'm sure "Worm Farms" are effective systems, but save your money. Just my $.02.

The take-away

Worm bins are like many things in life: lots of things can be made in to a great worm bin, if you're knowledgeable and prepared to meet the worms' needs! Things like purchased bins or plastic totes make things a little easier especially for the beginner still learning from their worms. But people make wonderful worm bins from all kinds of materials, shapes, and reclaimed materials. Bathtub worm bins are an especially whimsical option if you have a large climate-controlled area, but would be too cold to run outdoors here.

I would love to chat with you about your plans for a bin.