Want to get into worm composting but don't want to buy a professionally made bin? This guide is for you!

Since most DIY worm bins are plastic totes, I'll focus on how to prep those bins/buckets for worm habitation.

1. Make sure it is at least 6 inches deep
2. Make sure it has at least 1 square foot of area per pound of worms you'd like to have
3. Opaque is usually best, but a transparent bin can be fun because worms will go along the sides (if left in the dark) and when you turn on the light you can see them for a bit until they burrow into the center to avoid the light. You'll want to keep any transparent bin in the dark for best performance though.

The smallest "worm bin" I've had was about 100 mL (about a 10th of a quart) and it worked alright for the 2 worms I had in there. So if you just want some pet worms you can keep them in something real small. I like this video that shows off a creative mini worm farm idea:

Your worms need to have air. Without air they will die.

If you opt to run your worm bin without a lid, which is totally possible (just keep the worms happy and they won't leave), then of course you don't need any ventilation holes.

But if you are using a lid, make sure it has ventilation on it. I don't put ventilation holes on the side of the bin. Its not a huge deal, but I'd rather put them in the lid (if im even using a lid) so that the worms cant use those ventilation holes to escape. If you have plenty of holes in the lid it will provide all of the air that the worms/bin will need.

I would place 4 1/4" holes in every square foot of lid or have some similar surface to ventilation hole ratio.

An additional precaution you can make is to then cover the ventilation holes with a breathable fabric so insects cannot use them for access to/from the bin.

Bad advice about drainage holes is abundant online.

Your bin does not need drainage holes. This is an optional modification. Ideally, your worm bin never leaks any water. If your bin is leaking water out of the bottom, it is too wet.

Additionally, the liquid coming out the bottom is not worm tea, neither is it worm pee. It is actually called "leachate", and it is not recommended to use on plants.

Drainage holes can be annoying because worms will sometimes use them to escape the bin/go into a water collection bin, where they might die if you don't collect them and put them back into the bin.

HOWEVER, very small drainage holes can still be good to have if you want to have an outward visible indicator that the bin is waterlogged, and/or a way for the bin to release that water.

I use a 1/16" drill bit to put holes big enough for water to drip out, but too small for worms to escape, in the bottom of the bin. (See picture below).

Then you can place something underneath it like a towel, an upside down lid, another bin - whatever.

That way if your bin is waterlogged, it does have the ability to drain and you can see that it's happening.

Again - you shouldn't have water dripping out of the bottom because your worm bin should never be that wet/waterlogged, but its good to have that protection in case it does get too wet.

Vertical migration continuous flow through bins either use a deeper worm bin (2 feet or more is common) or utilize stacking bins (most common for home set ups).

Stacking Bins

To make a stacking bin set up, get a second bin of the same kind (as long as it can "seat" in the other bin), and drill bigger holes into the bottom of the new bin. Something like 16 1/4" holes per square foot.

When your first bin is full, instead of harvesting it, you now remove the top 2-3 inches of material from it, place the second bin (with all the holes in the bottom) on top of the first bin, place the top 2-3 inches back into the top bin, and continue adding food like normal into the second bin.

Make sure the holes in the bottom of the top bin are in contact with the surface of the bottom bin's contents so the worms can get up through the holes.

What will happen is the worms will migrate from the bottom bin into the top one in the pursuit of food. Once the top bin has attracted most the worms, you can then remove the 1st bin (which should be all worm castings and only a few worms) and use the material as finished worm compost/worm castings.

When you've removed and emptied the bottom bin, you then empty out the top bin's contents into the bottom one, and then repeat the whole process.

Alternatively, you can add multiple layers so the worms come up even higher. But I find that as long as they have about a foot of new space to crawl up into from the bottom bin, it will be enough.

Making a DIY CFT BIN

This really deserves a post of its own, which I'll probably make one day, but the true vertical CFT bins are definitely the most complicated to make. 

Since you're not using a removable tray to take out the castings on bottom, you need a way for the castings to fall out the bottom of the bin. Most DIY CFTs will use pipes going across the bottom that are spaced close enough that they hold up the material above them, but far enough that you can use something to agitate/scratch the material between the pipes to make the castings fall out.

Captain Matt with Worm People has made a good video about this, let's check it out.

As a bonus, we can cover submerged worm bins. This is a great option if you want your worms to live and work in your garden or raised bed soil, but still want a way to keep them well fed and happy.

Follow all the steps to make a normal bin, then drill as many 1/4 inch holes around the sides of your bin, or even the bottom, as your patience allows.

These holes will allow worms to travel in and out of your bin into the surrounding soil.

You get a bit of the best of both worlds! A dedicated area for the worms to reproduce and eat lots of food, but they still are able to traverse through your soil, depositing worm castings and doing some aeration while they're at it.

And with submerged bins you could also just dig a hole and use the hole as a worm bin. Though I don't think it's quite as nice, it very much could work.