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

 

Converting a Plastic Tote into a Worm Farm

As long as worms have air, water, and food, they wouldn't know the difference whether or not they were just in a big pile of organic matter on the ground, or a fancy worm bin.

The worm bin is mostly for your convenience to keep all of your worms and the contents of the worm bin in a confined location.

I've seen people use things like old refrigerators/freezers and old bathtubs, but most of people doing DIY bins go for plastic totes. Usually between the 5 gallon to 50 gallon range - so most of this post will be geared towards those using plastic bins.

Things to look for when purchasing a bin for use as a worm bin:

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. You probably want it to be able to hold at least 5 gallons total, but I prefer the 10-20 gallon range.
   

4. Opaque is usually best. 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 can have worms live in a bin that's shorter, or smaller, but you won't see much results from those bins. You won't be worm composting as much as you just have some pet worms. But if that's your thing, go for it!

Ventilation holes

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

I never 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.

In, for example, a lid thats 1 foot by 3 feet, I would put about 10 1/2 inch holes drilled into it.

You can also just cut out a section of it, too.

Additionally, if you want to help keep fruit flies out, you can lay a breathable fabric/wire mesh over the bin to allow airflow, but prevent insects from finding the bin, like in the picture above.

Drainage Holes

Bad advice about drainage holes is abundant online.

Your bin does not need drainage holes. 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.

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.

 

Converting a Single Bin Worm Farm into a Stacking System

From here you could leave your bin as-is and it would be a "batch" system. You will add food into the plastic bin until it is full and the worms have eaten everything, and then you will harvest it all at once and restart. Very simple.

To make harvesting worm castings easier, people will often modify their DIY bins further and convert it into a stacking tray system.

In addition to the first plastic bin that you have, you can get a second bin (preferably the same bin so the bottom of the second one can fit into the first one), and drill bigger holes into the bottom of it. 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 filled up as well, most all of the worms should be in it. 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.

In theory this works well, but in practice I usually find that there's still a lot of worms in the bottom tray and you have to harvest it as if it were a batch system anyway - which kind of defeats the purpose, but it still definitely does help get a lot of worms out of the bottom bin.

Creating a Continuous Flow Through (CFT) Bin

If you're new to worm composting I wouldn't worry about trying to make a bin like this. Get the practice/skill of worm composting down first before you put a lot of time/effort into making a CFT bin.

A CFT works similar to a stacking system, but rather than having distinct layers, its all one continuous flow.

The concept is that you make a worm bin that has had the bottom removed and replaced with something that will keep the contents of the worm bin from falling out on their own, but will let some of it fall out when you agitate it.

That way you can continuously remove worm castings from the bottom of the bin, while adding food at the top. Harvesting will be the easiest in this set up, but the bins are difficult to make and you might as well get a professionally done one like the Urban Worm Bag.

Creating an "In Ground Worm Bin"

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.

Hope this information helps! Happy worming!