Hello, Imogen here. Recent FoAM apprentice. Long time worm farmer.

I built a worm farm for FoAM last week. Here's how I did it plus I'll add some maintenance tips and further references.

First up, it's good to know that these are red wiggler worms, not to be confused with earthworms. While both types of worms break down organic matter, earthworms hang out at a deeper level of the soil. Whereas red wigglers live at the surface of the soil, and are a more aggressive eater: devouring manure, dead leaf matter, you name it. So these are the worms used for composting, their worm castings create rich fertiliser for plants to grow.

You can buy a worm farm from your gardening store, however it is way more fun to make your own. Worm farms can be as simple as a single container in which you put your food scraps. They can exist vertically (stacked, so that worms move up and down from layer to layer), or they can also exist horizontally - ie you can create a long farm, often people use bath tubs. Drainage is very important as worms also create liquid (called worm tea). This should be drained out of the worm farm so that the worms don't drown in their own wee (yuk). This liquid is also great fertiliser, and should be added to plants watered down to the colour of weak tea.

So! Your worm farm design is not only about aesthetics (what you want the worm farm to look like, maybe you want it to also function as a bench top for pot plants or a seat), but it's also about what materials you have at your disposal and how much you are willing to spend on buying bits and pieces. After chatting to FoAM, we had decided on a bath tub design, with a nice wooden lid (perhaps an old door) which could provide a flat surface for plants.

I hunted around Brussels looking for a bath tub, but to no avail, it just wasn't second hand bath tub season at the flea markets. So Plan B: I decided that I'd buy big plastic tubs which stack into each other (you can buy them at hardware store or office supply stores). I decided on a vertical design like this http://www.tumbleweed.com.au/WormFarming.aspx . If you're going to go for layers, I like using a 3 layer system, where you have the top 2 layers to interchange between the upper feeding level and lower 'manifesting' level, and the 3rd bottom layer acting as a drainage system.

Purchase:
3 x blue plastic storage containers
1 x lid
5 x 15cm wooden blocks
Threaded tank inlet and washers

Total cost: about 50 Euro (could have been cheaper but I had to shop at the inner city hardware store, which was an experience in itself as none of the staff spoke English. Trying to ask for / draw / mime a threaded tank inlet was like playing charades in the dark).

Step 1:

Drill some very small holes (about 1/16“) around the top of the containers to help with ventilation.