Advanced Household Worm Farming

Alright, so I’m sure everyone has read the worm composting 101 post from last week and is ready to move on to some serious worm farming. Right?

Worm bins at Growing Power

If you have been composting with worms for some time now and would like to increase your production, here are some tips to get you started. If you are just getting started check out our Worm Composting 101 post for the basics.

Deciding On Scale

There are a few factors to consider when deciding on the scale of your worm farm. You will need to decide how many pounds of food you’d like to compost each day and then double that weight in worms (generally worms can eat 1/2 their weight in food every day). You can then take that estimate and decide how big you will need your bin to be, or alternatively how many bins you will require. The recommended stocking rate is 1/2 to 1 pound of worms per square foot of bin. Worms primarily live in the top 4-6” of the bin, so a deeper bed does not necessarily require more worms.

For example, say you’d like to compost 4 pounds of food everyday. This will mean you will need 8 pounds of worms. You could house these worms in 2 bins that are 2 x 2 ‘ or one longer bin that is 2 x 4 ft.

Good Bin Design

When you are investing in a larger bin or increasing production, keep harvesting method in mind when choosing a bin design. You will want a bin that makes it easy to harvest your worms and compost easily so that the larger capacity doesn’t become too tedious at harvest time. And if you decide on a stackable system remember is to keep the scale of the bin so that you can easily lift out a finished tray of compost by hand.

Large operation, regular sized bins.

The best option for easy harvesting is a continuous flow design. This is a system in which the bin or piles are set up so that the worms migrate towards the food source and leave the finished compost to be harvested without needing to separate the two. The worms can migrate horizontally or vertically and generally this is done by separating finished compost from the new food with a screen.

For most home based operations a great continuous flow design is a stackable bin that allows the worms to climb up into a new bin as they finish processing the scraps in the lower bins. These are great because you can have a productive operation without taking up a lot of space. There are a couple of popular commercial bins you can purchase such as the Worm Factory and the Can-O-Worms. If you’d rather build your own stackable system you can use these designs using wood or plastic bins.

DIY stackable system

Worm Reproduction

You can fully stock your bins right at the beginning, or if you are short on money but long on time, you can allow your worms to reproduce in the bins. Compost worm populations can be expected to double every 60 to 90 days, when the following conditions are met:

    •  Adequate and continuous food supply
    • Well aerated bedding with moisture content between 70 and 90%
    • Temperatures maintained between 15 and 30oC
    • Initial stocking of at least 1/2 lb/ft2 but not more than 1 lb/ft2

If you’d like to know more about how worms reproduce, All Things Organic has a great article outlining some of the finer details of earthworm biology and reproduction that is well worth a look.

Vermicomposting on the City or Country Farm

If you are looking to compost with worms on a larger scale, to supplement your soil on your farm, there are a lot of great examples and resources out there to help.

Will Allen of Growing Power showing his bounty.

Growing Power is an organization based in Milwaukee, where they also have an inspiring Urban Farm. A big part of their urban farm operations and soil health regime is vermicomposting. They raise worms and compost with them both in bins and in windrows. In the bins they layer worms and partially decomposed compost. Typically it takes the worms 12 weeks to process the compost into castings.

They have over 50 bins which are checked daily to ensure the worms are adequately fed and that the bins are moist. At the end of the 12-week time period, they place a screen over the top of the bin and feed the worms new compost. Using this method, they recover approximately 80 percent of the worms to use in the next worm bin.

All Things Organic also has a wonderful and serious manual to On Farm Vermicomposting and Vermiculture that will tell you everything you ever wanted, and maybe even some things you didn’t want to know about vermicomposting. It outlines several large-scale systems which would be great options for people with more space and wanting to compost in the winter outside.

Where to Buy Worms in HRM:

Happy Worm Farming!

Written by: Garity Chapman, Urban Garden Project Coordinator