Components of a Basic Worm Farm

• The main container
• The container’s cover
• Drainage holes
• Liquid collection tray
• Bedding

Successful worm farms contain most or all of these components. Each feature listed above is designed to keep the worms healthy and make collecting their nutrient-rich byproducts simple.

Worm farms do not need to be overly complicated to properly function, however; understanding the function of this basic worm farming system will help make caring for your worms more intuitive.

The main container

The main container must be durable enough to resist biological decomposition and temperature changes. Plastic bins made of HTPE or Poloypropoline are excellent for holding worms. Our example uses 2 10-gallon storage containers stacked inside each other. the bin on top is the main container while the bottom bin collects water from the farm.

Wood containers are sturdy and easy to build yourself. It is essential to waterproof the interior of a wooden worm container. Wood is the most susceptible to decomposing from the inside out, so make sure to line the inside with plastic or sealing spray if you plan to go this route.

Also, the bin must not be chemically reactive to the soil. For example, tin buckets are prone to rust under moist conditions of the worm bin. Metal bins also tend to exaggerate temperature changes if you plan to keep the worm farm outside. In the summer, metal bins will hold onto heat, while in the winter, metal bins will not retain heat.

The container’s cover

There are fewer restrictions for crafting a good worm bin lid. For the lid, you may use these materials:

• cardboard
• straw
• newspaper
• paper bags
• Old t-shirts
• wood
• chemically inert plastic

A lid/cover is necessary for any worm bin for several reasons. Light stresses out worms and a lid that limits light penetration through the soil will help the worms access food that is closer to the surface. Above all else, make sure that the lid is lightweight and does not compress the soil.

Also, if you choose to use a paper cover, remember to replace the paper every few weeks or once the paper becomes saturated with water.

A lid will also conserve moisture in the bin. Especially in areas with circulating air, moisture will continuously evaporate out of the system. The lid will be a barrier between the open air and the soil where water vapor may be trapped and reintroduced to the bin.

Drainage holes

Drainage holes are essential for managing the worm bin’s water capacity. Carefully drill evenly-spaced holes on the underside and/or walls of the main storage bin. I recommend drilling holes in the container’s walls too for better air exchange.

Make the holes large enough to allow water to escape the bin but small enough to contain the soil and worms.

Worms need water to stay healthy but too much of any good thing is dangerous. Worms breathe through their skin and get oxygen as air dissolves into the layer of mucus that coats their body. Too much water will easily drown your worms while too little water will dry them out.

Even with drainage holes, it is fairly easy to overwater your worm farm. Keep the balance of moisture in check with a quick squeeze test. With gardening gloves, squeeze a clump of worm bedding in your hand and watch how much water comes out.

Squeezing out a few drips is perfectly fine. If the clump is mushy and a stream of water comes out, your worm bin is too wet. Manage this by adding more paper/cardboard and taking a break from watering for a week.
Liquid collection tray

Beneath the main container, there should be a way to collect the leachate (worm tea) that drips from the bin. If you are adequately watering the bin, water will accumulate in this tray to use in the garden.

Personally, I stack my main container inside another unmodified storage bin to collect the water. The larger bin also has a watertight spigot installed in the bottom. This makes diluting and harvesting my worm tea very easy.

This water will be rich in nitrogen and microbial activity, so take some time to dilute it before fertilizing your garden with it. A 10:1 dilution is perfect for stretching out the usefulness of your worm tea.

Bedding

The bedding inside the main container should resemble a compost bin with higher concentrations of brown materials than usual. For example, I try to maintain this balance of materials in my personal worm farm:

• Brown materials 50%
• Green Materials 25%
• soil/compost 25%

To clarify, brown materials are high-carbon items like paper, cardboard, and dead leaves. On the flip side, green materials are nitrogen-rich items like food scraps, coffee grounds, and manure.

Maintaining this balance of materials in your worm farm is best for their health. Why? Because worms need a place to retire from eating and do not enjoy being surrounded by food and waste 24/7.

Again, too much of a good thing can cause problems. Too much “brown” will leave little nutrition for your hungry worms or dry them out. On the other extreme, too much green will create a toxic environment that will kill your worms and generate bad odors.

A properly managed worm farm should never smell foul. If this is the case, your worm farm might be going anaerobic or lacking oxygen. You may be able to turn things around with lots of paper/cardboard to soak up the smells and extra water.

Conclusion

Building the worm farm is easy and with this simple design, managing the farm long-term is even easier. You’ll find that this design solves several common problems when it comes to worm farming so you can focus on harvesting free earthworms and organic fertilizer.

Your garden will definitely thank you for providing such nutrient-rich compost, worm tea, and earthworms to the soil. Come harvest time you will be rewarded with equally rich produce and flowers as a reward for all your hard work!

While effective on its own, this simple design may be improved further. Let practicality be your guide, put the health of your worms in mind, and enjoy farming these little wrigglers to your heart’s content.