What is a wormery and how can it benefit your garden?

Published: January 20, 2021 · Updated: January 25, 2021

wormery compost bin in organic Australian garden with Feed Me worm sign, sustainable living and zero waste lifestyle Photo by HollyHarry/Shutterstock

If you’ve ever made a compost bin or pile for your yard, you’re already halfway to having a functioning wormery. But while compost is common, you may have never even heard of a wormery. This lesser-known version of the same idea—breaking down food and plant waste—is actually faster with a better outcome, all via the added power of specialized composting worms. If you want to try one for yourself, it’s a simple project to make at home to start adding benefits to your yard or garden. Just note that because some earthworms are considered invasive, the resulting compost should only be used in contained gardens.

How a wormery works and how it helps

Wormeries are different from traditional compost bins in that they typically have two or three interlocking compartments or trays, each with its own purpose. While you can make a compost bin out of almost any enclosed container, or even just create a compost pile in your yard, wormeries keep the nutritiously-dense compost material and the beneficial waste water contained so that all of it can be used to fertilize your garden. And adding the worms makes a huge difference. Composting worms can eat up to half of their body weight every single day. They’ll make quick work of your food scraps and plant waste and quickly turn it into compost that will make your garden healthier than it’s ever been.

A wormery can be made any time of year and used, with slight modifications, no matter the season. If you make your wormery in the winter, it gives you time to get the worms used to their new environment. Once they start producing compost, you can scatter it over your garden beds and any soil in your yard where you plan to plant come springtime. This is a great pre-planting step for making your soil ultra-rich and ready to grow. Wormery waste water can be collected and poured over house plants, indoor herbs, or garden beds for a nutrition boost.

How to make your own wormery

Find a set of boxes that can lock together, creating a stacked set of two or three compartments. Two will work just fine for a smaller set-up, but the most effective wormery will have three compartments. These should be able to be unlatched and separated so you can open each compartment to remove compost material or water.

1. In the lowest compartment, drill small holes in the lid that connects to the box above it. The lowest compartment will be left empty, and is where waste water will be collected.

2. Drill 1/4″ holes along the top of the other two compartments, spaced about 2″ apart. Drill a single row of similar holes in the bottom of each tray. These will allow the waste water to pass through to the bottom tray.

3. Now here’s the beauty of the three-tray system. Once your holes are drilled, add a 3″ layer of bedding (compost, fibrous material, or shredded paper and leaves) to the top compartment.

4. Add your composting worms and a small layer of kitchen waste on top. Start with just a bit so the worms adjust to their environment, then add more food as they consume it. After a while, they’ll be comfortable with more at once, but never overload the wormery to the point that air can’t circulate. That’s part of the composting process. You can add kitchen scraps each day as you have them.

5. Once the top tray is filled with compost, swap it with the middle tray, and use that one for your scraps. The worms will travel through the holes into the tray with the scraps, and you can then empty out the compost material to use as you please, leaving that tray empty and ready to repeat the cycle.

Tips and tricks

  • To make worms happiest, keep their environment temperate, dark, moist (but not waterlogged), and make sure air is circulating continuously. During the winter, it’s best to place the wormery somewhere not fully outside, whether that’s in a garage, basement, shed, or under a deck. In the summer, keep it in a shady spot away from direct sunlight.
  • If properly maintained, your wormery should never smell terrible, just a bit earthy. Having two or three compartments helps with this, as you’ll collect the waste water separately (make sure to empty it often). With a clamped lid and small air holes, little smell should escape. But if your wormery is getting pungent, try putting in less waste for a bit so that the composting compartment doesn’t get overwhelmed and the worms can break everything down promptly. Avoid adding meat, dairy, or too many allium vegetables like onion and garlic. These can be smellier or attract flies, and worms won’t digest them easily.
  • Though it’s tempting, don’t just go hunting for earthworms in the garden! While they benefit your garden in other ways, they’re slower eaters and won’t be as effective. You can buy specialized composting worms online (and in many gardening shops).

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