Worm Composting 101: How to Make a Simple Worm Bin


How to start a worm compost!

Wonderful wiggling worms are the starting point for healthy soil and can create truly awesome compost. Put worms to work in your garden by making your own wormery. It’s easy and will yield nutritious worm compost to enrich your soil. In this short video, we’ll show you how to make a wormery.

A wormery (or worm composter) is an inexpensive project that will produce nutrient-rich compost and liquid fertilizer. Wormeries don’t smell, are great for small gardens, and are a fun way for kids to learn about composting.

Make a Simple Wormery

A wormery is made up of at least two compartments. The bottom compartment collects any liquid that is produced. The top compartment is where the worms live and eat, and is also where your compost will be made. Using three trays instead of two makes it easier to collect the worm compost. Your wormery will also need a lid to prevent it from drying out, or flooding during rain.

The trays we’re using are 16x20in and 8in deep. You’ll also need a plastic faucet , a drill and drill bits.

Carefully cut or drill a hole in the bottom tray to fit the faucet snugly. Make the hole as low as possible in the tray so that liquid doesn’t pool in the bottom. Raise the wormery up on bricks to make it easier to drain the liquid if necessary.

In the top two trays, drill quarter inch holes about every two inches all over the base of both trays. The holes will allow the liquid produced by the worms to drip down into the collection tray at the bottom. Once a tray is full of worm compost, worms will migrate up through the holes into a new tray.

Drill a single row of holes near the top of both trays at the same size and spacing as above to improve ventilation.

Adding the Worms

Only use specific composting worms in your wormery. Most garden earthworms are slow at composting. You can order composting worms online.

Line the tray with a three-inch thick layer of bedding material such as dampened coir (coconut) fiber or good quality compost. Add your worms and they will soon bury themselves into their bedding. They spread a layer of kitchen waste on top—no more than a couple of inches thick to start with. You can also place a layer of burlap on top to keep your worms extra cozy. Leave the wormery for a week before adding any more food to allow the worms to settle into their new home.

Looking After Your Wormery

Position your wormery somewhere shady and as close to room temperature as you can. Worms like moist, warm conditions. Move the wormery indoors for winter, for instance into a garage or outbuilding.

Add small amounts of vegetable and fruit scraps at a time, otherwise there may be an odor that will attract flies. Don’t add meat or other animal products. Large amounts of citrus peel and alliums like onion and garlic will make conditions too acidic for your worms. You can add small amounts of weeds and leaves, and shredded, non-glossy newspaper or torn-up cardboard.

Once the top tray is full, swap it with the empty middle tray and start filling that instead. The worms will work their way up through the holes to the new tray. The full tray will then be ready for collection.

Using Worm Compost and Liquid Fertilizer

The worm compost or castings work great as a soil conditioner or a nutrient-rich ingredient for potting mixes.

Drain the liquid (often known as worm tea) from the bottom tray whenever it collects. Mix one part of the liquid with ten parts water to use as a nutritious liquid feed for your plants.

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About The Author

Benedict Vanheems

Benedict Vanheems is the author of GrowVeg and a lifelong gardener with a BSc and an RHS General Certificate in horticulture. Read More from Benedict Vanheems

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Mary Beth (not verified)

2 years 9 months ago

When you swap trays and begin using the empty tray, do you add bedding?

Yes, put two to three inches of bedding in the empty tray and add your kitchen scraps on top. The bedding will give the worms somewhere to hide while they break down the fresh scraps!

Tiffany (not verified)

2 years 10 months ago

I’m looking for bins like the ones in your video that nest on top of each other. Do you happen to know the product type and where to purchase them?

Tina (not verified)

4 years 2 months ago

How about an "ant moat"? A container of water (which requires frequent re-filling), or better yet, DE (diatomaceous earth). Put the base of the legs in the stuff-of-choice so that the ants would have to crawl through it to get to the prize. I use DE at the base of my dining-room table, and at the base of my laundry hamper. No more ants on the table or in the laundry.

Anna (not verified)

4 years 2 months ago

All well and good until you factor in Fire Ants. Any ideas?

Ants prefer much drier conditions than worms, so keeping your worm bed nice and moist (assuming good drainage) is a good start. 

Perhaps putting the wormery up on a table and smearing something sticky or slippery around the legs might work? Try setting up a perimeter of diatomaceous earth on the ground around your bin – this should greatly harm any ants that try to cross it, since it is essentially like a field of broken glass for bugs (ouch!).