How to Build Your Own
Worm Bin
Text by Becky Croston, Master Gardener
Photography by Molly Shurtleff

Assembling
Your Worm Bin

Materials

• Three "Rubbermaid-type" four-gallon to ten-gallon storage bins with one lid. (Sides need to have large enough flat areas near the rim for insertion of vents.)
• Eight empty pop cans for support
• Six round aluminum roofing vents with screens (two-inch or three-inch size)
• Optional - one drain spigot: RV type, or "Raindrip" type

Directions:

1. Drill lots of 3/16-inch holes through the bottoms of two of the bins that are large enough for the worms and excess moisture to go through, without letting too much soil filter through.
2. Drill a hole for the spigot in the third bottom unit (the one without the small holes), or you can skip the spigot and pour the "worm tea" out when it accumulates. This will always be the bottom unit.
3. Stack the bins on top of each other, using the cans to elevate the bins. Using a vent, trace where the bins will be inserted, on the visible upper sides of the bins, so the vents are exposed when you stack the bins. Use a compass to trace where the holes should be cut for the vents; the vents should fit snugly into the holes. Cut the holes with a hole saw, a tin snip or a pair of scissors. Clip the exposed flange that shows on the inside, about every half-inch. Fold these cut sections back so they lock the vents in place.

Assembly:

Optional: the complete three-bin unit can be raised up on top of four inverted plant pots.

1. Start with the bottom unit (empty), then add the middle unit on top of four of the inverted pop cans. Lay a piece of weed fabric (with multiple short slits cut in it) or fine net cloth on the bottom, covering the holes. You don't want the worms falling into the bottom unit, but you want the "tea" to drip through.
2. Place four more inverted cans in the corners of the unit. Fill the level of the vents with starter bedding and food. (Starter bedding consists of shredded, moistened newspapers, about one pound of vermicompost with the worms and food suitable for worms.) Place a piece of weed fabric on the surface. Add the empty top unit and the lid. Feed and moisten as needed.

Use:

If you find you are not getting "tea," you are not feeding the worms enough wet food (composting worms like their food gooey). Instead you can fill all three bins with food and bedding as you would for the middle bin, and have three bins of working vermicompost. When the vermicompost is nearly "done" then push the vermicompost to one side and start new bedding and food in the empty half. Harvest the finished side in a few days when the worms have migrated into the new bedding and food and ageing vermicomposting again.

Article and photos courtesy of Westsound Home and Garden

<< back to composting