Build Your Own Worm Composting Bin: Indoor Vermiculture Step-by-Step

Vermiculture (worm composting) transforms kitchen scraps into premium fertilizer indoors — low odor, low space, high reward. Here's how to build a bin from scratch.

Bin Material: Wood vs. Plastic

• Plastic: Light, easy to drill, but retains moisture — drill extra ventilation holes. Use opaque, dark bins (worms hate light). Storage totes work well.
• Wood: Breathes naturally, buffers moisture, stays dark. Use untreated, natural wood only (chemicals kill worms). Repurpose drawers, cabinets, trunks.

Sizing

1 sq ft surface area per lb of daily food waste. Depth: 8–12" (worms won't go deeper than 24"). Galvanized nails for wood.

Ventilation & Drainage

• Bottom: 10–25 holes (¼–⅙") for leachate drainage.
• Sides: 4–6 holes for airflow.
• Elevate on bricks/planks over a catch tray.
• Lid: solid for outdoors; drilled for indoors. Cover with burlap/dark plastic if needed.

Bedding

Shredded newspaper, cardboard, leaves, straw, dead plants — soaked, wrung to damp (not dripping). Add grit/soil for gizzard function. Vary materials for nutrient diversity. Top with damp cardboard — worms love it.

Feeding & Placement

• Bury food under bedding (rotate spots). No meat, dairy, oils, citrus excess, plastics.
• Location: 55–77°F, no sun/rain/frost. Under sink, basement, garage, shaded balcony.

Harvest

When bin is mostly castings, migrate worms to fresh bedding (stack new bin atop old; worms climb up). Harvest castings — black gold for plants.