What Is Vermicomposting?
Vermicomposting uses a wormery and composting worms to turn suitable kitchen scraps into a rich, crumbly material and liquid that can be diluted for plants. It is a compact option for gardens, balconies and allotments, but success depends on keeping the worms cool, fed and not too wet.
A wormery is a lidded container with bedding, air holes and usually a tray to collect excess liquid. It uses brandling worms, often called tiger worms, rather than ordinary garden earthworms. Brandlings live naturally in decaying organic matter and are well suited to processing food scraps near the surface. Buy them from a reputable garden supplier, or obtain a starter culture from another wormery. Place the wormery in shade, protected from strong sun, heavy rain and frost. A sheltered spot beside a shed, greenhouse or covered patio works well. In summer, check that the container is not heating up; in colder parts of Scotland, provide extra insulation and shelter during winter.
Set up the base with moist, springy bedding such as torn plain cardboard, shredded paper, coir or partly rotted leaf mould. Squeeze a handful: it should feel like a wrung-out sponge, not drip water. Add a thin layer of finished garden compost or a little soil to introduce grit, then place the worms on top and leave them for a day to settle. Start feeding with a small handful of chopped vegetable peelings, tea leaves, coffee grounds, crushed eggshells and soft fruit scraps. Cover food with bedding or a sheet of damp cardboard. The cover keeps conditions dark and discourages small flies. Keep the lid on, while ensuring vents remain clear for air circulation.
Feed little and often at first. Add new scraps only when most of the previous food has been broken down, then gradually increase quantities as the worm population settles. Chop tougher scraps into small pieces to speed processing, and freeze then thaw surplus peelings if you want them to soften before use. Avoid large amounts of citrus peel, onion, garlic, oily food, meat, fish, dairy products and cooked meals, as these can smell, attract pests or upset the balance. Keep a small container in the kitchen and empty it into the wormery every few days. If you are away, add bedding and a modest feed beforehand rather than overloading the bin.
Check moisture, temperature and smell each week. A healthy wormery smells earthy and contains active worms near the food. If it is soggy, add dry torn cardboard, remove any pooled liquid and pause feeding briefly. If it is dry, lightly moisten the bedding with water, preferably from a water butt, without flooding it. If fruit flies appear, bury scraps more deeply and add a thicker bedding cover. In hot weather, move the wormery into deeper shade and offer moist bedding; never leave it in direct sun. During a cold spell, wrap the outside with breathable insulation and reduce feeding, because worms process food slowly when chilled.
Harvest vermicompost when most bedding has become dark, fine and earthy. Move fresh food to one side for a week or two, encouraging worms to gather there, then remove finished material from the other side. Alternatively, tip small batches onto a sheet in subdued light and let worms move away from the exposed surface before lifting the compost gradually. Return any worms and unprocessed material to fresh bedding. Use the finished material as a light top-dressing around container plants, seedlings and established vegetables, or mix a small amount into peat-free multipurpose compost. Do not treat it as a complete replacement for all compost in a large bed; wormeries make relatively small but valuable quantities.
Use the collected liquid cautiously. Liquid from a wormery is often drainage water rather than a consistently made plant feed, so it varies in strength and quality. If it smells unpleasant, is very dark or has been standing for a long time, add it to the compost heap rather than applying it to plants. When it is fresh and smells mild, dilute it generously with water before using it on the soil around established plants. Avoid applying it to seedlings or leaves. Clean the collection tray regularly and make sure excess liquid can escape, because a waterlogged wormery is more harmful to worms than a slightly dry one. A balanced wormery prioritises worm welfare over maximum output.
Frequently asked questions
Can I put garden worms into a wormery?
It is best to use brandling or tiger worms, which live in composting material and tolerate the conditions inside a wormery. Common earthworms from garden soil usually prefer deeper, cooler soil and may not thrive. A starter culture from a garden centre or another established wormery gives the container the right species and a reliable beginning.
Why does my wormery smell unpleasant?
An unpleasant smell usually means there is too much food, too much moisture or too little air. Remove any rotting excess, add dry shredded cardboard, check drainage and leave the wormery without further food until conditions improve. Feed smaller portions afterwards. Keep meat, dairy, oily scraps and cooked food out, as these are common causes of problems.
Can vermicompost be used for seedlings?
Yes, but use a modest amount mixed through peat-free multipurpose compost rather than sowing directly into pure vermicompost. Seedlings need an open, even medium, and rich material can be too variable for tiny roots. Sieve any coarse pieces if desired, and save the remainder for top-dressing pots, vegetables or flowering plants once they are established.
General guidance for UK home gardens and allotments. Conditions vary by region, soil and season; the RHS or a local garden centre can give site-specific advice. Page updated 19 Sep 2026.