Britain has nearly 30 species of earthworm about 16 of these are likely to be found in gardens. They vary in size and colour, all help create good soil structure and fertility.

Earthworms (<i>Eisenia</i> species) in compost
Earthworms (Eisenia species) in compost

Quick facts

Earthworms eat decaying plant material, helping create healthy soils
Britain has about 16 species of earthworms likely to be found in gardens
Earthworms occur in most soils
Some earthworms can be used in wormeries to make compost
Worm casts can occur on lawns

What do earthworms do?

Earthworms are a familiar sight to gardeners, as an important part of a healthy garden ecosystem they help create and maintain healthy garden soils:

  • Earthworms can be active throughout the year but are usually dormant (quiescent) during cold or hot and dry weather
  • Earthworms occur in most soils, but are scarce in soils that are extremely acidic or prone to water logging
  • There is no need to introduce earthworms as they are usually present at natural densities and will colonise new gardens
  • Earthworms eat decaying plant material and do not damage growing plants. They are important to soil structure and fertility
  • Some earthworms emerge at night to feed on dead plant material on the surface, and will pull fallen leaves and other plant debris into their tunnels
  • Some species such as Allolobophora nocturnal, A. long and Lumbricus terrestris live in permanent burrows and it is mainly these species that produce worm casts on the surface

Find out more about earthworms and participate in earthworm research at Earthworm Watch and the Earthworm Society of Britain (links to external websites)

Specialist species and wormeries

Some earthworm species live in accumulations of organic matter, such as compost heaps. One such species is Eisenia fetida (brandling or tiger worm), recognisable by its stripy appearance, another is Dendrobaena veneta. These are the species most commonly used in wormeries, as their feeding activities speed up the composting process.


Pot worms (Enchytraeidae)

Pot worms sometimes referred to as white worms, are closely related to earthworms, but are usually much smaller and most species are pale whitish in colour. They can look similar to some fly larvae. The biology of these animals is not well known. They are often abundant in decaying organic matter, especially if it is damp. Like the larger earthworms, they feed on and help break down decaying organic matter and will not cause any damage to living plants. Some further information on these worms can be found at iNaturalistUK .

Worm casts

Worm casts consist of soil and undigested material excreted by the worms as they feed on organic matter. More information on Worm casts on lawns and gravel paths.

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