Looking after your allotment - Slugs and snails

How to deal with them eating your plants

Natural ways

Slugs are eaten by frogs, toads, hedgehogs, centipedes, ground beetles, slowworm and fireflies, so make sure you don’t use any chemical sprays which can harm them. Providing suitable habitat and food will encourage these beneficial creatures to live in your garden or allotment.

Slug killers

Pesticides, based on aluminium sulphate, whilst not strictly organic, are environmentally friendly. They kill slugs and snails on contact with minimal risk to other wildlife or pets. There are commercially available products using aluminium sulphate as active ingredient.

If you must use slug pellets, read the instructions carefully and then follow the recommended application rates. You don’t need many slug pellets to kill the slugs and snails and remember that slug pellets will kill animals that predate on slugs.

Protective Barriers

Protective barriers such as plastic drinks bottles with the bottoms cut off and the screw tops removed to make individual protective cloches. Check for the first few days that a slug hasn’t been trapped inside the bottle.

Self-adhesive slug and snail tape can be purchased that creates a protective barrier around seed trays. It repels slugs and snails by a small electric charge naturally contained in the copper face of the tape.

Slug/snail repellents are available that contain natural yucca extract. These, when sprayed on the ground form a physical barrier which slugs/ snails will not cross. Like most barriers, it will withstand light rain, but will have to be renewed after heavy rain.

Materials such as lime, rough bark, crushed eggshells, wood ash, coffee grinds and gravel are said to make effective slug barriers. Sprinkle on the ground around plants.


Slug traps can be easily made from empty plastic pots e.g. yoghurt pots, buried to half their depth in the soil and filled with water or beer. Slugs will climb up the sides, enter the tub and be killed. These are useful around newly planted seedlings. The trap may catch large black ground beetles which predate slugs and snails, so make sure the lip of the trap is at least 2cm above the soil surface to stop beetles getting in.

Baiting and hand picking

Slugs will inevitably collect in cool damp spots. This fact can be used to advantage as a method of reducing slug populations. A piece of damp cardboard held down with stone, or a piece of carpet, for example, is ideal; just lift it up at regular intervals and dispose of the slugs underneath it by dropping them into a pot of salty water. This is unlikely to reduce the slug populations in the long run, but it can save individual plants, which is most satisfying.

Winter digging

Autumn digging, leaving the soil rough and cloddy while the slugs are still active will allow those species that hibernate to move deep into the soil. If you must dig, do it in the winter while the soil is cold and the slugs are less active. This may also help to kill some slugs, and expose them to predators such as birds. While digging, look out for slug eggs in the soil. These are little clusters of colourless, round eggs, looking rather like small frogspawn or sago.



Last Updated on Wednesday, February 22, 2023