Snails

What are Snails?

Snails are part of the molluscs group of animals making them closely related to cockles, mussels, squid and octopus. They are soft bodied animals with no internal skeleton. They specifically belong to a group called gastropods, a name which quite literally means 'Belly Feet' which is quite appropriate for animals which move around on a 'foot' beneath their belly!

There are a number of varieties of snails which are common in gardens but the most common is the common garden snail (Helix aspersa). Banded snails, Cepaea species, can be just as numerous but damage plants less. They are smaller in size and often brightly banded in brown, yellow and white and , may also be numerous, but these are less damaging to plants.

Do they harm plants?

Yes.

What damage do they cause?

Snails left to their own devices can strip young plants and seedlings to a stump overnight. They leave irregular shaped holes with smooth edges on leaves and leave a tell tale give away, slime trail. (This could also be slugs). Snails differ from slugs in the fact that they are dormant throughout the winter months. You may see them grouping together in protected places like crevices or plant pots.

Do they affect certain plants?

Seedlings and other plants with new soft growth are particularly affected but generally many ornamental plants and vegetables are affected. Herbaceous plants when sprouting are particularly at risk.

Is there any time of year particularly at risk from Snails?

Snails are dormant during the winter therefore Spring and to a lesser extent Summer are the main times to be aware of them.

How do I get rid of them?

Non-chemical control

Nematodes which work for slugs do not tend to have the same affect for snails. In my experience, there are three main ways to reduce the snail/slug population in your garden:

Plants, especially varieties of Hosta benefit from being grown in pots where the leaves do not touch other plants or hard landscaping features.
Go out on a damp evening in Spring and physically pick the slugs off the plants. Do this a couple of nights on the run and it will significantly reduce the problem in your garden.
Encourage predatorily wildlife into your garden like hedgehogs, frogs and toads, thrushes, slow worms and ground beetles.

Other people will swear by many other tips and techniques which include the following:

Beer traps either home made from jam jars sunk in the ground or bought ones that sit on the soil.
Grapefruit or melon skins upturned on the soil near ‘at risk’ plants. (Check them each morning).
Protect seedlings or freshly transplanted plants with a clear plastic bottle ‘cloche’.
Physical barriers: Eggshell, grit, or other sharp mulches placed around plants at risk.
If you come across snails in winter, put them on a ground based bird table or on the lawn. Thrushes will enjoy the meal you have provided.

Chemical control

Slug pellets are generally the chosen form of chemical attack in gardens and their green-turquoise pellets are seen all over the country in an effort to stop slugs eating prized plants.

If you feel you have to use slug pellets or a liquid form of pellet read the instructions first as using them not as advised will have no effect on the slugs. They need to be spread thinly around the vulnerable plants and seedlings.

Pellets based on metaldehyde generally are not harmful to wildlife, pets or children unless eaten in quantities but it is worth thinking about the implications of eating larger quantities by pets or children for example as the results can be serious. Severe abdominal pain, nausea, vomiting, diarrhoea, fever, convulsions, coma, and persistent memory loss and in extreme cases; unconsciousness and eventual death has been recorded. Pellets based on aluminium sulphate and ferrous phosphate are less toxic but natural methods ideally would be a first choice.

Most plants once they have chance to establish are able to resist damage from snails unless there is a particularly large population.

Always use chemicals as instructed on the label and wear any gloves etc. when necessary.

Snail under the lip of a pot during the day