Slugs and snails are one of the commonest garden plant pests. They are present in large numbers and can quickly eat and destroy a wide range of plants, especially those with young and soft leaves.
There’s probably no need to tell you what they look like. Their silvery trails will tell you where they came from – and where they went to after lunching on leaves of numerous garden plants, including young plants and seedlings, vegetables and hostas. But here are a few interesting, even amazing, facts that will give you some clues as to just what you're up against!
Up to 90% of the slugs in your garden will be hiding underground during the day. On average, 200 slugs live in a cubic metre/yard of soil. That means in an average sized garden there will be up to 15,000 slugs – and then there are the snails! They love mild and damp weather, but they will still be around and hungry in the winter when the temperature stays above 5C (41F) and even during the night in summer.
Holed, or in bad attacks, skeletal or near skeletal foliage. Holed tubers (potatoes, carrots etc) or bulbs. Slime trails are not always present.
No garden will ever be free of slugs and snails. Your approach should be to protect vulnerable plants. But, if you come across a slug or a snail you would be well advised to pick it up and dispose of it. Don’t throw them over the fence – they have a ‘homing’ instinct and will come back!
Although there are numerous species of slugs, not all eat and damage plants. Some are carniverous and even eat other slugs! Many of the damaging slugs spend most of their time living in the soil.
There are many control products that are placed on the surface and act as a barrier to the slugs and snails getting at the plant. These include egg shells, grit and even coal fire ash. These have limited success and are no control for those slugs living in the soil.
Thinly scatter slug pellets on the soil around vulnerable plants, which is effective against all slugs and snails when they are active, during mild, damp periods.
A word for parents and pet owners: We recommend that you keep slug pellets out of the reach of children and pets, both in storage and in use. Do not pile up the pellets under bricks or half grapefruit skins, but scatter thinly as directed on the container.
Some slug controls are applied as a liquid, watered around vulnerable plants. These can will deal with all those slugs that can’t be seen, as well as those slugs and snails that can. Being a liquid, they are invisible to pets and children.
Not effective at surface level, but an option for underground control. Nematodes (minute parasitic worms) can be watered onto the soil and can help control slugs. They penetrate the slug and kill it. They are only effective against slugs, and have no effect on snails. They are available from numerous mail order biological control suppliers, such as Green Gardener.
Some gardeners use beer traps. While these can be effective against slugs, they can also trap rove and other beetles, which are natural predators of slugs.