Slugs & snails in the garden: how to get rid of them
Snails can eat large quantities of fruits and vegetables in the garden overnight. All sorts of home remedies are touted to combat snails, along with traps and pesticides. Some make sense, but some are just myths.
Especially in spring, snails often kill freshly sprouted plants and make it difficult for us to start the new garden year. But, unfortunately, we have to deal with snails in the garden the full year too. Here we’ll show how you can fight slugs & snails and successfully get rid of them.
Fighting snails: how to recognise an infestation
Snails have a rasping tongue, also called a radula. With this, they rasp off food and feeding marks appear on infested plants. These can be located both on the edge of the leaves and in the middle of them. These tracks tend to be roundish, but do not have a firmly defined shape. Often, only the stems remain. Each night, a snail can eat up to 200 square centimetres of lettuce leaves – the equivalent of an entire, large lettuce leaf.
In addition to the eaten leaves, you can always discover slime trails of snails in the garden. The little creatures need enough moisture to move forward – they can cover a distance of about ten centimetres per minute. The slime trails are usually shiny silvery and easy to spot.
Snail eggs likewise provide an indication of the presence and impending infestation. The moist, shiny, white to yellowish egg sacks can be found, for example, in cracks in the soil, in holes in the ground, under plant boxes or under stones. They can be located anywhere that is dark and damp. After about two weeks, the new generation will hatch and soon start to eat tasty plants.
Which snails are protected species?
The Roman snail (Helix pomatia) is a protected species in the UK, because it is endangered. This means it is illegal to injure or kill them.
For other species, the rules are a little vaguer – the field snail (Deroceras reticulatum) or roundback slug (Arion spec.), can and may be combatted if they are a pest to vegetables and fruits, but in ornamental gardens, you should leave them be.
Combatting snails: What really helps?
There are several products designed to fight snails on the market. In addition, home remedy tips are often shared. Unfortunately, not all of them are as helpful as assumed, and some are even harmful to the environment. There are pesticides against snails, which are also called molluscicides. In addition, there’s the possibility of using home remedies and traps to drive away or capture snails. We present the different methods in detail.
Fighting snails naturally
Organic slug pellets
Molluscicides that use the active ingredient ferric phosphate have already received a “very good” eco-test rating several times. Snail pellets made from ferric phosphate are also permitted in organic farming. After ingestion of this molluscicide, the nudibranchs stop feeding, retreat to their hiding place without forming slime, and starve to death after a few days.
How to properly apply snail/slug pellets?
- Application in mild weather
- Early morning or late evening
- Water area beforehand
- Apply evenly around the plants
- Important: Do not lay out in heaps, but distribute in small quantities
- Application rate: 38 grains per square metre
- Maximum 4 applications at an interval of at least 7 days
- Application span: From April to September
- No waiting time until harvest
- Caution: Do not use on Burgundy snails in vegetable beds
You can naturally combat snails and slugs, for example, with the help of snail traps. These allow snails to either be caught alive or rendered harmless. Attractant baits such as moistened oatmeal or wheat bran are recommended only if the snails are collected regularly. Because this will constantly attract new animals to the garden. Beer as an attractant is definitely not recommended, as the very intense smell merely attracts more snails from the surrounding area. You can read about what to look out for and how to build such traps yourself in our article on snail traps.
Home remedies against snails
All sorts of home remedies against snails are touted on the web as helpful, but this is often accompanied by fallacies. These include spreading ash, sawdust, lime or eggshells. Another method takes advantage of the fact that snails do not like to crawl over dry surfaces. Because these would deprive the animals of water. Virgin wool is sold for this purpose, but it works only to a limited extent. Rock dust or bark mulch are not effective against snail infestations, although both are a benefit to the soil. Coffee grounds against snails however is a useful method.
Snails can also be driven away with special plants. You can find out what they are in our article about slug & snail repelling plants.
Nematodes against snails
Nematodes are living threadworms, among which some species are used as beneficial organisms in biological plant protection. In the fight against snails, nematodes of the genus Phasmarhabditis hermaphrodita can be used. They are placed in water and then poured or sprayed.
The nematodes penetrate the snails and infect them with a bacterium. This decomposes the snails, on which the nematodes in turn feed and can multiply in large numbers. The snails stop eating after infection and thus starve to death.
Many harmful snails can be parasitised by Phasmarhabditis hermaphrodita , but burgundy snails are spared. This nematode genus itself is resistant to some molluscicides.
What must be considered when using nematodes against snails?
- Soil temperature should be at least 5 °C, preferably 10 to 25 °C
- Do not allow the substrate to dry out, even 1 to 2 weeks after application
- Application is best 3 to 4 days before sowing or new planting
Most of the available pesticides against snails and slugs are granulated and need to be spread. They are known as slug pellets. Up until recently, most slug pellets contained metaldehyde, but this substance is now banned in the UK as it posed unnecessary risk to garden wildlife. It is also toxic to animals and young children and can contaminate groundwater. There are slug pellets available which contain a much less harmful active ingredient known as ferric phosphate. These are permitted for use in organic farming and are not harmful for plants, garden wildlife, pets or humans.
Destroying and disposing of snails
Dead snails can be added to compost in small quantities. In larger quantities, they belong in normal household waste. Anyone who collects live snails should, of course, not throw them into a neighbour’s garden. Disposal in the forest or along bodies of water also merely shifts the problem. Instead, they can be killed quickly by placing them in boiling water or vinegar solution with a mixing ratio of 60% vinegar and 40% water. Scalding with hot water or sprinkling with salt, on the other hand, is torturous for the animals.
Is it possible to prevent slugs?
If you look carefully in your garden, you’ll notice that some plants do not show signs of slugs or snails feeding. This is because there are a variety of slug and snail resistant plants that can be planted in the garden. These include perennials and ornamental flowers such as the grove violet (Viola riviniana) or the cranesbill (Geranium spec.). Certain vegetables, for example garlic (Allium sativum) or lamb’s lettuce (Valeriana locusta), are also not approached by snails.
Tip: Since these plants are avoided by snails, they can also be used to plant deterrent strips along beds to keep snails out of the garden.
Furthermore, the garden should not be watered in the evening. Indeed, the humid climate would attract the snails from their hiding places. In addition, you should always prepare the seedbeds with fine crumbs and press down sensitive seeds so that snails cannot easily reach them.
Nematodes are useful garden helpers that are also effective against other pests. Fungus gnats may be causing problems in the soil of your houseplants – but not for long after you read our article on fighting fungus gnats.