Categories: The Eco Garden

Organic slug & snail treatment


Our mild damp UK climate offers the perfect breeding ground for every gardener’s worst enemy – slugs and snails. Our winters are far too soft on these tiny molluscs. Slugs and snails are intolerant of dry conditions and prefer to move about on damp and sticky surfaces. Is it any wonder that a night of rain during dry spells is both a blessing and a curse?

Conventional slug pellets application

Most of us at some point, have used slug pellets to control slug and snail numbers in our gardens and allotments. Although this method seems to work, often the next day you’ll find many dead slugs scattered across the ground. It only scratches the surface of the problem. Firstly we must understand what we are up against. Any 1-metre square patch of ground may contain between 100-250 individual slugs. A dozen or so dead slugs the day after the assault is a superficial victory.

Another problem with the use of chemical control such as the traditional blue slug pellets (Metaldehyde) on our allotments is the problem they present to other friendly garden dwellers. Many predators that eat pelleted slugs will die or become very sick. This has led to a worrying drop in the amount of natural slug and snail predators in the UK.

An organic approved method – Ferric Phosphate

When slug and snail number get out of control, I tend to reach for organic slug pellets. Ferric Phosphate-based pellets are a very effective treatment. They will permanently shut down the slug’s digestive system. This will result in a loss of appetite and eventual death. There are a number of advantages to using this method. Firstly, this will only affect snails and slugs and is not toxic to any other creature. Secondly, the slugs usually bury themselves, so no dead bodies to deal with. Also, Ferric Phosphate will actually feed the soil.

The only negative thing about using Ferric Phosphate is that they are so effective, that there will be very few slugs left for other predators to feed upon. I tend to only use them for population control.

You can buy organic slug pellets online from Thompson & Morgan.

Natural slug & snail control

Our slug and snail populations are rising in the UK as their natural predators decline in numbers. So a good step in the right direction is to encourage the predators back into our gardens.

Useful predators

  • Birds
    • Thrushes
    • Blackbirds
    • Robins
    • Starlings
    • Crows
  • Amphibians
    • Frogs
    • Toads
  • Others
    • Carabid Beetle
    • Hedgehogs
    • Badgers
    • Ducks
    • Chickens

By installing bird boxes, groundcover and other wildlife-friendly habits, you will be encouraging such allies to set up camp in your garden. The Carabid beetle is an effective predator against slugs and snails and can be ‘trapped’ by the installation of a moat around your borders. The outer sides of the moat can be built using plastic lawn edging to prevent the arriving beetles from escaping. You must provide cover for the beetles as they are not at the top of the food chain. A few roof tiles will do for them to hide beneath. Do bare in mind, if slugs become somewhat of a rarity in your border, let the beetles escape back out into the garden to prevent them from starving and give them the opportunity to breed and hunt.

Other treatments

Beer traps have been used a lot in the past, although they do require quite a lot of work – emptying and refilling should be done every few days or so. Also, in order for this method to be effective, you should place 1 beer trap per square metre of ground.

As mentions before, slugs don’t like dry conditions. I have recently observed that they even re-use their old slimy tracks to travel around to conserve against loss of moisture – life or death to a mollusc. A good method for limiting slug damage is to create ‘dry areas’ around your most vulnerable plants. The application of a good layer of rough or dry material should put even the hungriest slugs or snail off its lunch:

Drying methods

  • Broken eggshells
  • Copper rings or collars (they do work!)
  • Ashes
  • Spent coffee granules (they don’t like the smell or texture)
  • Sharp sand

Why not try…

  • Cultivate your soil during dry and hot weather to kill and/or expose slug populations
  • Mow your lawns at night – short grass is a good surface for slugs to move around on, especially in the cool of the night!
  • Ensure that there aren’t too many cracks or crevices in your soil where slugs and snails can easily burrow down and hide from the heat of the sun or natural predators.
  • Purchase nematodes to control slug and snail populations.
James Middleton

An obsessive gardener since 1982. Day-time job - web designer and developer and University lecturer.

Published by
James Middleton
Tags: Eco-friendly gardeningSlug control

Recent Posts

Orchids (Phalaenopsis): Care 5 Step Guide

Getting the most out of your Phalaenopis orchid plants. Orchid care: make your orchid bloom all year. Repotting and fertilizer…

12 months ago

Non-toxic plants for baby & pica friendly gardening

A long list of non-toxic plants to grow in your garden and on your windowsill. Keep your babies and children…

4 years ago

Weird & attractive vegetables to grow this year

An usual assortment of great tasting and nutritious vegetables that will also make great additions to the ornamental border as…

4 years ago

Grow your own – why bother? [An Exposé]

Improve you health and happiness levels by growing your own vegetables on your allotment plot this year.

4 years ago

Baking soda – Organic mildew treatment – courgettes, pumpkins & cucumbers

Get on top of that powdery mildew from your squashes with a simple and organic solution that you are bound…

5 years ago

Nettle feed – free organic fertiliser [how to guide]

You hate nettles, but love healthy vegetables and flowers. Right? While stinging nettles do so well, your beloved garden plants require…

5 years ago