For people who do not want to kill slugs but want to get rid of them and who are ready to put some time into doing so.

1. Awareness

Where do slugs hide? Under things. They like to shelter in dark, damp places. Check under pots, stones and pieces of wood and, most importantly, under plug trays—the perfect slug hotels: lots of dark grooves to hide in by day and a short distance to the restaurant for a tasty seedling dinner by night. Check in and under items that you have just brought into your garden.
What do slugs like to eat? Most plants that humans like to eat… and hostas.
Which are worst? In my experience, the small slugs cause the greatest damage and are the most difficult to see.
When do they feed most? At night-time.
What do slug eggs look like? Little white translucent ball-bearings.
What eats slugs? Hedgehogs, foxes, poultry. Beetles and birds eat slug eggs.

When I discover a slug and think – “just leave it” I remind myself that each one can cause up to €10 worth of damage.

2. Acceptance

  • Slugs fulfill an important role in the natural world. They are a food-source for mammals and birds and contribute significantly to soil fertility as nutrient cyclers and  waste recyclers.
  • There may be tens of thousands of slugs in your garden so it is pointless to think of exterminating them all; they are very mobile and can travel quite a distance so there will always be new arrivals—or returnees from a neigbour’s garden ;-)
  • Remember, we are invading their territory not the other way round and into that territory we plant delicate, exotic and tasty vegetables and flowers that they cannot resist.
  • Grow a little more than you had originally planned to so you can afford some losses (and support biodiversity).

3. Management

Accepting that slugs cannot be eliminated allows you to think about managing their population. Planning and slug-removal activity needs to be systematic and consistent. It can start in advance of planting and, ideally, should continue throughout the year.

4. Removal

The most effective way of reducing the slug population in your garden is to remove the slugs by hand, one-by-one.

  • Identify a place to where you can bring the slugs that is far enough away from any gardens.
  • If you are squeamish about handling them, try to get over it. “Pick’em up quick” and place in a container with a cover so they cannot escape. A dark box or bucket containing some vegetation will keep them happy until they are brought to their new home.
  • Evening time is the best for finding them and especially if it’s wet. Night time (with a torch) is even better but may not be practical.
  • Search from the centre of the growing area outwards. Repeat once a day until you need only do so once per week.
  • Place a plank of wood in the middle of your raised bed before planting; you can then gather those slugs that shelter underneath.
  • Remove eggs when you encounter them.
  • If you are gardening a large area or commercially, then ducks perform a very efficient job of devouring slugs and slug eggs.

5. Defence

  • A protected growing area such as a raised bed lets you focus your attention on defending one area.
  • An area that is surrounded by gravel paths can be better defended as the slugs dislike crawling over dry gritty surfaces.
  • Slugs also dislike crossing copper. Pin a length of copper wire or a copper band around the outside of your raised bed. Copper banding is sold in some garden centres but is very expensive. On the other hand, copper wire is cheaper and can be salvaged from building sites and skips.
  • Encourage birds and beetles who eat slugs eggs.
  • Coffee grinds sprinkled liberally around your plants offer some defence and also act as a fertiliser. Cafés are usually willing to give away their waste coffee grinds in suitably large quantities.
  • Don’t leave stones, cardboard or wood lying around or near your growing area. They provide daytime shelter for slugs.
  • Slugs dislike salt but so does everything else. Salt will kill your plants and wreck your soil so it is best avoid using it.
  • Avoid using straw as a mulch. It works great in hot countries but here it gets damp and provides a cover for slugs.

6. Keep your friends close and your enemies closer

A few years ago I planted a patch of mizuna in my polytunnel. I planted way too much and got fed up of it. One evening I discovered that it had become an enchanted forest for slugs of every size and colour with remarkably little consequence for the surrounding plants. The mizuna patch had become a magnet for them and there they preferred to stay.

If you have the space, think about creating an area that attracts slugs away from your growing area with plants that are equally or more appealing to them. By drawing them to that area you can gather them more easily for weekly removal.

A jug of slugs for removal from the 'magnetic' mizuna patch.

A jug of slugs for removal from the ‘magnetic’ mizuna patch.

Miscellaneous Notes

While snails can damage your crops, they are far fewer in number and easier to find and remove. You can sometimes hear (and see) thrushes bashing them off rocks to get the meat out of the shell.

Slug populations differ from year to year. 2012 was one of the worst I’ve experienced because of (i) the wet summer and (ii) the mild winter that preceded it resulting in fewer eggs and slugs being killed off by frost.

For more information on molluscs, visit the Mollusc Ireland website.

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