Few garden pests appear to be hungrier than slugs and snails; even a relatively small infestation can cause absolute havoc and ruin your carefully cultivated plants. At best, the damage they do is unsightly, and at worst, they can kill your plants off altogether.
However, slugs and snails aren’t invincible, and there are many ways to stop them in their tracks before they make a feast of your garden.
- Use plants that they don’t like – Some plants act as a natural slug and snail repellent. Although they usually like to dine on Hostas, varieties such as ‘Invincible’ (which has very thick leaves), and ‘Halcyon’ (notable for the blue tinge to the foliage) are naturally resistant. If you’re more of a keen functional kitchen gardener, rosemary and fennel are not only slug and snail-unfriendly, they give off a beautiful scent too.
- Leave them no place to hide – As with other natural predators, slugs and snails will do their best to go unseen. They seek shelter under garden furniture, log or stone piles, and especially under large planters. It isn’t practical or desirable to make your garden a wasteland devoid of anything that actually makes it a garden, but being aware of their bolt-holes can be a good first step in controlling them.
Encourage garden visitors such as hedgehogs and song thrushes, as these will help decrease the population. A pond will also encourage toads and newts, who like feasting on the pests. Also, don’t get rid of that woodpile just yet, as it will attract the kind of beetle that’s a natural slug and snail deterrent.
- Get the beers in – Enjoy a beer? Your garden slugs do too. If you’re not keen on the idea of pesticides and pellets, a beer trap is an organic way of keeping the population down. You can buy commercial beer traps, or you can set up your own. The commercial varieties consist of a container with a lid, which you can bury close to plants that seem worst hit, with a gap for the slugs to slide in and drown in the beer. They can’t resist the smell.
- Make life difficult – Don’t throw those egg shells away after breakfast. Anything prickly can make life very difficult for slugs and snails in your garden, so a protective barrier around your precious plants can be an excellent way of making sure that the pests can’t even get to them. A soft-bodied mollusc isn’t going to find it easy to cope with, and will go in search of an easier meal.
Although you could use materials such as sharp sand, or even broken glass, you might want to keep your prickly barrier more soil-friendly; thorn cuttings, or even just pruned twigs can be just as effective. For plant pots that are being attacked, spray the outside the WD40 or similar solvents, which will make the pot surface far too slippery for a slug or snail.
- Give them a shock – An unusual but effective way of deterring slugs and snails can be to put down copper tape. As you know, slugs and snails leave a slime-trail behind them, and the slime reacts with the copper to give the pest a small electric shock, caused by the static electricity. Copper tape is readily available online and in garden centres, and is reasonably priced.
Additionally, it’s versatile enough that you can cordon off entire slug and snail-free areas, by attaching it to plant pots, raised beds, and indeed any area that needs protecting. However, make sure your plant leaves aren’t touching, or the slugs and snails will simply use any plants outside the copper zone as a bridge to those within it!
- Dinner is served – Although this might seem counter-intuitive, making life easy for your mollusc pests will make them less-inclined to head for your precious plants. Leave out piles of greenery in a slug and snail friendly damp area of the garden, and use them as slug and snail traps, before gathering them up and disposing of them safely. This will involve a little extra work on your part in checking your ‘slug and snail café’ regularly, but it will be worth it in reducing your garden’s pest population.
- Nematodes – You might feel slightly squeamish about this, but you’ve probably already got millions of nematodes living in your soil, so adding more of these micro-organisms won’t upset the natural order of your garden. There are thousands of species of these tiny creatures, and some have evolved into natural parasites, infesting a host animal and living off it.
Phasmarhabditis hermaphrodita has become a slug nemesis, and is quite harmless to pets, plants and other wildlife. Within a few days, the infected slug will stop eating your plants, and dies off in about a week. Soil temperatures need to be around 5°C for nematodes to be truly effective, and they’re not terribly successful with surface-dwelling snails, as they don’t tend to come into direct contact with them.
Things not to try: both slug pellets and salt are often offered as effective solutions, and they can be. However, they both upset the natural balance of the soil, and can therefore damage your plants. Pellets, in particular, are dangerous for other wildlife, and particularly the kind you might want to actually encourage into your garden.
As with all pest problems, your slugs and snails aren’t going to disappear overnight, and you might find that you need a combination of methods to get them to manageable levels. It’s unlikely you’ll ever have a completely snail or slug-free garden. However, persistence and vigilance are your friends, and a variety of techniques will help you to make sure that you keep these pests down to manageable levels for good.