Plant Doctor Archive

Too much snail bait?

I'VE been told slug and snail baits must be used sparingly as they can kill plants. I normally give a good-sized sprinkle of bait (a small handful spread out over about 1m or so) along the edge of the path next to the bed concerned. On pots, about 20cm wide, I would use six or seven pieces of bait. The snails still appear, so I'm just wondering if I can be a bit more "reckless".

I'VE never come across any information that suggests slug and snail baits might adversely affect plant growth, as long as you use them according to the label recommendations. On the other hand, slugs and snails are probably the most destructive of garden pests and there's little doubt that judicious use of baits can be very effective at reducing their numbers.

It sounds to me as if you're applying them at about the right rate, though that can vary depending on the type you're using. Most baits on the market fit into one of two categories. There's the traditional pellet-type bait, like Blitzem Pellets, which doesn't last too well after rain, but it's relatively cheap and does work. The pellets are quite large and the recommended rate of application is usually 20 grams per square metre, which equates to around one piece of bait every 5cm.

The other type of bait is the granular form, like Blitzem Granules and Baysol, which is usually more costly, but the granules are quite a bit smaller than pellets so you can spread them further. They're also more rain resistant. I prefer to use this type, as Baysol in particular lasts at least two weeks, even in wet weather, and the small granules are very easy to sprinkle evenly.

When applying baits make sure you get them close to the plants you need to protect, as small slugs can hide during the day in the soil or under pots to come out at night and do their worst. Snails can hide in dry places overnight such as at the base of sheds, fences, walls or under piles of rubbish.

For best effect, apply bait more regularly, say every two weeks, rather than more of it. After a while you should find you can cut back and still get good control, but remember, cool damp weather in spring and autumn is when you really need to be on your guard.

Lastly, watch out for pets, as poisoning by slug and snail baits is quite common. Most, but not all, dogs are put off by the animal deterrents in baits.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.