Science Says This Watering Schedule Is 'As Good As Slug Pellets'

For years now, UK gardeners have been discouraged from using slug pellets, which can harm wildlife, in their gardens.

After all, only about nine of the 44 species in the UK actually eat your veggies. And their presence in your backyard is key to feeding our dwindling bird population, too. 

Still, there’s no denying that the clash between gardeners and munching molluscs continues. Some green-fingered gurus have previously recommended using garlic or tinfoil to help you stand your (literal) ground in these backyard battles; even a melon could help. 

And it turns out that when you water your garden matters, too. 

Water your garden in the morning to stop slugs in their slimy tracks 

According to Gardener’s World, watering your garden in the morning helps to block slugs’ path at night (when slugs tend to eat their dinner).

“This ensures that the soil has dried out by the evening, when slugs are most active. Wet soil at night can create a slug highway between plants,” the publication shared. 

The Royal Horticultural Society (RHS) agrees. 

“There has been a study that showed that switching from watering in the evening to watering in the morning can provide as much protection as slug pellets,” their site reads. 

Indeed, research published in Agriculture, Ecosystems & Environment found that slug leaf consumption over the course of their study was 60% in untreated areas, and shrunk to 12% in both patches watered in the morning and those covered in metaldehyde pellets. 

“Morning irrigation thus gave a level of protection against slug damage as good as metaldehyde pellets combined with evening irrigation,” the paper said.

Metaldehyde pellets have been banned in the UK since 2022 because of the threat they pose to wildlife. Most modern pellets rely on lower-toxicity ferric phosphate instead, which kills slugs through iron poisoning, but the RHS maintains that keeping slugs alive when you can is best for your garden overall.

The RHS said that this works because “if you water in the evening, when the majority of slugs are most active, you’ve created a nice wet film that they can happily travel over.”

Water applied in the morning, meanwhile, is mostly gone by nighttime.

How else can I get rid of slugs without killing them? 

According to the RHS, encouraging biodiversity in your garden can aid natural slug control. You can also conduct torchlit searches at night to find and manually remove any offending critters. 

Some woody, waxy, and generally tough-to-chew plants will repel them, too. 

But while the jury’s out on eggshells, copper tape, and pine bark, there does seem to be some data backing a simple morning watering sesh.