Is bark mulch effective in controlling slugs and snails

Bark mulch looks promising as a barrier against slugs and snails, yet its success hinges on texture and timing. Fresh, chunky chips form a dry, sharp-edged carpet that grazes soft bodies and steals moisture from their slime, so nocturnal marauders often skirt around in search of smoother ground. Spread five centimetres at dusk and you may wake to lettuce untouched and only silvery trails veering elsewhere.

However, the shield weakens once rain soaks the layer. Damp bark offers crevices that harbour the very pests you hoped to deter, providing cool daytime refuge and hidden highways beneath the surface. Fungi soon soften edges, reducing abrasion, while fallen leaves create bridges. The mulch thus turns from obstacle to hideout unless managed. Lift pots for inspection, rake the top centimetre regularly, and replace sodden, decayed pieces each spring. Adding crushed eggshells or coarse grit along planting rows stiffens the gauntlet further.

AHS LTD recommends combining fresh bark with wildlife-friendly traps rather than relying on any single tactic. Encourage frogs, beetles and hedgehogs, and the mulch becomes one element in a layered defence, slowing the advance of slugs and snails without resorting to pellets that upset garden balance or harm soil-dwelling allies, insects too.