Gardeners are being encouraged to place crushed eggshells around vulnerable plants this month as a natural, wildlife-friendly method to deter slugs and snails. These common garden pests can destroy vegetable crops and ripening strawberries in a matter of hours, leaving plants reduced to stems and harvests ruined.
Why Eggshells Work Against Slugs
Slugs and snails are averse to crawling over the sharp, jagged edges of crushed eggshells. When scattered around the base of susceptible plants like salad leaves, courgettes, peas, and strawberries, the shells form a physical barrier that the molluscs avoid. Some gardeners have reported success by leaving eggshells in halves, creating a substantial sharp-edged barrier around each plant.
However, the Royal Horticultural Society (RHS) notes that after rainfall, eggshells can become slippery and less effective. Despite this limitation, the method remains a popular organic option for protecting homegrown produce.
Natural Alternatives Recommended by the RHS
On its website, the RHS suggests other natural traps: "Traps, such as scooped-out half orange, grapefruit, or melon skins, can be laid out cut side down or jars part-filled with beer and sunk into the soil near vulnerable plants. Check and empty these regularly, preferably every morning." These traps lure slugs and snails away from edible crops, allowing vegetables and strawberries to thrive.
Another biological control option is 'Nemaslug', an organic product containing microscopic nematodes (worms) that are watered into the soil. These nematodes enter the slugs' bodies and infect them with bacteria that cause a fatal disease, posing no danger to other wildlife.
Expert Warnings on Slug Pellets
While slugs play an important role in the ecosystem as food for birds and other wildlife, gardens can become overrun, causing significant damage. Experts caution that slug pellets, including organic varieties, can harm beneficial garden wildlife. The eggshell method and other natural alternatives offer a safer approach to managing slug populations without collateral damage.
For best results, gardeners should apply crushed eggshells after rain or watering, and combine methods such as traps and biological controls for comprehensive protection throughout the growing season.
