Slugs can be one of the most frustrating garden pests, particularly when you’re trying to grow fruits and vegetables. They thrive in cool, damp conditions and are especially active after rainfall, when the soil and surrounding plants provide the moisture they need to move around easily. This can make wet spells particularly worrying for gardeners.
Rather than reaching for chemical slug killers, there are several inexpensive household ingredients that can make the garden less inviting. Sophie Harris, Senior Audience Writer for Spare Time, uses three natural deterrents every year, but one has worked consistently better than the others, particularly for protecting her fruit after rain.
Coffee grounds as a barrier
Coffee grounds were the first deterrent Harris used, as they also have several benefits for the garden. The idea is to scatter used coffee grounds around plants that you want to protect, creating a barrier between the plant and the surrounding soil.
Coffee grounds are often recommended as a slug deterrent because of their texture and caffeine content, but their effectiveness can vary depending on how they are used. Harris sprinkles a layer of used, cooled coffee grounds around the base of vulnerable plants, taking care not to layer it too thickly. She finds they are most useful as part of a wider approach rather than something to rely on exclusively.
Garlic spray and eggshells
Instead of creating a physical barrier, garlic is used to make the plants less appealing to slugs. The strong-smelling compounds in garlic act as a deterrent. Harris makes a simple garlic spray by crushing garlic cloves, steeping them in water and straining the mixture before putting it into a spray bottle.
She then applies it around the plants and on suitable plant surfaces, being careful not to spray any foliage or flowers. The biggest advantage is that it’s easy to apply, whereas creating a physical barrier can be tricky, and it is also easier to refresh after rainfall. However, she didn’t particularly enjoy the smell, and her garden was starting to smell purely of garlic, so she tends to use this only if she has leftover garlic cloves.
Eggshells are a clear winner for protecting her fruit, and the method is incredibly simple. After using eggs, she rinses the shells, allows them to dry and slightly crushes them into small, sharp pieces. She scatters these around the plants she wants to protect, creating a rough layer across the soil surface. Harris uses lots of eggs, so this helps to prevent waste and creates a surface that slugs find unappealing. She found eggshells particularly helpful during a week of rainfall, when slugs had been active in her garden.
