Yes, crushed eggshells can act as a deterrent to snails and slugs in gardens.
Here's why and how they work:
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Sharp Edges: The primary reason eggshells are effective is their sharp edges. When snails and slugs try to cross a barrier of crushed eggshells, the sharp fragments irritate their soft bodies. This discomfort discourages them from proceeding further. The reference notes, "...by sprinkling some of these sharp eggshells underneath they're not sharp to us but they are to slugs."
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Dehydration: The porous nature of eggshells can also contribute to their effectiveness. As slugs and snails move over the shells, the shells can absorb moisture from their bodies, leading to dehydration, further deterring them.
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Calcium Source (Bonus): While the deterring effect is the main benefit, as eggshells decompose, they also release calcium into the soil, which can be beneficial for certain plants, like tomatoes and peppers.
How to Use Eggshells to Deter Snails:
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Collect and Clean: Save your eggshells after cooking. Rinse them to remove any residual egg.
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Dry Thoroughly: Allow the eggshells to dry completely. This prevents mold growth.
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Crush the Shells: Crush the dried eggshells into small, sharp fragments. A food processor or blender can speed up this process, but isn't necessary.
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Create a Barrier: Sprinkle a generous layer of the crushed eggshells around the plants you want to protect. The barrier should be wide enough to discourage the snails from simply crawling over it.
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Reapply Regularly: Eggshells decompose over time and can be washed away by rain. Reapply the barrier every few weeks, or after heavy rainfall, to maintain its effectiveness.
While eggshells can be a helpful deterrent, they may not be a foolproof solution for heavy snail and slug infestations. You may need to combine them with other pest control methods for the best results.
