3. Add Them to a Worm Bin
Finely powdered eggshells can also be useful in vermicomposting systems.
Small amounts provide mineral grit that worms can use during digestion.
The key word is finely.
Large, sharp shell pieces aren’t nearly as useful as thoroughly crushed or powdered shells.
Sprinkle small amounts periodically rather than dumping a large quantity into one location.
4. Use Them When Preparing New Garden Beds
If you’re creating a new vegetable bed or refreshing existing soil, finely ground eggshells can be mixed with compost and other organic amendments.
They’re particularly appropriate when a soil test indicates that additional calcium is needed.
Remember that eggshells can also influence soil chemistry over time because calcium carbonate has a liming effect.
For that reason, more isn’t automatically better.
5. Save Them for Tomato and Pepper Beds—But Know Their Limitations
Eggshells are frequently recommended for tomatoes and peppers because calcium deficiency is associated with blossom-end rot.
