Can You Compost Eggshells?
Yes, eggshells are excellent for compost. They add calcium carbonate, which benefits soil and plants. Crush or grind shells for faster decomposition - whole shells can take years to break down. Rinse shells to remove residue, but do not worry about removing the membrane, which also composts.
Key Takeaways
- Eggshells are composed primarily of calcium carbonate, the same compound in limestone and garden lime.
- Cooked and raw eggshells compost equally well.
- Eggshells from hard-boiled eggs may have a slight sulfur smell initially but this dissipates.
Explanation
Eggshells are composed primarily of calcium carbonate, the same compound in limestone and garden lime. Adding them to compost contributes calcium, which plants need for cell wall strength, disease resistance, and proper growth. It can also help balance acidic compost.
Crushing shells speeds decomposition significantly. Whole shells are very slow to break down and may still be visible in finished compost. Crushing by hand is adequate; grinding in a blender or coffee grinder creates a powder that decomposes fastest and is easiest for plants to use.
Eggshells can go directly into garden soil as well as compost. Crushed shells around plants are sometimes used to deter slugs (though effectiveness is debated). In acidic soils, eggshells provide slow-release calcium over time.
Things to Know
- Cooked and raw eggshells compost equally well.
- Eggshells from hard-boiled eggs may have a slight sulfur smell initially but this dissipates.
- Adding too many eggshells without balancing other materials can slow decomposition.