1. Soil Amendment: Eggshell powder is rich in calcium carbonate, which makes it a valuable soil amendment. It can be used to raise soil pH in acidic soils, thereby making it more suitable for plant growth. Additionally, the calcium in eggshell powder helps improve soil structure and nutrient availability.

2. Fertilizer: Eggshell powder contains other essential nutrients like potassium, magnesium, and phosphorus, albeit in smaller amounts. When ground into a fine powder, it can be used as a slow-release fertilizer, providing these nutrients to plants over an extended period.

3. Compost Enhancer: Adding eggshell powder to compost piles can accelerate the decomposition process and improve the quality of the resulting compost. It contributes additional calcium to the compost, which benefits the plants when the compost is applied to the soil.

4. Seed Starting: Finely ground eggshell powder can be sprinkled on top of the soil while starting seeds. It provides a slow-release calcium source for the young seedlings, aiding in their early development.

5. Vermicomposting: Eggshell powder can be used as a component in vermicomposting, a process where earthworms decompose organic matter into nutrient-rich castings. The calcium and other minerals in eggshell powder add value to the vermicompost produced.