Eggshell calcium powder
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Rinsed and dried eggshells ground fine to add calcium to garden soil and around tomatoes.
What You’ll Need
- Eggshells rinsed
- Mortar and pestle or coffee grinder
- Airtight container
- Optional: oven, for sterilizing
Equipment
- spice grinder
- airtight jar
Directions
- Rinse the shells well.
- Set them on a sunny windowsill to dry.
- If you like, sterilize them in a 200°F (93°C) oven for 30 minutes. This matters for powder that you or your dogs might eat, and is optional for garden use.
- Crush the shells with a mortar and pestle, or grind them in a coffee grinder.
- Keep the powder in an airtight container.
Notes
Work a handful into tomato planting sites, or one or two handfuls (about 1/4 cup) per tomato or pepper planting hole; sprinkle a generous handful around plants from time to time; dig into soil or add to compost. Eggshell water: steep dried shells a couple of days, strain, and water plants (including houseplants).
Caveats : shells are mostly calcium and release it very slowly, so you need a lot to make a measurable difference. Myth: shells on the soil surface do not deter slugs (Oregon tests found a ring of shells increased slug feeding). Don’t bury whole eggs in pots.
Safety: Raw shells can carry salmonella; wash hands after handling and dry or bake them before grinding. Use a grinder kept for garden use, or clean it well. Wear a dust mask when grinding (fine dust).