How To Make Powdered Eggshells. The supplement couldn’t be easier to make. Add the eggshells and cook for 2 minutes.
While they boil, preheat your oven to 200 degrees fahrenheit. Save the extra powdered shells to make more eggshell fertilizer. Bake eggshells at a low temperature in the oven for 10 minutes or so to dry them out.
Strain, spread them on a baking pan or two, and leave them to dry overnight.
Drain the eggshells and place them on a baking tray and allow to dry all day or overnight. You can also use a blender for this, but i find that a coffee grinder makes the finest powder, so you don’t have any large eggshell pieces in. Scoop off any white foam that forms. • spread the eggshells evenly on a baking sheet and bake for 5 to 7 minutes.