Sher Miller wrote:I agree that giving eggshells back to chickens is a good idea. They don't have very big brains, so the shell only needs to be broken a little so they don't recognize them as eggs. Lack of calcium is a major reason why they would eat their own eggs.
I use my eggshells on plants (and sometimes in animal water) as Water-Soluble Calcium (WCa). In Korean Natural Farming (KNF), it is generally given as part of a dilute formula, depending on the plant's life stage, and for conditions such as blossom end rot.
The shells need to have all membranes removed. I have recently come across "phoenix skin?" where the membranes are used for skin treatment/care. I haven't looked into that yet. Please share if you know about it. Anyway, if the membranes are not fully removed, they will add gick to the solution, and it will degrade and get nasty.
The shells need to be slightly toasted (to a light brown) to chemically alter the calcium. This is also true if you make this with another source of calcium carbonate, like oyster shells.
Keep the shell pieces rather large. Add fermented vinegar (distilled vinegar is used as an herbicide) in a ratio of 1 part shells to 10 parts vinegar. The shells will start to bubble.
Once the bubbles stop, the vinegar is saturated with calcium. Decant and spray on plants diluted 1:1000. You can add more vinegar to the shells and keep doing this until the shells are gone.