One of the fertilizers we use in our vegetable garden is egg shell. My mother would crush it with her hands and sprinkle it around the plants. But thanks to internet because I learned another method to use egg shell fertilizer, the egg shell water!
We never run out of eggs. Every morning, we eat eggs that's why grinding egg shells has almost become a routine for me every afternoon. First, I wash the egg shells to remove the slimy egg white before drying them under the sun. (Removing the egg white helps the egg shells to dry faster and make the shells really dry so it is easier to grind.)
Second, when the shells are dried, I grind them with a mortar and pestle until the texture becomes almost powder-like.
Third, I add a couple of scoops of grinded egg shell into a 6-Liter bottle and let it sit for one day before using it to water the plants. The water should get cloudy especially when you shake the container.
I've been doing this for almost two weeks now and I think the plants like it. The egg shell is rich in calcium which is needed by plants. You can reuse the powdered egg shells in the bottle a couple of times and only replace it when the unpleasant smell is gone. :)