Mulch
Using eggshells for mulching your garden is an inexpensive and effective way to feed your plants. One more advantage is that eggshells look like pebbles from far away, and they can act as decorative elements if you spread them on your pots.
After finishing a hearty breakfast or baking a yummy cake, crush up your eggshells and put them in your garden! As they slowly begin to decompose, they’ll not only help to aerate the soil as they improve water flow, but they’ll also release calcium over time.
Just remember that the finer you crush them, the faster they’ll start breaking down.