To start, when you crack open your eggs to cook, try to crack them as close to the narrow end as possible. By doing so, you can leave most of the eggshell intact, forming a little cup.
Empty and rinse out the egg with hot water, setting it to dry in a place where the kids (and the cats!) won't be able to knock them off. I usually keep my eggshells in the original cardboard containers.
When you have at least a dozen or so, you have the start of your magickal garden! These eggshells make great miniature planters for starting seeds in. The eggshell symbols new birth and growth, and when the seedlings are large enough, they can be planted in the ground, eggshell and all.
When you do plant them, roll the shell gently between your palms to crack it, so the roots will be able to work their way through.
By starting the seeds in their own little "egg pots," you can charge them in groups for specific purposes, or just provide them with general blessings.
Found at OakDancer.com