I saw an editorial on apartment therapy awhile back about using egg shells as seed starters. What an excellent idea ! Some people compost their egg shells, so we all know they break down well. We don’t need to worry about frost in Northern California at this time, however we still made a decision to plant some seeds indoors and watch them grow. When they‘re able to put inside the garden the egg shell goes into the bottom too !
Every time I made use of an egg I’d rinse the shells and set it aside. Pretty soon we‘d enough to start out a dozen seedlings !