have to do with this picture?
The answer is that these eggshells helped to create a series of heirloom tomatoes this summer (my Italian Sweets to be exact) that did NOT develop blossom end rot (BER). I got this idea from Daphne's blog, but learned it too close to planting time to have collected any eggshells. That is why I am bringing it up now. Once you have a few dozen, wait until a time when you are preheating the oven for some other reason. Lay the shells out on foil or parchment and bake for about 10 minutes at something over 300 degrees. Don't let them burn. The purpose for this is to kill any salmonella. The next step is to place the shells in your food processor and give them a good pulverizing. One word of caution, over time you will dull the inside of your plastic food processing bowl. 
Then I find an old container ... and mark it with a marker CRUSHED EGGSHELLS ... and pour my shells into it. 
The two of us did not consume enough eggs last year to fully plant out my tomato plants with the recommended one cup amendment of eggshells. But I was sure to use them on those that a prone to BER, and was very pleased with the results.
