If you haven’t started saving eggshells yet get crackin’. Your tomato plants will love you for it. I save eggshells all year round. Not only for our Nitty Gritty soap (an after the garden best friend) but for our tomato plants as well. They love the calcium that the ground eggshells provide. Just rinse the shells with warm water set on a paper towel to dry. When it’s time to plant put the shells right down in the ground with your tomato plant. 
But don’t stop there! Keep saving because you can put all the extra shells in empty milk jugs, fill with water and water your plants with a natural calcuim rich fertilizer. 
Have a problem with slugs around your lettuce? Sprinkle your ground eggshells on top the ground around the lettuce plants! Problem solved!
Dig in and have fun!