Eggshells take too long to dissolve, even when powdered, to fix this issue quickly. Grab some bonide rot stop or fertilome yield booster which are liquid formulas you can dilute and add to stop end rot. I had this issue with certain varieties of tomato when grown in pots, and I discovered that watering once a day was not enough, and the tomatoes depleted all the nutrition in the soil pretty quickly. I mulch and then water twice a day when it gets above 90f, and add yield booster every few weeks.
Eggshells take too long to dissolve, even when powdered, to fix this issue quickly. Grab some bonide rot stop or fertilome yield booster which are liquid formulas you can dilute and add to stop end rot. I had this issue with certain varieties of tomato when grown in pots, and I discovered that watering once a day was not enough, and the tomatoes depleted all the nutrition in the soil pretty quickly. I mulch and then water twice a day when it gets above 90f, and add yield booster every few weeks.