Blossom end rot happens when a plant can’t move calcium to developing fruit — even when calcium is already present in the soil.
The most common cause is inconsistent watering, especially during hot or fast growth periods.
Adding eggshells or calcium products won’t fix the problem if water uptake is irregular.
Grow smarter:
Water deeply, consistently, and avoid letting soil swing between dry and soaked.
Containers are more prone to blossom end rot because they dry out faster.