Diagnosis
Diagnose: Watermelon Blossom End Rot
Use these observations to decide what to check next.
Confirm the blossom scar, then inspect the root zone
Turn the melon without twisting its stem.
A leathery lesion centered on the blossom scar supports blossom-end rot, while damage on the belly where the rind touches wet soil points elsewhere. The symptom does not prove that garden soil lacks calcium, and an amendment is justified only when a soil test identifies the shortage or a pH problem.