Maturity Sings of Sweet Potato:
1. They are harvested 3.5 to 4 months after planting.
2. Leaves start yellowing
3. After cutting the tuber if white gum remains white, then they are ready for harvest , it it turns blackish on green then tubers are said to be immature.
Harvesting of Sweet Potato:
The crop is harvested by digging with spade or kudali.
Source : agriinfo