Q What are growth cracks on potatoes?
A When the tubers have deep cracks that have healed over with a rough, callus-like covering, this is a sign that the tuber has grown very fast when wet weather followed dry. In these conditions, the tubers stop growing, then have a spurt of growth when it rains. Viruses can occasionally cause cracks as well, but soil-moisture changes are the main cause. This problem makes the tubers harder to clean or peel, but they are perfectly edible.

Caption: Growth cracks occur when tubers grow very fast when wet weather follows dry

Q What can I do about growth cracks on potatoes?
A Try not to let potatoes dry out completely. Water heavily in dry periods, especially if your soil is prone to drying out. Adding organic matter may help your soil hold moisture, but watering is the only sure way to limit growth cracks