Depending on the variety, potatoes take from 80 to 120 days to mature. As a “rule-of-thumb,” I suggest 100 days to start digging from the date of planting. If you like “new” potatoes, you can try digging early to check their size and maturity. At the time the plant blooms, there will be small edible tubers present, but the full crop potential of the plant is still several weeks away.