Potatoes may be ready to harvest between late June and September, depending on the variety. For instance, new potatoes can be harvested as early as 8.5 weeks after planting.
Most potatoes are grown from seed potatoes or pieces of seed potatoes with two or more eyes on them. These tubers quickly sprout above and below ground. Farmers may harvest their potatoes anywhere between 8.5 weeks to 20 weeks after planting.
Early varieties of potatoes are harvested when the plant growth is still green, healthy and has just sprouted flowers. Gardeners may carefully dig down to the root system and feel for small, new potatoes. These do not last long in storage, so gardeners should only dig up a few at a time to eat.
Potatoes can be continually harvested from this point on. The main crop varieties are harvested between 18 to 20 weeks, as late as the end of September. Main crop potatoes are preferred for long-term winter storage.
When harvesting the main crop, break off the green growth about 2 weeks beforehand to stop growth. Gardeners may also simply wait until the green growth dies and dries up before harvesting. On a nice, dry day, gently dig up the potatoes. Take care not to damage the tuber skins with the gardening implements.