When to Harvest Potatoes (5 Signs They're Ready)

Potatoes tell you when they're ready by what's happening above ground. Once the tubers finish forming, the leaves stop being useful to the plant and start to die off. Look for foliage that's lost its bright green color and is shifting toward yellow, brown, and limp. The stems will start to lay over instead of standing upright.

If a plant is still vivid green with leaves pointing skyward, those potatoes underneath are still bulking up. Leave them alone. The signal you want is unmistakable: the top of the plant looks like it's giving up.

Not every plant in the same bed will be ready at the same moment. Some will show early wear - a few yellow spots on the lower leaves, slight discoloration on the edges - but the stems are still standing tall. That plant has another week or two underground.

Mark it mentally, water the rest of the bed normally, and check again in seven days. Pulling early gives you small potatoes with thin skins that won't store. The patience pays off in pounds.

If you're still unsure, dig one plant to check before you commit to the whole bed. Use a hand trowel and start about 8 inches out from the main stem so you don't slice into any tubers. Lift one potato and rub the skin with your thumb.

If the skin scrapes off easily, the crop isn't fully cured underground yet and needs another week or two. If the skin stays put and feels papery-firm, the rest of the bed is ready to come up.

Once most plants have laid over and browned, stop watering. Letting the soil dry out for a week or two firms up the skins, reduces rot risk, and makes lifting cleaner. The plants are done feeding the tubers anyway - extra water at this stage just feeds rot.

Pick a stretch of dry weather for the actual dig if you can. Harvesting wet potatoes from wet soil leads to bruises, mud caked on every tuber, and a much shorter storage life.

Slide a garden fork into the soil about a foot away from the stem and rock it backward to break up the root ball, then lift straight up. The whole plant comes out with the bulk of the tubers attached. For container or whiskey-barrel plantings, you can often grab the dead stem and pull the whole plant out by hand without a tool at all.

Work slowly. Spear damage from a fork driven too close to the stem is the most common harvest mistake, and a punctured potato won't store more than a few days. Better to lift one extra forkful of soil than slice through your biggest potato.

After lifting the main plant, get down on your knees and feel through the loose soil with your hands. Tubers grow on stolons that snap off easily when you pull the plant, and the stragglers left behind are usually the biggest potatoes of the crop.

Sweep down at least 6 inches and out a foot in every direction from where the stem was. Missing the stragglers means a volunteer plant next spring and a smaller harvest right now. Two minutes of digging through dirt with bare hands is worth several pounds of potatoes.

Do not wash freshly dug potatoes. Water dramatically shortens their storage life. Instead, brush off loose dirt with a dry soft brush or your hand and lay the potatoes in a single layer on newspaper or burlap.

Keep them in a cool, dark, well-ventilated spot at around 50 to 60 degrees for 10 to 14 days. Curing thickens the skin, heals small scrapes from the fork, and is the single biggest factor in whether your potatoes last a month or six months.

Once cured, sort the harvest. Set aside any potatoes that are bruised, green-tinged, or damaged from the fork to use this week - they will not store. Store the rest in a paper sack, burlap bag, or wood crate in a cool dark spot around 45 to 55 degrees.

Skip plastic bags and skip the fridge. Plastic traps moisture and the cold temperatures of a refrigerator turn potato starches into sugar, ruining the texture. Check the stash every few weeks and pull anything that softens. Stored well, your potatoes will keep for four to six months.