Harvest guide
When to Harvest Potatoes (Signs They're Ready)
Dig new potatoes around flowering, about 6 to 8 weeks after planting. Wait for maincrop potatoes until the tops die back and the skin sets, roughly 90 to 120 days.
Days to maturity
70–120days
Ready when
New: at flowering. Maincrop: 2-3 weeks after foliage dies back
The short answer
Dig new potatoes at flowering, about 6 to 8 weeks after planting, when the skins are still thin. Leave maincrop potatoes until the tops yellow and die back, roughly 90 to 120 days, then wait about 2 weeks more so the skin sets. Stop watering once the tops die and dig on a dry day.
Days to maturity by potato type
The right harvest day depends on the type you planted. Early varieties race to small tubers. Maincrop types take their time and pay you back with storage.
The numbers below come from US extension guidance. Treat them as ranges, since soil, weather, and variety all shift the date.
| Type | Days to maturity | Harvest cue |
|---|---|---|
| New / first early | 60–80 | At flowering, skins still thin |
| Second early | 80–100 | Tops starting to yellow |
| Maincrop / storage | 90–120 | Tops fully died back, then wait ~2 weeks |
University of Maryland Extension puts maincrop potatoes at 100 to 120 days. Clemson and others land in the same 90 to 120 day band.
New potatoes are the exception. You can dig those 6 to 8 weeks in, once the plants flower, long before the rest of the season plays out.
How to tell potatoes are ready
The plant tells you when. You read the foliage first, then check the skin with your thumb.
Here is what each sign means:
- Flowers open. That signals new potatoes are forming under the soil. Dig a test plant for tender new potatoes, or leave them to size up.
- Tops yellow and die back. The vines flop, brown, and dry out. That is the maincrop signal that tubers have stopped growing.
- Skin is set. Rub a tuber with your thumb. If the skin holds and won't scuff off, it is storage-ready. If it peels, the potatoes need longer in the ground.
For storage, give the crop about 2 weeks in the soil after the tops die back. That window is what sets the skin and toughens it for the cellar.
Pro tip
Stop watering once the tops start to die back. Dry soil firms the skin and makes for a cleaner dig. Then harvest on a dry day, since wet tubers bruise and rot faster than dry ones.
How to dig without spearing them
The tubers sit wider than the plant looks, so the trick is to start your fork well outside the stem. A speared potato won't store and has to be eaten right away.
Work through it like this:
- Push a garden fork into the soil about 8 to 12 inches out from the base of the plant.
- Rock the fork back to lift the whole clump, soil and all, rather than stabbing straight down at the center.
- Lift gently and sift the loosened soil with your hands to find strays.
- Run your fingers through the hole again, since the biggest tubers often sit deepest.
A spading fork beats a shovel here. The tines slide past tubers where a blade slices them. University of Maryland Extension recommends a spade fork for the same reason.
Leave the dug potatoes out of direct sun. An hour or two to dry is fine, but longer turns the skin green.
Common mistake
Three ways a good crop goes to waste. Digging too early, before the skin sets, gives you tubers that bruise and rot in weeks instead of months. Eating green or sprouted potatoes, which build up a bitter compound that can make you sick, so cut away any green and toss heavily sprouted ones. Storing them wet, which traps moisture against the skin and invites rot. Brush off the soil and keep them dry.
Curing and storing your harvest
Curing is the step that turns a harvest into a winter's worth of potatoes. It heals the nicks from digging and thickens the skin.
Spread the potatoes in a single layer somewhere dark and airy. Hold them at about 50 to 60°F for 10 to 14 days, the range Clemson gives for storage potatoes.
After curing, move them to long-term storage:
- Cool and dark. Aim for 40 to 50°F with moist air around 90 percent humidity. A basement or root cellar works.
- No washing. Brush off dry soil and store them dirty. Water shortens their life.
- Not the fridge. Cold below 40°F turns potato starch to sugar, which makes them sweet and discolored when cooked.
- Out of light. Light greens the skin, so keep them in the dark or in a paper sack.
Done right, cured maincrop potatoes keep for 6 to 8 months. New potatoes don't cure or store, so eat those within a week.
Your next step
New potatoes come at flowering, around 6 to 8 weeks. Maincrop waits for the tops to die back, then about 2 weeks more, near the 90 to 120 day mark. Cure them, store them cool and dark, and skip the wash.
Planning next year's bed already? Spacing drives the size and number of tubers you'll dig, so set your rows with the Plant Spacing Calculator, and feed the bed first with how much compost do I need. For the rest of the harvest, see when to harvest onions and when to harvest carrots.
How many plants fit your bed
When you replant, size the bed first. Run your dimensions through the calculator to see how many plants fit in square, triangular, and square-foot layouts.
Try it — Plant Spacing Calculator
Full calculatorExtra to cover losses (10% is typical).
You can plant
32plants
- Per row
- 8
- Rows
- 4
- Buy (incl. spare)
- 36 plants
Common questions
How long after flowering can you harvest potatoes?
Flowering is the cue for new potatoes, not maincrop. Once the plants bloom, usually 6 to 8 weeks after planting, you can dig small new potatoes. For full-size storage potatoes, leave them in the ground until the tops die back, then wait about another 2 weeks before digging.
Can you harvest potatoes too early?
Yes. Dig before the skins set and the tubers stay small, bruise easily, and won't keep. New potatoes are fine eaten fresh within a few days, but anything you want to store needs a set skin that doesn't rub off under your thumb. For storage, wait until the foliage has died back.
How do you cure potatoes after harvest?
Spread the dug potatoes in a single layer in a dark, well-ventilated spot at about 50 to 60°F for 10 to 14 days. Curing lets nicks heal and the skin toughen, which is what makes them store. Don't wash them first and keep them out of the light.
How long do potatoes store?
Cured maincrop potatoes keep for 6 to 8 months in dark, cool, moist conditions, about 40 to 50°F at 90 percent humidity. New potatoes have thin skins and dry out fast, so eat those within a week or so.
Should you wash potatoes before storing them?
No. Brush off loose soil and leave them dry. Washing adds moisture that invites rot and shortens storage life. Save the rinse for the day you cook them.
Sources
Agronomic claims in this guide are checked against these primary sources.
- Growing potatoes in home gardens — University of Minnesota Extension
- Growing Potatoes in a Home Garden — University of Maryland Extension
- Potato — Clemson Cooperative Extension HGIC
- Potato Harvest and Handling — Utah State University Extension
Keep reading
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Read →When to Harvest Carrots (Signs They're Ready)
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Read →When to Harvest Sweet Potatoes (Signs They're Ready)
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