New Hampshire · zones 4b–6a
When to plant potatoes in New Hampshire.
Sow between Apr 7 to May 10 in a typical year, keyed to New Hampshire's median last frost around May 15. A second, fall sowing fits Jun 10 to Jun 23. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Potatoes dates for a typical New Hampshire season.
Direct sow
Apr 7 to May 10
Keyed to the ~May 15 last frost. Sow 4" deep, 12" apart.
Fall round
Jun 10 to Jun 23
Counted back from the ~Sep 28 first frost.
Harvest
~90 days later
~3 lb per plant over ~1 weeks.
New Hampshire spans more than one climate: Zone 5 is the most common zone, but the state runs 4b to 6a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
New Hampshire growing notes
Rocky ground makes New Hampshire potatoes a shape problem first.
A 90-day potato in a tight New England season leaves little slack
New Hampshire's growing season averages about 136 frost-free days state-wide, the shortest average of the three northern New England states, but a North Country or hill-valley garden regularly falls several weeks under that number, which means a 90-day potato variety leaves less room for a slow start or a rough patch of weather than gardeners moving here from almost anywhere else might expect. Early varieties bred for short seasons help close that gap: Dark Red Norland gives a reliable red-skinned option, and Superior, a buff-skinned white chipper bred at the University of Wisconsin, is the pick if you want white rather than red. Superior needs a genuine 80 to 90 days rather than the 70 sometimes claimed for it, and Dark Red Norland runs in that same early range; both still dig weeks ahead of a full-season Kennebec or Russet and give this state's growers real breathing room.
Sprouting seed potatoes indoors 2 to 3 weeks before planting, a practice called chitting, gets a jump on that tight calendar without risking cold soil rot; short, stubby green sprouts an inch long are the goal, not the long pale ones that come from a dark cupboard. Plants that go into the ground already sprouted emerge faster and give the crop back some of the days a short season otherwise takes away from it.
Rocky till means the shape of your potatoes, not just the yield
New Hampshire's glacial till soil is famous for stones, and gardeners here know the frustration of a fork turning up potatoes bent, forked, or split around a rock the tuber had to grow past on its way down. Beyond the cosmetic problem, rocky ground also compacts hilling soil unevenly, leaving gaps where sunlight reaches developing tubers and turns them green. A raised bed filled with rock-picked, amended soil sidesteps the whole issue for a home planting far more reliably than hand-picking stones out of native ground each spring.
The state's acidic native soil, unusual as a plus in gardening, actually works in a potato grower's favor here: common scab, the disease that pits tuber skin with rough patches, needs a real drop to pH 5.2 or below before suppression becomes reliable, and New Hampshire ground often sits at or under that mark without any amendment at all. Resist the urge to lime a potato bed the way you would for most other vegetables; here, leaving the soil alone is the correct move to make.
Late blight moves fast through a foggy hill valley
Late blight thrives on exactly the weather New Hampshire's hill-and-valley terrain produces regularly: a cool, humid stretch where fog settles into low ground overnight and burns off slowly the next morning. Watch for water-soaked, dark blotches spreading across leaves within days of a foggy run of mornings, since this disease moves faster than almost anything else that hits a home garden and can take a full row from healthy to collapsed within a week under the right conditions for it.
There is no treating an infected plant, only removing it, bagged rather than composted, to keep spores from riding the wind to the next row or the neighbor's garden nearby. Once vines die back on their own near the end of the season, resist digging right away; give the skins a full 2 weeks to toughen underground first, since thin-skinned potatoes dug too early bruise in storage and rot within weeks instead of holding through winter.
In New Hampshire: watch for
The pests that find potatoes here.
The short season here, about 136 frost-free days, keeps potato in front of colorado potato beetle only briefly. One early row cover usually carries a planting through the worst of it.
Striped beetles and orange grubs eating the leaves.
Organic fix: Handpick adults, crush the orange egg clusters, dust with diatomaceous earth.
Dark greasy blotches after cool, wet spells.
Organic fix: Pull infected plants fast, keep leaves dry, use neem as a preventive.
Common scab
Rough, corky patches on the skin, raised on some tubers and sunk into pits on others.
Organic fix: Keep the bed evenly moist through the weeks right after tubers set, rotate away from potatoes, and pick a scab-resistant variety next time.
Your season math: New Hampshire gives potatoes about 136 frost-free days, and it needs roughly 90 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting potatoes in New Hampshire: questions
When should I plant potatoes in New Hampshire?+
In a typical New Hampshire year, sow potatoes between Apr 7 to May 10, keyed to the state's median last frost around May 15. There's also a fall window: Jun 10 to Jun 23. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is New Hampshire?+
New Hampshire spans zones 4b–6a, mostly zone 5. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many potatoes plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.