Hawaii · zones 12a–12a
When to plant potatoes in Hawaii.
Sow between Nov 24 to Dec 27 in a typical year, keyed to Hawaii's median last frost around Jan 1. A second, fall sowing fits Sep 12 to Sep 25. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Potatoes dates for a typical Hawaii season.
Direct sow
Nov 24 to Dec 27
Keyed to the ~Jan 1 last frost. Sow 4" deep, 12" apart.
Fall round
Sep 12 to Sep 25
Counted back from the ~Dec 31 first frost.
Harvest
~90 days later
~3 lb per plant over ~1 weeks.
Hawaii spans more than one climate: Zone 12 is the most common zone, but the state runs 12a to 12a. 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.
Hawaii growing notes
True potato here is a nightshade grown from a buried seed piece, and it is common scab, not blight alone, that shows up first if the ground dries out while tubers are setting.
A different plant wearing a similar name
True potato and sweet potato share an English name and little else. One is a nightshade grown from a cut seed piece, the other a morning glory grown from a rooted cutting, and the split runs down to what threatens each: late blight, the most serious disease either crop faces here, has no interest in a sweet potato vine, and the reverse holds too. A grower running both crops in the same yard needs two separate habits of watching, not one shared checklist.
Here the plant goes in direct, seed pieces set about 12 inches apart and a substantial 4 inches deep, deeper than almost anything else planted this way, with a harvest around 90 days out and a solid return for the space, roughly 3 pounds per plant. That depth is a starting point, not a finish; as stems push up, pulling loose soil around the base in one or two passes, called hilling, buries the shallow tubers that would otherwise push into daylight and turn green and bitter from sun exposure. A greened tuber is worth discarding rather than eating, so hilling is doing real work here, not just tidying the row.
Both windows are open, but only one round is worth reading correctly
Potatoes carry an early planting window and a later one here, yet only a single round is scheduled between them, unlike the many-sowing rhythm given to a crop like carrots or lettuce. Tuber formation leans on cooler soil to happen well, and that is a narrower opportunity in a warm lowland yard than the wide-open, plant-anytime pattern a heat-tolerant crop gets. Treat the two windows as two separate, deliberate attempts rather than interchangeable slots, and pick whichever one tends to bring cooler nights or more overcast weather at the actual site.
Because the crop sits out of sight underground for the whole 90 days, waiting for a fixed point on the calendar to check on it is the slow way to learn how a planting is doing. Partway through, ease a hand into the edge of a hill to feel for tuber size without pulling the whole plant; that gives an honest read on progress. A heavy mulch over the hilled rows helps too, keeping the root zone shaded and cooler than bare soil baking in full sun, and keeping that same root zone evenly damp does double duty against a soil-borne problem covered next.
Common scab and late blight pull in opposite directions on moisture
Common scab is the soil-borne problem to watch for on the tubers themselves: rough, corky patches on the skin, raised on some tubers and sunk into shallow pits on others. It looks worse than it is; a scabby tuber is still fine to eat once peeled. The lever here is even soil moisture through the weeks right after tubers set, not the soil's pH, so the fix is practical rather than chemical: keep the hilled rows watered on a steady schedule through that stretch rather than letting the bed swing between dry and soaked.
Late blight works the opposite way, favoring wet leaves rather than dry soil, and it is the one to treat as an emergency. It shows as dark, water-soaked blotches on leaves that expand within days, with a pale, fuzzy mold visible on the underside during humid weather, and it does not stop at the foliage; the same infection can travel down into the tubers and rot them both in the ground and after they are dug. A plant showing this is worth pulling and hauling off, not composting, the same day it is noticed. Aphids close out the picture, clustering on new growth and capable of spreading virus between plants; a firm spray from the hose keeps a small colony from becoming a bigger problem.
In Hawaii: watch for
The pests that find potatoes here.
With about 364 frost-free days, potato spends longer in the ground here than in most of the country, which widens the window in which aphids can find it. Scout weekly from midseason and act on the first signs.
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: Hawaii gives potatoes about 364 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 Hawaii: questions
When should I plant potatoes in Hawaii?+
In a typical Hawaii year, sow potatoes between Nov 24 to Dec 27, keyed to the state's median last frost around Jan 1. There's also a fall window: Sep 12 to Sep 25. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is Hawaii?+
Hawaii spans zones 12a–12a, mostly zone 12. 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.