Oklahoma · zones 6b–7b
When to plant potatoes in Oklahoma.
Sow between Feb 20 to Mar 25 in a typical year, keyed to Oklahoma's median last frost around Mar 30. A second, fall sowing fits Jul 17 to Jul 30. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Potatoes dates for a typical Oklahoma season.
Direct sow
Feb 20 to Mar 25
Keyed to the ~Mar 30 last frost. Sow 4" deep, 12" apart.
Fall round
Jul 17 to Jul 30
Counted back from the ~Nov 4 first frost.
Harvest
~90 days later
~3 lb per plant over ~1 weeks.
Oklahoma spans more than one climate: Zone 7 is the most common zone, but the state runs 6b to 7b. 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.
Oklahoma growing notes
Oklahoma potatoes have to finish before the heat locks them out.
Red clay wants a raised hill, not a trench
Much of Oklahoma gardens sit on red clay, heavy ground colored by iron oxide that holds water in spring and bakes into something close to brick by midsummer. Potatoes size their tubers in loose ground, and clay resists that; the squeeze test tells you what you are working with: grab a handful of moist soil, and if it forms a ribbon longer than 2 inches before breaking, build raised hills rather than planting in a flat bed or trench.
Work 3 to 4 inches of compost or coarse sand into the top of a hill before seed pieces go in 4 inches deep, spaced 12 inches apart down the row. Loosened, raised ground drains the hard spring rains Oklahoma gets before summer heat sets in, and drained ground is exactly what keeps seed pieces from rotting before they ever sprout.
Tuber set has a heat ceiling around 85 degrees
Potato plants stop forming new tubers once soil temperature at root depth holds above roughly 85 degrees for an extended stretch, and Oklahoma's short run from last frost to real summer heat means that ceiling arrives fast. Choose an early-maturing type that reaches harvest size in about 90 days without stalling, and get seed pieces in as soon as the soil has warmed enough to sprout them rather than waiting on a fixed date.
Pull red dirt up against the stems every couple of weeks until the mound stands roughly half a foot proud of the row. That mound does double duty here: it buries developing tubers so they cannot green in the sun, and the extra soil mass keeps the root zone a few degrees cooler than bare, exposed ground on a 100 degree afternoon. A 3 to 4 inch layer of straw mulch over the hill adds another few degrees of insulation on top of that.
Colorado potato beetle and early blight, watched weekly
Colorado potato beetle overwinters in Oklahoma soil and finds new potato plants fast in spring; turn leaves over as you walk the rows and scrape the orange egg clusters off into soapy water before they hatch. Once striped grubs are chewing, sample ten plants and average them; more than a couple of larvae per plant on that average justifies a targeted spray, because a heavy hatch can strip a young plant's leaves within days and cut yield hard.
Early blight, not the late blight that gets more attention in gardening guides, is the disease actually worth watching in an Oklahoma summer: late blight needs a sustained run of cool, humid weather to spread, and its progression halts once daytime temperatures push into the mid-90s, a ceiling Oklahoma's summer blows through for weeks on end. Early blight announces itself with concentric rings inside each dark spot, starting low on the plant, on the oldest leaves, and climbing upward as the weeks pass. There is no cure once it takes hold, only stripping the infected foliage to slow the spread to the rest of the row, so walk the row every few days through a humid stretch rather than waiting for a symptom to become obvious from a distance.
In Oklahoma: watch for
The pests that find potatoes here.
A middle-length season, about 219 frost-free days, means potato overlaps colorado potato beetle for a stretch each summer. Check plants every week or two and treat early.
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: Oklahoma gives potatoes about 219 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 Oklahoma: questions
When should I plant potatoes in Oklahoma?+
In a typical Oklahoma year, sow potatoes between Feb 20 to Mar 25, keyed to the state's median last frost around Mar 30. There's also a fall window: Jul 17 to Jul 30. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is Oklahoma?+
Oklahoma spans zones 6b–7b, mostly zone 7. 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.