Unlikely — Zone Mismatch
potato yam (zones 9-12) does not overlap with Ohio's zone range (5b-7a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Potato Yam is hardy to zone 9, and the warmest ground in Ohio is zone 7 — 2 zones short. Planted in open ground it will not survive a Ohio winter. To grow it here, grow potato yam under glass — a greenhouse is the only lift this wide the engine models.
A greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 9-12 (plant) against 5-7 (Ohio). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
Ohio spans zones 5b-7a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score potato yam against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Potato Yam Needs
- USDA Zones: 9-12
- Frost-Free Days: 90+
- Sun: Full Sun
- Picking window: ~30 days of harvest
Ohio Has
- USDA Zones: 5b-7a
- Last Hard Freeze (28°F): Apr 5 - Apr 13
- First Hard Freeze (28°F): Oct 31 - Nov 6
- Annual Rainfall: 34-42 inches
- Common Soils: Glacial till, Clay loam, Silt loam
Plant Zone Range (zones 9-12)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Potato Yam in Ohio
The frost window
Across Ohio, the last spring hard freeze (28°F) clears between Apr 5 and Apr 13, and the first fall hard freeze lands between Oct 31 and Nov 6 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 201-day window you can count on — up to 215 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Winter standing
Ohio runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for potato yam, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether potato yam is a permanent planting or a replant-every-spring crop for you turns on your own zone within Ohio; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Geauga County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says potato yam does not survive a Ohio winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Ohio under protection.
Frost-free days
Potato Yam wants 90+ frost-free days; a typical Ohio site sees ~208 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Potato Yam likes near-neutral soil (pH 5.3-8). That's the common-ground band across Ohio's glacial till and clay loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 6.7 — worth knowing before you decide whether a Ohio soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Ohio site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 28.6% of Ohio as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Potato Yam sits mid-range for drought tolerance, so either extreme can cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Ohio soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Potato Yam in Ohio — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 9-12 (USDA PLANTS Database)
- State Zones: 5b-7a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 5 - Apr 13 to Oct 31 - Nov 6 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Potato Yam in Ohio
Zone compatibility tells you about winter cold survival — but Ohio growers also need to think about:
Heavy clay soils across much of northern Ohio require amendment for drainage
Variable spring weather with late frost risk through mid-May
Japanese beetles and tomato hornworms are common garden pests
Wet springs can delay planting and promote root rot
Growing potato yam here specifically
Potato Yam roots run deep and prefer pH 5.3–8.0, but drainage comes first here: SSURGO maps about 28.6% of Ohio as poorly or somewhat-poorly drained, and wet ground rots its crown before pH ever matters.
Plant potato yam on a raised, gravel-amended berm so water drains fast and the crown stays dry. How to handle it →
What to actually do about these — and the constraints that apply to every Ohio grower, not just potato yam — is covered on the Ohio growing guide.
Timing shifts within Ohio
Ohio isn't one climate. In Geauga County, the last hard freeze (28°F) holds until about Apr 22 — roughly 13 days later than the recorded state median — so plant potato yam to your county's window, not the statewide date.
Potato Yam needs about 90 days of frost-free season to complete its cycle. Even Columbiana County — Ohio’s shortest season at 182 frost-free days — clears that by 92 days, so season length isn’t the constraint anywhere in Ohio. What varies is your own parcel.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Potato Yam's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Potato Yam draws native bees (low value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, potato yam can only work that bloom inside Ohio's frost window — roughly 208 days, opening after the last 28°F freeze (Apr 5 - Apr 13) and closing at the first (Oct 31 - Nov 6), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Potato Yam
Potato Yam is listed as toxic to dogs, cats (all) at a moderate level (Cornell). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
Ohio Cooperative Extension
For Ohio-specific cultivar recommendations, planting calendars, and pest pressure for potato yam, the canonical source is Ohio State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Potato Yam native to Ohio?
No — the USDA PLANTS Database lists Potato Yam as introduced rather than native in the Lower 48, so it is not part of Ohio's native flora. It grows here as a garden plant; pairing it with a few Ohio natives keeps local pollinators fed too.
Looking for plants that belong here? The Ohio growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Potato Yam in Ohio
When can I plant Potato Yam in Ohio?
Ohio's last spring hard freeze (28°F) clears between Apr 5 and Apr 13, and the first fall hard freeze lands between Oct 31 and Nov 6 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Potato Yam, so this page does not state whether it overwinters in Ohio and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Potato Yam grown in across Ohio?
Ohio spans USDA hardiness zones 5b-7a (USDA ARS PHZM 2023). Potato Yam carries a range of zones 9-12, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Ohio site have?
A typical Ohio site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Potato Yam needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Geauga, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Potato Yam native to Ohio?
No — the USDA PLANTS Database lists Potato Yam as introduced rather than native in the Lower 48, so it is not part of Ohio's native flora. It grows here as a garden plant; pairing it with a few Ohio natives keeps local pollinators fed too.
How should I amend the soil for Potato Yam in Ohio?
Potato Yam prefers pH 5.3-8 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Ohio soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Potato Yam actually grow on my specific land in Ohio?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores potato yam against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Ohio
State-level data is a sketch. Your Growable Ground report scores potato yam against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Ohio potato yam averages can't show:
We read public map data around Ohio — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ohio potato yam average
Explore More
Growing guides for potato yam
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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