Unlikely — Zone Mismatch
neka (Simbo) (zones 8-11) does not overlap with Iowa's zone range (4b-6a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Neka Simbo is hardy to zone 8, and the warmest ground in Iowa is zone 6 — 2 zones short. Planted in open ground it will not survive a Iowa winter. To grow it here, grow neka simbo in an earth-sheltered greenhouse — its modeled 2.5-zone lift covers this gap.
An earth-sheltered greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 8-11 (plant) against 4-6 (Iowa). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['earth_sheltered'] (+2.5 zones) via api/fast_sections.py Unlock Engine v2.
Neka Simbo in Iowa — the short answer
Neka Simbo in Iowa: hardy in zones 8–11, full sun, against a state median of ~189 frost-free days.
- Plant zones
- 8-11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Iowa zones
- 4b-6a
- USDA PHZM 2023
- Frost window
- Apr 10 - Apr 17 – Oct 18 - Oct 23
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 168 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Iowa spans zones 4b-6a, 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 neka simbo against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Iowa is not one climate
Iowa’s winter-low ladder runs across 99 counties, from zone 4.5 in Clayton County to zone 6 in Lee County. That is 15°F between the two counties’ average coldest night — the difference between neka simbo overwintering in the ground and coming under cover.
The middle half of 99 counties runs 5–5.5 zones, with a median of 5 zones — a 1.5-zone span end to end.
Measured across 99 Iowa counties. USDA PHZM 2023, per county. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where Neka Simbo Stands in Iowa
Neka Simbo is rated for zones 8–11 — a cold floor USDA puts at 10 to 20°F. No Iowa county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Iowa winters, not about neka simbo.
Below the zone 8 floor
99 counties
- Clayton County · zone 4b
- Howard County · zone 4b
- Winneshiek County · zone 4b
3 of 99 shown
Winter cold is the limit here — the same plant works in a container that comes under cover.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Neka Simbo Needs
- USDA Zones: 8-11
- Frost-Free Days: 365+
- Sun: Full Sun
Iowa Has
- USDA Zones: 4b-6a
- Last Hard Freeze (28°F): Apr 10 - Apr 17
- First Hard Freeze (28°F): Oct 18 - Oct 23
- Annual Rainfall: 26-36 inches
- Common Soils: Prairie loess, Silt loam, Clay loam
Plant Zone Range (zones 8-11)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Neka Simbo in Iowa
The frost window
Across Iowa, the last spring hard freeze (28°F) clears between Apr 10 and Apr 17, and the first fall hard freeze lands between Oct 18 and Oct 23 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 184-day window you can count on — up to 196 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
Iowa runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for neka simbo, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether neka simbo is a permanent planting or a replant-every-spring crop for you turns on your own zone within Iowa; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Howard County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. 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 neka simbo does not survive a Iowa 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 Iowa under protection.
Frost-free days
Neka Simbo wants 365+ frost-free days; a typical Iowa site sees ~189 (NOAA Regional Climate Centers ACIS, 1991-2020) — 176 days short of what it needs. A typical Iowa season does not carry this crop to harvest outdoors, and a gap that size is not one an earlier sowing date or a faster cultivar closes; growing it here means growing it under cover.
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
Neka Simbo tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Iowa. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 7 — worth knowing before you decide whether a Iowa soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Iowa 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 42.9% of Iowa as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Neka Simbo 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 requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Iowa soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Neka Simbo in Iowa
Zone compatibility tells you about winter cold survival — but Iowa growers also need to think about:
Cold winters reaching -20F or below
Variable spring weather delays planting
Wind exposure on open prairies desiccates plants
Growing neka simbo here specifically
Neka Simbo roots run medium and prefer pH 5.0–8.0, but drainage comes first here: SSURGO maps about 42.9% of Iowa as poorly or somewhat-poorly drained, and wet ground rots its crown before pH ever matters.
Plant neka simbo 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 Iowa grower, not just neka simbo — is covered on the Iowa growing guide.
Timing shifts within Iowa
Iowa isn't one climate. In Howard County, the last hard freeze (28°F) holds until about Apr 24 — roughly 10 days later than the recorded state median — so plant neka simbo to your county's window, not the statewide date.
Neka Simbo needs about 365 days of frost-free season to complete its cycle. No Iowa county gives it that outdoors: even Lee County, the state’s longest season at 216 frost-free days, falls 149 days short — so it needs transplants, a short-season variety, or covered growing.
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"). Neka Simbo's 365-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
Neka Simbo draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, neka simbo can only work that bloom inside Iowa's frost window — roughly 189 days, opening after the last 28°F freeze (Apr 10 - Apr 17) and closing at the first (Oct 18 - Oct 23), per NOAA Regional Climate Centers ACIS, 1991-2020.
Iowa Cooperative Extension
For Iowa-specific cultivar recommendations, planting calendars, and pest pressure for neka simbo, the canonical source is Iowa State University Extension and Outreach. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Neka Simbo in Iowa
When can I plant Neka Simbo in Iowa?
Iowa's last spring hard freeze (28°F) clears between Apr 10 and Apr 17, and the first fall hard freeze lands between Oct 18 and Oct 23 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Neka Simbo, so this page does not state whether it overwinters in Iowa 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 Neka Simbo grown in across Iowa?
Iowa spans USDA hardiness zones 4b-6a (USDA ARS PHZM 2023). Neka Simbo carries a range of zones 8-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Iowa site have?
A typical Iowa site sees ~189 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Neka Simbo needs 365+ 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 Howard, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Neka Simbo in Iowa?
Neka Simbo tolerates pH 5-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Iowa site — amend for drainage and organic matter first.
Will Neka Simbo actually grow on my specific land in Iowa?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores neka simbo 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 Iowa
State-level data is a sketch. Your Growable Ground report scores neka simbo against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Iowa neka simbo averages can't show:
We read public map data around Iowa — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Iowa neka simbo average
Explore More
Growing guides for neka simbo
Explore Iowa county by county
Iowa carries 99 counties with their own USDA zone — a sample of the growing pages for neka simbo there:
Where else neka simbo grows
Neka Simbo's zone band crosses state lines — these are the states closest to Iowa in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Iowa
Iowa has a growing page for 806 plants — a rotating sample of the rest of the shelf.
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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