Yes — Strong Match
nigella (zones 2-10) covers every zone Tennessee contains (6a-8a), so hardiness is not what limits it anywhere in the state.
Nigella in Tennessee — the short answer
Nigella in Tennessee: hardy in zones 2–10, full sun, against a state median of ~230 frost-free days.
- Plant zones
- 2-10
- 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
- Tennessee zones
- 6a-8a
- USDA PHZM 2023
- Frost window
- Mar 21 - Mar 29 – Nov 5 - Nov 12
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 193 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 70 days
- Growable Ground Plant Database
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.
Nigella is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Tennessee site runs ~230 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score nigella against your land's actual frost dates, sun, and soil.
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Tennessee is not one climate
A single Tennessee answer averages 95 counties whose growing seasons are 73 days apart — from 193 frost-free days in Johnson County to 266 in Shelby County. Which end of that your land sits nearer changes what nigella can finish before the first hard freeze.
The middle half of 95 counties runs 221–235 days, with a median of 230 days — a 73-day span end to end.
Measured across 95 Tennessee counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. 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 in Tennessee Fits Best
Even within Tennessee's zones 6a-8a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for nigella (USDA PHZM 2023):
Zone Comparison
Nigella Needs
- USDA Zones: 2-10
- Frost-Free Days: 100+
- Sun: Full Sun
- Mature size: 1.8 ft tall
- Picking window: ~60 days of harvest
- Drought tolerance: Medium
Tennessee Has
- USDA Zones: 6a-8a
- Last Hard Freeze (28°F): Mar 21 - Mar 29
- First Hard Freeze (28°F): Nov 5 - Nov 12
- Annual Rainfall: 45-55 inches
- Common Soils: Silt loam, Clay loam, Limestone-derived
Plant Zone Range (zones 2-10)
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 Nigella in Tennessee
The frost window
Across Tennessee, the last spring hard freeze (28°F) clears between Mar 21 and Mar 29, and the first fall hard freeze lands between Nov 5 and Nov 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 221-day window you can count on — up to 236 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.
Frost hardiness
Nigella takes cold down to about 25°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Tennessee's window — even a few weeks before the final hard freeze. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Nigella is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Tennessee's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 70 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 151 days to spare even in Tennessee's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Johnson 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 nigella survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Nigella wants 100+ frost-free days; a typical Tennessee site sees ~230 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Nigella needs ~900 GDD (base 50°F) to ripen. The state median runs ~4122 GDD (from PRISM 1991-2020 climate normals), so Tennessee's typical season clears that easily.
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
Nigella likes near-neutral soil (pH 6-8). That's the common-ground band across Tennessee's silt loam and clay loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.5 and 7.3 — worth knowing before you decide whether a Tennessee soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Tennessee site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Tennessee's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Nigella needs about 19 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how nigella performs.
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. Tennessee soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Nigella in Tennessee
Zone compatibility tells you about winter cold survival — but Tennessee growers also need to think about:
Heavy clay soils in the Nashville Basin
High humidity promotes disease in summer
Variable spring weather with late frost risk
Growing nigella here specifically
Nigella wants pH 6.0–8.0 and rates to USDA zones 2–10, but Tennessee's soils are dominantly silt loam — the fit is decided by your parcel's own map unit, not the state average.
Match nigella to your parcel's SSURGO map unit — test pH and texture, and amend toward its 6.0–8.0 range. How to handle it →
What to actually do about these — and the constraints that apply to every Tennessee grower, not just nigella — is covered on the Tennessee growing guide.
Timing shifts within Tennessee
Tennessee isn't one climate. In Johnson County, the last hard freeze (28°F) holds until about Apr 14 — roughly 21 days later than the recorded state median — so plant nigella to your county's window, not the statewide date.
Nigella needs about 100 days of frost-free season to complete its cycle. Even Johnson County — Tennessee’s shortest season at 193 frost-free days — clears that by 93 days, so season length isn’t the constraint anywhere in Tennessee. What varies is your own parcel.
Across Tennessee’s 95 counties the frost-free season runs from 193 days in Johnson County to 266 days in Shelby County — a spread of 73 days, which is why a single statewide planting date misleads. The median Tennessee county sees 230 frost-free days, leaving nigella about 130 days of slack on a typical parcel — room for a second sowing where the season runs long.
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"). Nigella's 100-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
Nigella draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, nigella can only work that bloom inside Tennessee's frost window — roughly 230 days, opening after the last 28°F freeze (Mar 21 - Mar 29) and closing at the first (Nov 5 - Nov 12), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Nigella
Nigella is listed as toxic to dogs, cats (seeds) at a mild level (Pet Poison Helpline). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Tennessee this is a one-season plant and the first hard freeze (Nov 5 - Nov 12) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Nigella Varieties for Tennessee
Tennessee publishes no state variety trial for nigella, so we won't invent a "best for Tennessee" list. Choose types rated to your USDA hardiness zone (6a-8a), and confirm winter survival and drainage against your own parcel.
Tennessee Cooperative Extension
For Tennessee-specific cultivar recommendations, planting calendars, and pest pressure for nigella, the canonical source is UT Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Nigella native to Tennessee?
No — the USDA PLANTS Database lists Nigella as introduced rather than native in the Lower 48, so it is not part of Tennessee's native flora. It grows here as a garden plant; pairing it with a few Tennessee natives keeps local pollinators fed too.
Looking for plants that belong here? The Tennessee 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 Nigella in Tennessee
When can I plant Nigella in Tennessee?
Tennessee's last spring hard freeze (28°F) clears between Mar 21 and Mar 29, and the first fall hard freeze lands between Nov 5 and Nov 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Nigella takes cold to about 25°F before a freeze kills it (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor), so plant on the early side of that window — even ahead of the final hard freeze.
Can Nigella mature before first frost in Tennessee?
Yes — Nigella matures in 70 days (Growable Ground Plant Database), and Tennessee's dependable hard-freeze-free window runs 221 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 151 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Nigella grown in across Tennessee?
Tennessee spans USDA hardiness zones 6a-8a (USDA ARS PHZM 2023). Nigella carries a range of zones 2-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Tennessee site have?
A typical Tennessee site sees ~230 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Nigella needs 100+ 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 Johnson, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Nigella native to Tennessee?
No — the USDA PLANTS Database lists Nigella as introduced rather than native in the Lower 48, so it is not part of Tennessee's native flora. It grows here as a garden plant; pairing it with a few Tennessee natives keeps local pollinators fed too.
How should I amend the soil for Nigella in Tennessee?
Nigella prefers pH 6-8 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Tennessee soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Nigella actually grow on my specific land in Tennessee?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores nigella 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 Tennessee
State-level data is a sketch. Your Growable Ground report scores nigella against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Tennessee nigella averages can't show:
We read public map data around Tennessee — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tennessee nigella average
Explore More
Growing guides for nigella
Explore Tennessee county by county
Tennessee carries 95 counties with their own USDA zone — a sample of the growing pages for nigella there:
Where else nigella grows
Nigella's zone band crosses state lines — these are the states closest to Tennessee 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 Tennessee
Tennessee has a growing page for 1,020 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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