Yes — Strong Match
sunn hemp (zones 7-11) covers every zone Alabama contains (7b-9b), so hardiness is not what limits it anywhere in the state.
Sunn Hemp in Alabama — the short answer
Sunn Hemp in Alabama: hardy in zones 7–11, full sun, against a state median of ~266 frost-free days.
- Plant zones
- 7-11
- 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
- Alabama zones
- 7b-9b
- USDA PHZM 2023
- Frost window
- Feb 24 - Mar 16 – Nov 15 - Nov 28
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 225 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 90 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.
Sunn Hemp is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Alabama site runs ~266 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 sunn hemp against your land's actual frost dates, sun, and soil.
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Alabama is not one climate
A single Alabama answer averages 67 counties whose growing seasons are 72 days apart — from 225 frost-free days in Marion County to 297 in Mobile County. Which end of that your land sits nearer changes what sunn hemp can finish before the first hard freeze.
The middle half of 67 counties runs 244–277 days, with a median of 266 days — a 72-day span end to end.
Measured across 67 Alabama 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 Alabama Fits Best
Even within Alabama's zones 7b-9b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for sunn hemp (USDA PHZM 2023):
Zone Comparison
Sunn Hemp Needs
- USDA Zones: 7-11
- Frost-Free Days: 60+
- Sun: Full Sun
- Mature size: 6 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Medium
Alabama Has
- USDA Zones: 7b-9b
- Last Hard Freeze (28°F): Feb 24 - Mar 16
- First Hard Freeze (28°F): Nov 15 - Nov 28
- Annual Rainfall: 50-65 inches
- Common Soils: Red clay, Sandy loam, Alluvial
Plant Zone Range (zones 7-11)
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 Sunn Hemp in Alabama
The frost window
Across Alabama, the last spring hard freeze (28°F) clears between Feb 24 and Mar 16, and the first fall hard freeze lands between Nov 15 and Nov 28 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 244-day window you can count on — up to 277 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.
When to start the seed
Sunn Hemp is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Alabama'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 90 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 154 days to spare even in Alabama's tightest freeze scenario — room for a later start or a second sowing.
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 sunn hemp survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Sunn Hemp wants 60+ frost-free days; a typical Alabama site sees ~266 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Sunn Hemp needs ~2200 GDD (base 50°F) to ripen. The state median runs ~5383 GDD (from PRISM 1991-2020 climate normals), so Alabama'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
Sunn Hemp tolerates a wide pH range (pH 5-8.4) — 3.4 units, acid ground through alkaline — so soil acidity is rarely what limits it in Alabama. 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 6 and 7 — worth knowing before you decide whether a Alabama soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Alabama site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
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. Alabama soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Sunn Hemp in Alabama
Zone compatibility tells you about winter cold survival — but Alabama growers also need to think about:
Heavy clay soils in the Piedmont region
High humidity promotes fungal diseases
Fire ants are a persistent garden pest
What to actually do about these — and the constraints that apply to every Alabama grower, not just sunn hemp — is covered on the Alabama growing guide.
Timing shifts within Alabama
Sunn Hemp needs about 60 days of frost-free season to complete its cycle. Even Marion County — Alabama’s shortest season at 225 frost-free days — clears that by 165 days, so season length isn’t the constraint anywhere in Alabama. What varies is your own parcel.
Across Alabama’s 67 counties the frost-free season runs from 225 days in Marion County to 297 days in Mobile County — a spread of 72 days, which is why a single statewide planting date misleads. The median Alabama county sees 266 frost-free days, leaving sunn hemp about 206 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"). Sunn Hemp's 60-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
Sunn Hemp draws honeybees, native bees, and butterflies (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, sunn hemp can only work that bloom inside Alabama's frost window — roughly 266 days, opening after the last 28°F freeze (Feb 24 - Mar 16) and closing at the first (Nov 15 - Nov 28), per NOAA Regional Climate Centers ACIS, 1991-2020.
Alabama Cooperative Extension
For Alabama-specific cultivar recommendations, planting calendars, and pest pressure for sunn hemp, the canonical source is Alabama Cooperative Extension System. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sunn Hemp native to Alabama?
No — the USDA PLANTS Database lists Sunn Hemp as introduced rather than native in the Lower 48, so it is not part of Alabama's native flora. It grows here as a garden plant; pairing it with a few Alabama natives keeps local pollinators fed too.
Looking for plants that belong here? The Alabama 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 Sunn Hemp in Alabama
When can I plant Sunn Hemp in Alabama?
Alabama's last spring hard freeze (28°F) clears between Feb 24 and Mar 16, and the first fall hard freeze lands between Nov 15 and Nov 28 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Sunn Hemp mature before first frost in Alabama?
Yes — Sunn Hemp matures in 90 days (Growable Ground Plant Database), and Alabama's dependable hard-freeze-free window runs 244 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 154 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 Sunn Hemp grown in across Alabama?
Alabama spans USDA hardiness zones 7b-9b (USDA ARS PHZM 2023). Sunn Hemp carries a range of zones 7-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Alabama site have?
A typical Alabama site sees ~266 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Sunn Hemp needs 60+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Sunn Hemp native to Alabama?
No — the USDA PLANTS Database lists Sunn Hemp as introduced rather than native in the Lower 48, so it is not part of Alabama's native flora. It grows here as a garden plant; pairing it with a few Alabama natives keeps local pollinators fed too.
How should I amend the soil for Sunn Hemp in Alabama?
Sunn Hemp tolerates pH 5-8.4 and well (dry spells) drainage (FAO ECOCROP). That is a 3.4-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Alabama site — amend for drainage and organic matter first.
Will Sunn Hemp actually grow on my specific land in Alabama?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores sunn hemp 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 Alabama
State-level data is a sketch. Your Growable Ground report scores sunn hemp against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Alabama sunn hemp averages can't show:
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