Conditional — Some Areas
sunn hemp (zones 7-11) has limited zone overlap with Alaska (1a-7b). Only zones 7-7 in the state are suitable.
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, and slope, trees, and low spots move the last-frost date across a single yard. Enter your address and we'll score sunn hemp against your parcel's actual frost dates, sun, and soil.
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Zone Comparison
Sunn Hemp Needs
- USDA Zones: 7-11
- Soil pH: 5 - 8.4
- Sun: Full Sun
- Drainage: well (dry spells)
- Frost-Free Days: 60+
Alaska Has
- USDA Zones: 1a-7b
- Last Frost: May 1 - Jun 15
- First Frost: Aug 15 - Oct 1
- Annual Rainfall: 10-160 inches
- Common Soils: Permafrost, Glacial silt, Volcanic ash
Plant Zone Range (zones 7-11)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Sunn Hemp in Alaska
The frost window
Across Alaska, the last spring frost clears between May 1 and Jun 15, and the first fall frost lands between Aug 15 and Oct 1 (NOAA Climate Normals 1991-2020). Counting from the latest last frost to the earliest first frost, that's a 61-day window you can count on — up to 153 days on a mild site in a kind year.
Frost tenderness
Sunn Hemp is frost-tender — its listed minimum temperature is 39.2°F (USDA PLANTS Database) — so set plants out after the last frost has cleared your local site, not the state's earliest date.
Days to maturity vs. the window
At 90 days to maturity (USDA PLANTS Database), the fit is tight: Alaska's dependable window runs 61 days. Starting seeds indoors and transplanting at the front of the window banks the difference.
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
Zone compatibility says you can survive winter here. Whether the growing season is long enough — and warm enough — is a different question.
Frost-free days
Sunn Hemp wants 60+ frost-free days; a typical Alaska site sees ~130 (NOAA Climate Normals). That leaves comfortable headroom for succession planting.
Growing degree days
Sunn Hemp needs ~2200 GDD (base 50°F) to ripen. The state median runs ~2000 GDD (USDA NRCS county aggregates), so Alaska's typical season runs short on heat — pick a south-facing site and consider season extension.
Climate aggregates derive from USDA NRCS county-level hardiness data + Cornell CALS Extension GDD-by-region tables + MSU Extension chill-hours-by-zone (1991-2020 NOAA Climate Normals baseline).
Soil + Drainage Fit
Sunn Hemp likes near-neutral soil (pH 5-8.4). That's the common-ground band across Alaska's permafrost and glacial silt — a soil test confirms it for your site. Drainage matters: this plant wants well (dry spells). If your Alaska site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH and drainage requirements from USDA PLANTS Database. Alaska soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Sunn Hemp in Alaska — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 7-11 (USDA PLANTS Database)
- State Zones: 1a-7b (USDA ARS PHZM 2023)
- Growing Season: May 1 - Jun 15 to Aug 15 - Oct 1 (NOAA Climate Normals)
- Days to Maturity: 90 days
What Else to Consider
Zone compatibility tells you about winter cold survival — but Alaska growers also need to think about:
Extremely short growing season (70-110 frost-free days)
A high tunnel or greenhouse is standard Alaska practice — it turns 90 outdoor days into a real growing season.
Permafrost prevents deep root growth in many areas
Raised beds lift roots above the cold and warm weeks earlier in spring — the proven northern workaround.
Limited soil development in glacial terrain
Start with a soil test to see what glacial ground actually has, then build up with imported topsoil and steady compost.
Pollinator + Wildlife Value
Sunn Hemp draws pollinators (moderate value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Alaska Cooperative Extension
For Alaska-specific cultivar recommendations, planting calendars, and pest pressure for sunn hemp, the canonical source is UAF Cooperative Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sunn Hemp native to Alaska?
No — the USDA PLANTS Database lists Sunn Hemp as introduced rather than native in the Lower 48, so it is not part of Alaska's native flora. It grows here as a garden plant; pairing it with a few Alaska natives keeps local pollinators fed too.
Looking for plants that belong here? The Alaska 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 Alaska
When can I plant Sunn Hemp in Alaska?
Alaska's last spring frost clears between May 1 and Jun 15, and the first fall frost lands between Aug 15 and Oct 1 (NOAA Climate Normals 1991-2020). Sunn Hemp is frost-tender — its listed minimum temperature is 39.2°F (USDA PLANTS Database) — so wait until the last frost has cleared your specific site before planting out.
Can Sunn Hemp mature before first frost in Alaska?
It's close: Sunn Hemp needs 90 days to mature (USDA PLANTS Database) against Alaska's 61-day dependable window (NOAA Climate Normals 1991-2020). Start seeds indoors and transplant right after last frost to bank the missing days.
What hardiness zone is Sunn Hemp grown in across Alaska?
Alaska spans USDA hardiness zones 1a-7b (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 Alaska site have?
A typical Alaska site sees ~130 frost-free days per year (derived from NOAA Climate Normals 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 Alaska?
No — the USDA PLANTS Database lists Sunn Hemp as introduced rather than native in the Lower 48, so it is not part of Alaska's native flora. It grows here as a garden plant; pairing it with a few Alaska natives keeps local pollinators fed too.
How should I amend the soil for Sunn Hemp in Alaska?
Sunn Hemp prefers pH 5-8.4 and well (dry spells) drainage (USDA PLANTS Database). That sits in the common-ground band across Alaska soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Sunn Hemp actually grow on my specific land in Alaska?
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 Alaska
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 exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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