Generally — Most Areas
rapeseed (zones 4-10) suits most of Wisconsin (3b-6a) — zones 4-6 are in range, and the rest of the state is the exception.
Rapeseed in Wisconsin — the short answer
Rapeseed in Wisconsin: hardy in zones 4–10, full sun, against a state median of ~173 frost-free days.
- Plant zones
- 4-10
- 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
- Wisconsin zones
- 3b-6a
- USDA PHZM 2023
- Frost window
- Apr 17 - May 2 – Oct 9 - Oct 21
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 140 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 75 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.
Rapeseed is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Wisconsin site runs ~173 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 rapeseed against your land's actual frost dates, sun, and soil.
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Wisconsin is not one climate
A single Wisconsin answer averages 72 counties whose growing seasons are 77 days apart — from 140 frost-free days in Florence County to 217 in Milwaukee County. Which end of that your land sits nearer changes what rapeseed can finish before the first hard freeze.
The middle half of 72 counties runs 158–187 days, with a median of 173 days — a 77-day span end to end.
Measured across 72 Wisconsin 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 Wisconsin Fits Best
Even within Wisconsin's zones 3b-6a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for rapeseed (USDA PHZM 2023):
Zone Comparison
Rapeseed Needs
- USDA Zones: 4-10
- Frost-Free Days: 90+
- Sun: Full Sun
- Mature size: 4 ft tall
- Drought tolerance: Medium
Wisconsin Has
- USDA Zones: 3b-6a
- Last Hard Freeze (28°F): Apr 17 - May 2
- First Hard Freeze (28°F): Oct 9 - Oct 21
- Annual Rainfall: 28-34 inches
- Common Soils: Silt loam, Clay loam, Sandy outwash
Plant Zone Range (zones 4-10)
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 Rapeseed in Wisconsin
The frost window
Across Wisconsin, the last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 187 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
Rapeseed takes cold down to about 10°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Wisconsin'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
Rapeseed is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Wisconsin'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 75 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 85 days to spare even in Wisconsin'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 rapeseed survives winter in part of Wisconsin, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Rapeseed wants 90+ frost-free days; a typical Wisconsin site sees ~173 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Rapeseed needs ~1000 GDD (base 50°F) to ripen. The state median runs ~2102 GDD (from PRISM 1991-2020 climate normals), so Wisconsin'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
Rapeseed tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Wisconsin. 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 7.5 — worth knowing before you decide whether a Wisconsin soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Wisconsin 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. Wisconsin soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Rapeseed in Wisconsin
Zone compatibility tells you about winter cold survival — but Wisconsin growers also need to think about:
Cold winters (-30F in northern WI)
Short growing season (110-140 frost-free days)
Sandy central soils drain too quickly
What to actually do about these — and the constraints that apply to every Wisconsin grower, not just rapeseed — is covered on the Wisconsin growing guide.
Timing shifts within Wisconsin
Rapeseed needs about 90 days of frost-free season to complete its cycle. Even Florence County — Wisconsin’s shortest season at 140 frost-free days — clears that by 50 days, so season length isn’t the constraint anywhere in Wisconsin. What varies is your own parcel.
Across Wisconsin’s 72 counties the frost-free season runs from 140 days in Florence County to 217 days in Milwaukee County — a spread of 77 days, which is why a single statewide planting date misleads. The median Wisconsin county sees 173 frost-free days, leaving rapeseed about 83 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"). Rapeseed'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
Rapeseed draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, rapeseed can only work that bloom inside Wisconsin's frost window — roughly 173 days, opening after the last 28°F freeze (Apr 17 - May 2) and closing at the first (Oct 9 - Oct 21), per NOAA Regional Climate Centers ACIS, 1991-2020.
Wisconsin Cooperative Extension
For Wisconsin-specific cultivar recommendations, planting calendars, and pest pressure for rapeseed, the canonical source is UW–Madison Division of Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Rapeseed native to Wisconsin?
No — the USDA PLANTS Database lists Rapeseed as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.
Looking for plants that belong here? The Wisconsin 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 Rapeseed in Wisconsin
When can I plant Rapeseed in Wisconsin?
Wisconsin's last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Rapeseed takes cold to about 10°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 Rapeseed mature before first frost in Wisconsin?
Yes — Rapeseed matures in 75 days (Growable Ground Plant Database), and Wisconsin's dependable hard-freeze-free window runs 160 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 85 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 Rapeseed grown in across Wisconsin?
Wisconsin spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Rapeseed carries a range of zones 4-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Wisconsin site have?
A typical Wisconsin site sees ~173 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Rapeseed needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Rapeseed native to Wisconsin?
No — the USDA PLANTS Database lists Rapeseed as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.
How should I amend the soil for Rapeseed in Wisconsin?
Rapeseed tolerates pH 5-8 and well (dry spells) drainage (Growable Ground Plant Database). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Wisconsin site — amend for drainage and organic matter first.
Will Rapeseed actually grow on my specific land in Wisconsin?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores rapeseed 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 Wisconsin
State-level data is a sketch. Your Growable Ground report scores rapeseed against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Wisconsin rapeseed averages can't show:
We read public map data around Wisconsin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Wisconsin rapeseed average
Explore More
Growing guides for rapeseed
Explore Wisconsin county by county
Wisconsin carries 72 counties with their own USDA zone — a sample of the growing pages for rapeseed there:
Where else rapeseed grows
Rapeseed's zone band crosses state lines — these are the states closest to Wisconsin 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 Wisconsin
Wisconsin has a growing page for 806 plants — a rotating sample of the rest of the shelf.
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