Conditional — Some Areas
sunflower (zones 2-11) has limited zone overlap with Kansas (5b-7a). Only zones 5-7 in the state are suitable.
Your yard isn't the whole zone.
Sunflower 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 sunflower against your parcel's actual frost dates, sun, and soil.
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Zone Comparison
Sunflower Needs
- USDA Zones: 2-11
- Soil pH: 5.5 - 8
- Sun: Full Sun
- Drainage: well (dry spells)
- Frost-Free Days: 70+
Kansas Has
- USDA Zones: 5b-7a
- Last Frost: Apr 5 - May 1
- First Frost: Oct 5 - Oct 30
- Annual Rainfall: 16-42 inches
- Common Soils: Prairie loam, Silt loam, Clay
Plant Zone Range (zones 2-11)
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 Sunflower in Kansas
The frost window
Across Kansas, the last spring frost clears between Apr 5 and May 1, and the first fall frost lands between Oct 5 and Oct 30 (NOAA Climate Normals 1991-2020). Counting from the latest last frost to the earliest first frost, that's a 157-day window you can count on — up to 208 days on a mild site in a kind year.
Frost tenderness
Sunflower is frost-tender — its listed minimum temperature is 41°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 80 days to maturity (USDA PLANTS Database), a planting right after last frost ripens with 77 days to spare even in Kansas's tightest frost scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Thomas County, not the statewide average.
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
Sunflower wants 70+ frost-free days; a typical Kansas site sees ~190 (NOAA Climate Normals). That leaves comfortable headroom for succession planting.
Growing degree days
Sunflower needs ~1500 GDD (base 50°F) to ripen. The state median runs ~3850 GDD (USDA NRCS county aggregates), so Kansas's typical season clears that easily.
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
Sunflower likes near-neutral soil (pH 5.5-8). That's the common-ground band across Kansas's prairie loam and silt loam — a soil test confirms it for your site. Drainage matters: this plant wants well (dry spells). If your Kansas site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Kansas's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel — that map unit, not the state average, decides how sunflower performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Kansas soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Sunflower in Kansas — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 2-11 (USDA PLANTS Database)
- State Zones: 5b-7a (USDA ARS PHZM 2023)
- Growing Season: Apr 5 - May 1 to Oct 5 - Oct 30 (NOAA Climate Normals)
- Days to Maturity: 80 days
What Else to Consider
Zone compatibility tells you about winter cold survival — but Kansas growers also need to think about:
Low rainfall in western KS requires irrigation
Out west, drip lines and heavy mulch are the growing season — design the water before the beds.
Extreme wind and hail during severe storm season
Stage row cover for hail season and give young plants a windbreak — quick shelter saves seasons.
Hot dry summers with 100F+ days
Lean on the spring and fall windows, shade the summer survivors, and water deep and early in the day.
Growing sunflower here specifically
Sunflower prefers pH 5.5–8.0 and room to root medium; across much of Kansas, restrictive group-D subsoil (SSURGO) blocks that depth.
Build sunflower a deep raised bed of loose soil to bypass the dense subsoil entirely. How to handle it →
Timing shifts within Kansas
Kansas isn't one climate. In Thomas County, the last hard freeze (28°F) holds until about Apr 4 — roughly 19 days later than the recorded state median — so plant sunflower to your county's window, not the statewide date.
County last-freeze dates: NOAA/PRISM Climate Normals 1991-2020, 28°F threshold (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Sunflower draws pollinators (high value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Recommended Sunflower Varieties for Kansas
Kansas publishes no state variety trial for sunflower, so we won't invent a "best for Kansas" list. Choose types rated to your USDA hardiness zone (5b-7a), and confirm winter survival and drainage against your own parcel.
Kansas Cooperative Extension
For Kansas-specific cultivar recommendations, planting calendars, and pest pressure for sunflower, the canonical source is K-State Research and Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sunflower native to Kansas?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Sunflower as native to Kansas. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Sunflower in Kansas
When can I plant Sunflower in Kansas?
Kansas's last spring frost clears between Apr 5 and May 1, and the first fall frost lands between Oct 5 and Oct 30 (NOAA Climate Normals 1991-2020). Sunflower is frost-tender — its listed minimum temperature is 41°F (USDA PLANTS Database) — so wait until the last frost has cleared your specific site before planting out.
Can Sunflower mature before first frost in Kansas?
Yes — Sunflower matures in 80 days (USDA PLANTS Database), and Kansas's dependable frost-free window runs 157 days (NOAA Climate Normals 1991-2020), leaving 77 days of margin. Plant just after last frost and it ripens ahead of the first fall frost.
What hardiness zone is Sunflower grown in across Kansas?
Kansas spans USDA hardiness zones 5b-7a (USDA ARS PHZM 2023). Sunflower carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Kansas site have?
A typical Kansas site sees ~190 frost-free days per year (derived from NOAA Climate Normals 1991-2020). Sunflower needs 70+ 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 Thomas, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Sunflower native to Kansas?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Sunflower as native to Kansas. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Sunflower in Kansas?
Sunflower prefers pH 5.5-8 and well (dry spells) drainage (USDA PLANTS Database). That sits in the common-ground band across Kansas soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Sunflower actually grow on my specific land in Kansas?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores sunflower 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 Kansas
State-level data is a sketch. Your Growable Ground report scores sunflower 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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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 →