Yes — Strong Match
safflower (zones 2-11) covers every zone Indiana contains (5b-7b), so hardiness is not what limits it anywhere in the state.
Your yard isn't the whole zone.
Safflower is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Indiana site runs ~209 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 safflower against your land's actual frost dates, sun, and soil.
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Zone Comparison
Safflower Needs
- USDA Zones: 2-11
- Frost-Free Days: 120+
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~60 days of harvest
- Drought tolerance: High
Indiana Has
- USDA Zones: 5b-7b
- Last Hard Freeze (28°F): Apr 4 - Apr 9
- First Hard Freeze (28°F): Oct 30 - Nov 4
- Annual Rainfall: 36-46 inches
- Common Soils: Silt loam, Clay loam, Glacial till
Plant Zone Range (zones 2-11)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Safflower in Indiana
The frost window
Across Indiana, the last spring hard freeze (28°F) clears between Apr 4 and Apr 9, and the first fall hard freeze lands between Oct 30 and Nov 4 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 204-day window you can count on — up to 214 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 tenderness
Safflower is frost-tender — its listed minimum temperature is 41°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
When to start the seed
Safflower is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Indiana'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 120 days to maturity (USDA PLANTS Database), counting from the last hard freeze it ripens with 84 days to spare even in Indiana's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Steuben 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
The zone check says safflower survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Safflower wants 120+ frost-free days; a typical Indiana site sees ~209 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Safflower needs ~2000 GDD (base 50°F) to ripen. The state median runs ~3153 GDD (from PRISM 1991-2020 climate normals), so Indiana'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
Safflower tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Indiana. 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 6.5 and 7.5 — worth knowing before you decide whether a Indiana soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Indiana site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 37.8% of Indiana as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Safflower tolerates drought well, so wet feet — not dry spells — is its real risk here — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Indiana soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Safflower in Indiana — Quick Answer
- Verdict: Yes — Strong Match
- Plant Zones: 2-11 (USDA PLANTS Database)
- State Zones: 5b-7b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 4 - Apr 9 to Oct 30 - Nov 4 (NOAA Regional Climate Centers ACIS, 1991-2020)
- Days to Maturity: 120 days
What Else to Consider for Safflower in Indiana
Zone compatibility tells you about winter cold survival — but Indiana growers also need to think about:
Heavy clay soils limit drainage in many areas
Late spring frosts through early May
Hot humid summers promote blight and mildew
Growing safflower here specifically
Safflower rates to USDA zones 2–11 and is hardy to about 41°F, but cold isn't the risk in Indiana — wet is: with roughly 37.8% of its soils poorly-drained (SSURGO), soggy ground rots the roots.
Give safflower a raised bed or mounded row with coarse amendment so its roots never sit wet. How to handle it →
What to actually do about these — and the constraints that apply to every Indiana grower, not just safflower — is covered on the Indiana growing guide.
Timing shifts within Indiana
Indiana isn't one climate. In Steuben County, the last hard freeze (28°F) holds until about Apr 18 — roughly 11 days later than the recorded state median — so plant safflower to your county's window, not the statewide date.
Safflower needs about 120 days of frost-free season to complete its cycle. Even Steuben County — Indiana’s shortest season at 191 frost-free days — clears that by 71 days, so season length isn’t the constraint anywhere in Indiana. What varies is your own parcel.
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"). Safflower's 120-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in Indiana Fits Best
Even within Indiana's zones 5b-7b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for safflower (USDA PHZM 2023):
Pollinator + Wildlife Value
Safflower 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, safflower can only work that bloom inside Indiana's frost window — roughly 209 days, opening after the last 28°F freeze (Apr 4 - Apr 9) and closing at the first (Oct 30 - Nov 4), per NOAA Regional Climate Centers ACIS, 1991-2020.
Recommended Safflower Varieties for Indiana
Indiana publishes no state variety trial for safflower, so we won't invent a "best for Indiana" list. Choose types rated to your USDA hardiness zone (5b-7b), and confirm winter survival and drainage against your own parcel.
Indiana Cooperative Extension
For Indiana-specific cultivar recommendations, planting calendars, and pest pressure for safflower, the canonical source is Purdue Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Safflower native to Indiana?
No — the USDA PLANTS Database lists Safflower as introduced rather than native in the Lower 48, so it is not part of Indiana's native flora. It grows here as a garden plant; pairing it with a few Indiana natives keeps local pollinators fed too.
Looking for plants that belong here? The Indiana 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 Safflower in Indiana
When can I plant Safflower in Indiana?
Indiana's last spring hard freeze (28°F) clears between Apr 4 and Apr 9, and the first fall hard freeze lands between Oct 30 and Nov 4 (NOAA Regional Climate Centers ACIS, 1991-2020). Safflower is frost-tender — its listed minimum temperature is 41°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Safflower mature before first frost in Indiana?
Yes — Safflower matures in 120 days (USDA PLANTS Database), and Indiana's dependable hard-freeze-free window runs 204 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 84 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 Safflower grown in across Indiana?
Indiana spans USDA hardiness zones 5b-7b (USDA ARS PHZM 2023). Safflower 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 Indiana site have?
A typical Indiana site sees ~209 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Safflower needs 120+ 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 Steuben, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Safflower native to Indiana?
No — the USDA PLANTS Database lists Safflower as introduced rather than native in the Lower 48, so it is not part of Indiana's native flora. It grows here as a garden plant; pairing it with a few Indiana natives keeps local pollinators fed too.
How should I amend the soil for Safflower in Indiana?
Safflower tolerates pH 5-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Indiana site — amend for drainage and organic matter first.
Will Safflower actually grow on my specific land in Indiana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores safflower 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 Indiana
State-level data is a sketch. Your Growable Ground report scores safflower against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Indiana safflower averages can't show:
We read public map data around Indiana — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Indiana safflower average
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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