How to Grow Safflowers USA
On this page
In the US, safflowers go in the ground mid February to early March.
Timing is the decision that matters most in the USA: there are 7 separate regional sowing windows, ranging from mid January in Deep South & Gulf Coast to mid April in Intermountain West.
The short answer
- Plant
- Mid February to early March
- Site
- 6+ hours of sun, soil pH 6–7.5
- Biggest risk
- Alternaria leaf spot of safflower
Core growing advice on this page is checked against named horticultural sources — see References.
Safflower (Carthamus tinctorius)
3 sources cited · Verified
Regional Planting Calendar
| Region | Sow |
|---|---|
| Pacific Northwest derived | mid February to early March |
| Northeast & New England derived | mid March to early April |
| Lower Midwest & Ohio Valley derived | late March to mid April |
| Intermountain West derived | mid April to early May |
| N. Plains & Upper Midwest derived | early April to late April |
| Mid-Atlantic & Upper South derived | mid March to early April |
| Deep South & Gulf Coast derived | mid January to early February |
Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.
Pacific Northwest - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 8 March (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 15 February to 8 March. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Northeast & New England - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 6 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 16 March to 6 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Lower Midwest & Ohio Valley - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 16 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 26 March to 16 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Intermountain West - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 6 May (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 15 April to 6 May. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
N. Plains & Upper Midwest - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 25 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 4 April to 25 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Mid-Atlantic & Upper South - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 4 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 14 March to 4 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Deep South & Gulf Coast - detail & sources
DERIVED from this region's own frost normal, not quoted for the region. Rosette tolerates temperatures as low as 20°F, so safflower is direct-seeded before the last frost -- around late April to early May in the Upper Midwest, with a planting-depth of 1-1.5in; risk increases if planted after mid-May. Applied to a mean last frost of 2 February (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 12 January to 2 February. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.
Quick Facts
At a Glance
Soil & Growing Conditions
Growth Stages
Harvest & Storage
When to pick: Ready to harvest when most of the leaves turn brown and the seeds are white and hand-thresh easily; typically early to late September in the northern US (Wisconsin Extension). Takes 110-140 days from planting to maturity (Wisconsin Extension; NDSU).
Diseases
Pests
Safflower Photo Gallery
Plan your Safflowers planting
When to sow and plant Safflowers depends on your own frost dates. Check the USA vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Safflower in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
Sources
-
In North Dakota, safflower normally requires 110-120 days from emergence to maturity. Grows best on deep, fertile, well-drained loam soils with good water-holding capacity; soil pH of 6.0 appears adequate. Planting depths of 1-1.5in are optimum, do not seed deeper than 2in. Taproot can penetrate 8-10ft in deep soils.
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Deep, fertile, well-drained soil with high water-holding capacity; soil pH of 6.0 adequate; high soil salinity reduces germination. Planting depth 1-1.5in. Seeding rate 20-25 lb/acre dryland, 25-35 lb/acre irrigated. Row spacing 6-7in, ~6 plants/sq ft. Plant late April to early May in the Upper Midwest; risk if planted after mid-May. Days to maturity 110-140. Tolerates temperatures as low as 20°F at the rosette stage, but is very frost-sensitive after stem elongation. Needs a minimum 120 frost-free days and 2200 growing degree days; not recommended above 15in annual precipitation; prefers warm, sunny, dry conditions during flowering and seed-fill. Diseases: Alternaria leaf spot (Alternaria carthami) causing large, brown, irregular leaf spots; bacterial blight (Pseudomonas syringae) with yellow-green margined lesions; Sclerotinia and Botrytis flower-head rots; various root rots and wilts. Pests: wireworms, cutworms and seed corn maggots damage seeds/seedlings; thrips, lygus bugs, grasshoppers and sunflower moths damage later growth -- sunflower moth can cause 20-30% loss if damage occurs early in flowering. Harvest when most leaves turn brown and seeds are white and hand-thresh easily; early to late September in the Upper Midwest.
These 2 sources are specific to this region. The full list of 3 sources behind this guide (NDSU Agriculture Extension, Royal Horticultural Society, Wisconsin Corn Agronomy, University of Wisconsin-Madison Division of Extension) is in the references of our UK guide to safflowers; they describe the plant itself, which is the same wherever it grows.
Frequently Asked Questions
When should I sow safflowers in the USA?
In Deep South & Gulf Coast, from mid January. In Intermountain West, wait until mid April. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow safflowers?
Sow mid January to early May.
What soil pH do safflowers need?
A pH of about 6–7.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect safflowers?
Our data links 2 diseases and 6 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.
Get the USA Garden Planner →Instant PDF download · Written for US growing conditions
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against USDA hardiness-zone and frost-date data, with Cooperative Extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Last verified 2026-09-03
Related guides
More from the same group (grains & pseudo-grains):
Growing advice for your part of the USA
Timing and conditions change a lot inside one country. These guides cover frost dates and growing seasons region by region.
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.