How to Grow Safflowers
On this page
Safflower starts life as a low rosette that's surprisingly frost-hardy, shrugging off temperatures down to about -6.7°C, but once the stem begins to elongate toward flowering it becomes very sensitive to frost. Aim to get plants past the rosette stage before your last hard frost, then give them warm, sunny, dry conditions through flowering and seed-fill.
The short answer
- 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
Quick Facts
At a Glance
Diseases
Pests
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).
Safflower Photo Gallery
Plan your Safflowers planting
Timing for Safflowers follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. 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
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
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
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
Get the Global Garden Planner →Instant PDF download · Works in either hemisphere
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 international horticultural research and extension sources. 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):
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.