How to Grow Safflower

Carthamus tinctorius · Also called: Kusum, Kusumbha, Kardai, Karadi, Cártamo, Carthame, Färberdistel, Aspir

A single safflower head opening against a bright sky, its many narrow florets bright yellow and orange, rising from stiff green bracts, with stiff spiny-edged leaves clasping the stem below.

Photo: Carl Davies, CSIRO, CC BY 3.0 (Wikimedia Commons)

Safflower is the crop for the water that is already in the ground. Its taproot goes down two or three metres and lives on moisture stored below the reach of most other crops, which makes it the sensible thing to sow on residual moisture after a wet season, where a shallow-rooted crop would fail. Kazakhstan, Russia, Mexico, the United States, India, China, Argentina and Turkey grow the most. It gives two quite different products: an oil pressed from the seed, and a dye and food colour from the orange florets that has been traded for four thousand years. Its hard limit is humidity. Safflower wants dry air from flowering onward, and a wet or muggy spell while the heads are open rots them where they stand, which is why it succeeds in dry countries and disappoints in wet ones.

Growing Safflower, Stage by Stage

1. Get the land ready — Choose deep soil holding stored moisture, break any pan, and make sure water can leave the field.
2. Choose your seed and planting material — Decide between spiny and spineless, and between oil and dye, because both choices change the work and the price.
3. Sow the seed — Sow into moisture in the cool part of the season, in rows, and expect a long slow rosette stage.
4. Water — Safflower is grown on stored moisture, and the water you must avoid is at the top and at the end.
5. Weeds and feeding — Weed during the rosette weeks while you still can, because afterwards the spines make it miserable work.
6. Flowering, and the weather that decides everything — The heads open over two or three weeks, and what the air does during those weeks is the whole crop.
7. Watch for trouble — Almost all serious safflower trouble is a fungus that arrives with damp air, and birds on the spineless kinds.
8. Harvest — Wait until the plant is dry and brown, because unlike most oilseeds this one holds its seed in the head.
9. Thresh, dry, store and sell — Thresh out the white seed, dry it properly and store it sealed, because safflower oil turns like any other.

Common Problems & Troubleshooting

If you see: Heads going brown and soft from the top down, with grey or dark mould in them, in the days after a humid or rainy spell while they were open.

It likely means: Head rot. Safflower flowers must have dry air, and damp weather while the heads are open is the single most destructive thing that happens to this crop.

Do this: Choose the sowing date so that flowering falls in a dry spell, which is the only real control.

If you see: A crop that had grown up and branched, blackened and collapsed after a cold night, although it stood through colder weather earlier in the season.

It likely means: Frost after the plant left the rosette stage. Safflower takes frost well while flat on the ground and very badly once it has shot up.

Do this: Time the sowing so that the plant shoots up after the last hard frosts rather than before them.

If you see: A crop that grew well early and then wilted and filled poorly through a dry finish, on ground where you expected the deep root to carry it.

It likely means: The taproot did not get down, usually because of a hard pan or genuinely shallow soil.

Do this: Dig a hole and look for a hard layer before choosing a field for safflower.

If you see: Heads stripped of seed on the standing crop, worst at the field edges, on a crop with soft spineless leaves and bracts.

It likely means: Birds. The spines on ordinary safflower keep them off, and a spineless kind has given that defence away in exchange for easier handling.

Do this: Grow spiny kinds where birds are a serious problem, and accept the harder handling.

If you see: Individual plants wilting and dying while their neighbours stand, with brown discoloured tissue inside when the stem base is cut across.

It likely means: A wilt disease living in the soil, which builds up where safflower or sunflower is grown too often.

Do this: Leave several years between safflower crops, and do not alternate it with sunflower.

If you see: Workers with scratched arms, hands and eyes after weeding or harvesting, and people unwilling to go back into the crop.

It likely means: The spines. Most safflower kinds are sharply spined on the leaves and around the heads, and dry plants at harvest are worse than green ones.

Do this: Do all hand weeding during the rosette stage, before the plant arms itself.

If you see: Stored seed or oil with a sharp bitter smell like paint, and a crusher who rejects the lot.

It likely means: The seed was stored damp or warm, or it was crushed or broken long before it was sold.

Do this: Dry until the seed cannot be dented with a fingernail before storing anything.

Yield & Market Value

Growing the crop is only part of the job. The last part is knowing what a normal harvest looks like where you are, and knowing what your seed is worth before you agree a price with anybody.

Remember It This Way

If you forget every other page of this guide, keep these lines. They are the whole crop, in order, short enough to carry in your head.

Deep soil and a broken pan, or the taproot cannot do its job.
Sow so that flowering lands in dry air. That is the whole crop.
The flat rosette is not a failure. It is the root going down.
Rosette takes frost. Once it shoots up, frost kills it.
Weed while it is still flat, before it grows its spines.
Long sleeves, gloves and eye protection after that.
Never wet the open heads. Overhead water means head rot.
It does not shatter. There is no reward for harvesting early.
Harvest dry and brown, in the middle of the day.
Winnow out the spiny chaff. That is what a crusher deducts for.

Test Yourself: Identification

What is this spiny plant with a bright orange thistle-like flower?

Where is the seed, if the flower is a head of many little flowers?

How do I know when the crop is ready to cut?

Honest Limits of This Guide

Timings are given in days and seasons rather than in months, because safflower is a winter crop in some countries and a spring crop in others. Your sowing date should be chosen backwards from when flowering will fall in dry weather.
Whether a spiny or a spineless kind is the better choice depends entirely on whether labour or birds is the bigger problem where you are, and this guide cannot decide that for you. It sets out both costs honestly instead.
Oil content and oil type requirements differ between crushers and countries, and this guide cannot tell you what yours will pay for. Ask before you deliver rather than after.

Sources

GBIF Backbone Taxonomy species-match record for Carthamus tinctorius L. — Global Biodiversity Information Facility (GBIF), Copenhagen (source)
World Flora Online name-matching record wfo-0000024004, Carthamus tinctorius L. — World Flora Online Consortium (source)
EPPO Global Database — Carthamus tinctorius (EPPO code CAUTI) — European and Mediterranean Plant Protection Organization (EPPO), Paris (source)
FAOSTAT crops and livestock products — production data for safflower seed — Food and Agriculture Organization of the United Nations (FAO), Rome (source)
Carthamus tinctorius (safflower) — CABI Compendium datasheet — CABI, Wallingford (source)

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