key growing information

Cauliflower Growing Information: How to Plant, Grow & Harvest

How to grow cauliflower from seed: soil and moisture, spring, fall and winter schedules, transplant age, blanching white heads, pest and disease prevention, harvest and storage.

By Hensley’s Seed Co. September 3, 2026

Cauliflower - Key Growing Information

Cauliflower plant leaves, tied for blanching the head of a white cauliflower cultivar.

SCIENTIFIC NAME:

Brassica oleracea

CULTURE:

Cauliflower needs fertile, well-drained soil rich in organic matter, a pH of 6.0–7.5, and steady moisture all season, so water regularly. It struggles in hot weather; spring and fall crops are the most reliable.DAYS TO MATURITY: Counted from transplanting.

TRANSPLANTING:

Spring crop: choose early and midseason varieties and sow in 72-cell plug flats. Transplants are usually ready in 4–6 weeks. If you can, keep the soil at 70°F (21°C) or warmer until seedlings emerge, then about 60°F (16°C). Set plants out by the time they are 4–5 weeks old; older transplants are often stressed and don't perform as well as young, actively growing ones. Harden them off gradually with cooler conditions, then plant 18" apart in rows 24–36" apart. Fall crop: Grow midseason and storage varieties, starting seedlings the same way in May and planting them out in June or July. Where hard freezes come early in fall, sow early enough for heads to mature. Winter crop: in mild-winter areas where temperatures seldom drop below 32°F (0°C), cauliflower can be grown through winter, with transplants set out from September through February.

DIRECT SEEDING:

Plant ½" deep in groups of 3–4 seeds every 18", rows 24–36" apart, and thin each group to the strongest seedling.

BLANCHING:

Sunlight can turn white heads yellowish. To keep curds white and improve quality in warm weather, blanch them: as soon as small white heads become visible through the leaves, pull the outer leaves up over the head and secure them with string or a wide rubber band. Alternatively, snap the midribs of a few leaves and fold them down over the head until it's fully covered, taking care not to tear them off, or they may blow away. Covered heads stay more humid, which raises the risk of Alternaria, so blanch only when it's needed. Skip it in the cool, short days of fall and with colored varieties, which need sun to develop full color.

INSECT PESTS:

Covering young plants with floating row covers right after planting keeps flea beetles and root maggots away. If flea beetle pressure gets heavy, use insecticides such as pyrethrin or azadirachtin. Bacillus thuringiensis (Bt) controls cabbage worms and loopers. To head off cutworms, till the soil 2–4 weeks before planting to incorporate cover crops and kill weeds.

DISEASE:

Prevention is the best approach: (1) rotate with non-brassica crops for several years, (2) use clean seed-starting mix and seedbeds, and (3) keep tools and fields clean. Select cauliflower seed lots that tested negative for black rot (Xanthomonas campestris pv. campestris) and black leg (Phoma lingam). Keep in mind that a negative test only means the pathogen wasn't detected in the sample examined; it is not a guarantee the whole lot is disease-free, and no seed treatment can promise that either. Feel free to contact us with specific questions.

HARVEST:

Check heads often and cut them once they reach the size you want, before the curd starts to loosen or turn grainy ("ricey").

STORAGE:

Keeps 2–3 weeks at 32°F (0°C) and 95–98% relative humidity.

SIZED SEEDS:

Sized seed has been graded to a uniform size, which gives more precise spacing in mechanical seeders and a more even stand. Our cauliflower seed is sized unless the product description says otherwise.

SEEDS/LB.:

84,000–164,400 (average 105,800).

PACKET:

100 seeds per packet unless noted.