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Cauliflower Seed Starting Tips

Cauliflower seedlings

Cauliflower is a cool-season crop. Cauliflower thrives in temperatures between 57°F and 68°F (14°C-20°C).

Set cauliflower seedlings in the garden about two or three weeks before the average last frost date, not earlier. Sow cauliflower seeds indoors 4 to 6 weeks before setting seedlings in the garden. Cauliflower grows best at 57° to 68°F (14°-20°C).

Time cauliflower planting so that plants do not mature in hot, head-stunting summer weather. If summers are hot in your area, you may want to grow cauliflower in autumn. Set cauliflower seedlings out in June or July for September to November harvest.

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Transplant cauliflower seedlings into the garden when they are 6 to 7 inches (15-18cm) tall. Be sure to firm the soil well over seedling roots. Water seedlings daily for several days after moving them and protect them from direct sun until they are well-rooted.

For the best heads, cauliflower should grow rapidly. Plant in humus-rich soil and keep the soil evenly moist; do not let it go dry. When the head develops, break off a bottom leaf and set it over the curd (the developing head) to keep out the light.

Cauliflower seedlings
Cauliflower seedlings

Plant fast-maturing cauliflower varieties in spring or fall. Any variety that requires more than 80 days to mature should be planted for fall harvest. Purple varieties are both heat and cold-tolerant.

Cauliflower matures in 50 to 85 days depending on the variety.

Cauliflower planting details

  • Sowing depth: ¼ inch (6mm)
  • Space between plant after thinning: 20-24 inches (50-61cm)
  • Days to sprout: 8
  • Days to harvest: 50-85
  • Storage period: 2-3 weeks
  • Seeds per 100-row feet: 1 packet
  • Yield per 100-row feet: 60 heads
  • Early to harvest varieties (50-60 days): Extra Early Snowball, Super Snowball
  • Late-to-harvest varieties (80-110 days): Snowball Y, Snowball No. 84, Perfected Snowball, Snowball 57, Boomerang

Cauliflower sowing and planting tips

  • Start cauliflower from seed or transplants.
  • Seed is viable for 4 years.
  • Start seeds indoors 6 to 4 weeks before the last frost or 12 to 10 weeks before the first frost for a fall crop.
  • Seedlings started indoors can be planted out 2 to 3 weeks before the last frost.
  • Sow outdoors from the last frost to early spring for late spring or early summer harvest or in summer 12 weeks before the first frost for a fall crop.
  • Start seeds in individual pots or flats.
  • Sow seed ¼ to ½ (6-8 mm) inches deep in the seed-starting mix.
  • Keep the mix moist but not wet.
  • Seeds should germinate in 6 days at an optimal temperature of 70°F (21°C) or thereabouts.
  • Transplant seedlings into the garden when they are 4 to 6 inches (10-15 cm) tall with 2- to 4-leaves and daytime temperatures reach 50°F (10°C); firm transplants into the soil by hand.
  • Cauliflower prefers a soil pH range of 6.0 to 7.5.
  • Grow cauliflower in full sun for best yield—plants tolerate partial shade.
  • Add 3- to 4- inches of compost and well-aged manure into the planting bed, before transplanting; cauliflower needs friable, moisture-holding soil.
  • Avoid planting cauliflower where cabbage family crops have grown recently.
  • Space plants 15 inches (38 cm) apart.
  • Space rows 20-24 inches apart.
  • Protect the seedlings from the cold for 2 to 3 weeks after planting covering them with a cloche or plastic tunnel or cold frame.
  • Keep soil moist after transplanting seedlings; this will ensure rapid growth.
  • Feed with an organic fertilizer such as fish emulsion at half strength; be sure cauliflower gets potassium, phosphorus, and magnesium.
  • Common pest enemies are aphids, flea beetles, cabbage worms and loopers, cabbage worms, and cutworms.
Planting cauliflower seedlings plant grow cauliflower
Planting cauliflower seedlings

 Cauliflower planting calendar

Planting for late spring harvest:

  • 6-10 weeks before the last frost in spring: start seed indoors.
  • 4-6 weeks before the last frost in spring: transplant seedlings under a plastic tunnel or cold frame
  • 3-4 weeks before the last frost in spring set transplants out in the open garden.
  • 2-3 weeks before the last frost in spring: direct-sow in the garden; protect emerging seedlings from the chill with a spun poly row cover; minimum soil temperature should be at least 40°F.

Planting for fall harvest:

  • 10-12 weeks before the first frost in fall: start seeds indoors.
  • 8-10 weeks before the first frost in fall: transplant seedlings into the garden for fall harvest.
  • 6-8 weeks before the first frost in fall: transplant seedlings into the garden for late fall harvest; protect plants from frost under spun poly floating row covers.

Cauliflower seedling planting dates for spring and summer harvest

(These dates are for the Northern Hemisphere)

Average date of the last frostPlanting dates
Jan. 30Jan.1-Feb. 1
Feb. 8Jan.1-Feb. 1
Feb. 18Jan.10-Feb. 10
Feb. 28Jan.20-Feb. 20
Mar. 10Feb. 1-Mar. 1
Mar. 20Feb. 10-Mar. 10
Mar. 30Feb. 20-Mar. 20
Apr. 10Mar. 1-Mar. 20
Apr. 20Mar. 15-Apr. 20
Apr. 30Apr. 10-May 10
May 10Apr. 15-May 15
May 20May 10-June 15
May 30May 20-June 1
June 10June 1-June 15
Cauliflower plant
Cauliflower Seed Starting: Time the planting of cauliflower so the crop does not mature in hot weather; hot weather will stunt heads. For a fall crop, sow seed in early- to mid-summer.
  • ‘Early Snowball’, small, quick maturing.
  • ‘Amazing’ self-blanching.
  • ‘Fremont’ self-blanching.
  • ‘Snow Crown’ tolerates frost to 25°F.
  • ‘Graffiti’ bright purple heads.
  • ‘Violet Queen’ purple head.
  • ‘Alverda’ and ‘Panther’ green heads.

Interplanting: Interplant with beets, green onions, spinach, and herbs.

Container Growing Cauliflower: Choose a container with a minimum depth of 20 inches (51 cm).

Botanical Name: Brassica oleracea var. botrytis

Cauliflower is a member of the Brassicacea (Cruciferae) or cabbage family.

More tips: How to Grow Cauliflower

Garden Planning Books at Amazon:

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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