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Cauliflower Growing and Harvest Information

by chuck.mcmullan

Cauliflower is an annual cool-season crop, half-hardy to frost and light freezes. To prevent spreading clubroot and other soil-borne diseases, don’t compost any brassica roots. Pull and destroy all infected plants. Also rotate brassica plants on at least a 3-year basis, preferably on a 7-year basis.

Where to Grow Cauliflower

Cauliflower can be grown wherever there are steady cool, frost-free growing seasons. It is a little more particular than other brassicas and around 60 degrees is the preferred temperature.

Recommended Varieties of Cauliflower

Early Snowball; Snowball Imperial; Self-Blanch (fall); and Early Purple-Head (fall, not blanched).

Soil for Cauliflower

Fertile, enriched loam is ideal with pH from 6 to 7. Cauliflower is sensitive to boron deficiency in the soil.

Planting Cauliflower

Germination 3-10 days.

When –

Cauliflower can be difficult to grow as a spring crop because it tends to bolt in the heat. It is generally easier to grow as a fall crop for this reason. It is the most sensitive of the brassicas to frost. Cauliflower should not be transplanted outdoors until all danger of frost is past, unless covered. It also needs to mature before the hot summer weather arrives. A compromise might be to choose an intermediate starting date and cover the plants when set out to protect them from the cold. For fall crop, start seed in mid-June to set out transplants in late July. Allow 2 to 3 months growing time before first frost.

How –

In rows 2 1/2 to 3 feet apart, with 2 feet between plants. Plant transplants 1″ deeper than they were grown in starting pots, and cover with netting to protect from pests.

Germination45 - 85F
For growth60 - 70F (Daytime)
50 -60 F (Nighttime)
Soil and Water
FertilizerHeavy feeder; needs high N and K.
Side-dressingevery 3-4 weeks
pH6.0 - 7.5
WaterAverage need although it is critical early in season, and during warm weather.
Seed Planting Depth1/4 - 1/2"
Root Depth18 - 48'
Height18 - 24"
Width24 - 30"
Space between plants
In Beds12 - 15"
In Rows18"
Space Between Rows24 - 46"
Average plants per person3 - 5
When heads are 8-10" in diameter, harvest by pulling the entire plant from the soil. Cauliflower heads deteriorate quickly, so check periodically and harvest when ready.
First Seed Starting Date: 25-45 days (uncovered)
53-73 (covered)
before last frost date
Last Seed Starting Date: 89 - 140 Days before first frost date
CompanionsAromatic plants, artichoke, beet, bush beans, garlic, lettuce, peas, potato, spinach.
IncompatiblesPole beans, strawberry, tomato, kohlrabi

How Cauliflower Grows

The plant has broad green-blue foliage that develops a central flower head. This increases in size to a large, cabbage-sized head of condensed flowers. By tradition, the head is blanched (covered from the sun) to bleach it white. Spacing between plants determines head size: the closer together, the smaller the head. When heads start forming, prevent yellowing by tying several upright leaves loosely together with string, covering the rest of the head from direct exposure to sunlight.

Storage Requirements
Wrap individual plants, head and roots, in plastic. Store in a root cellar or cool place.
TemperatureHumidityStorage Life
32 F95 - 98%3 - 4 weeks
MethodTasteShelf Life
FrozenGood12 months
DriedGood12 months

Cultivating Cauliflower

The trick to cauliflower is to keep it growing steadily once the seedlings are planted outdoors. So much, however, depends on proper growing weather – ideally, a cool, long, sunny season with ample moisture or irrigation. When the center begins to develop a tight flower head about the size of a McIntosh apple, loosely tie the outer leaves with twine. Do not tie too tightly, as there must be some air circulation. This will cause the flower head to bleach white in about 1 to 2 weeks.

Harvesting Cauliflower

Cauliflower is ready to harvest in approximately 60-80 days from transplant date. As soon as the compact head is formed and blanched, it should be cut off with a sharp knife, along with several of the leaves for protection. The head should look full, and will likely be slightly smaller than supermarket varieties. Harvest when the curds of the head are still smooth. If too many heads ripen at once, cut them anyway and store them in a cool, dark place for several weeks. Ripened heads left on the plant will rot and deteriorate rapidly.

Cauliflower Pests

  • Same as cabbage
  • Root Maggot -Place 3-inch tar paper squares around each seedling when transplanting to cover the soil areas; or keep the ground dusted with wood ash.
  • Cabbage butterflies/worms -controlling cabbage worms is surprisingly easy.  Cover susceptible crops with a floating row cover when planting and leave it in place until harvest.
  • Cutworms – Use stiff paper collars around transplants to extend at least 1 inch below the soil line.
  • Flea beetles – Dust with wood ash or flour dust.

Diseases for Cauliflower

  • Same for cabbage
  • Soil fungicides are somewhat effective on cauliflower diseases, but they are expensive, sold in large quantity, and not practical for small home garden use, unless a great deal of cauliflower is grown.
  • Clubroot fungus – Most frequent in soggy or acid soil. Grow only in well-drained soil; follow crop rotation practices; lime to keep soil pH at a neutral 7.
  • Yellows – A soil-borne diseases; choose resistant varieties.
  • Black rot – Bacteria born on seed; buy only from reputable seed dealers or bedding plant growers; rotate crops.
  • Blackleg – Bacteria spreads from infected plants, garden tools, and leftover debris. Follow crop rotation.

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