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Cauliflower

When to Plant

  • Plant a fall crop 6 to 8 weeks before the first fall frost date but after daytime temperatures are regularly below 75°F. Shade plants from heat, if necessary.

Choosing a Planting Site

  • Soil needs to be very rich in organic matter; mix aged manure and/or compost in the bed.

  • Cauliflower also needs extra nutrients. Apply 5-10-10 fertilizer. Fertile soil holds in moisture to prevent heads from "buttoning."

  • In early spring, be ready to protect plants from frost by covering them with old milk jugs, if necessary. Extreme cold can halt growth and/or form buttons.

  • Add mulch to conserve moisture.

How to Plant

  • It is best to start cauliflower from small nursery plants versus sowing seeds.

    • If you seed, start 4 to 5 weeks before the last spring frost date. Sow in rows 3 to 6 inches apart and up to 1/2 of an inch deep. Water consistently during germination and growth.

  • Transplant seedlings (or small nursery plants) 2 to 4 weeks before the last spring frost date, no sooner and not much later.

  • Set plants 18 to 24 inches apart with 30 inches between rows.

How to Grow

  • Cauliflower dislikes any interruption to its growth. Change, in the form of temperature, moisture, soil nutrition, or insects, can cause the plants to develop a head prematurely or ruin an existing one.

  • Water regularly with 2 inches of water each week; even with normal rainfall, this usually requires supplemental watering.

  • For best growth, side-dress the plants with a high-nitrogen fertilizer 3 t o 4 weeks after transplanting.

  • Note that the cauliflower will start out as a loose head and that it takes time for the head to fully form. Many varieties take at least 75 to 85 days from transplant. Be patient!

  • When the curd (the white head) is 2 to 3 inches in diameter, blanch it: Tie the outer leaves together over the head and secure with a rubber band, tape, or twine to keep light out. (This is not necessary for self-blanching or colored varieties). The plants are usually ready for harvest 7 to 12 days after blanching.

  • Brown heads indicate a boron deficiency in the soil. Drench with 1 tablespoon of borax in 1 gallon of water. (Avoid getting boron on other plants.) Or, provide liquid seaweed extract immediately; repeat every 2 weeks until symptoms disappear. In the future, add more compost to the soil.

  • For white varieties, pink heds can indicate too much sun exposure or temperature fluctuations. Purple hues can be due to stress or low soil fertility.

Pests/Diseases

  • Aphids

  • Black rot

  • Caggage loopers

  • Cabbage root maggots

  • Cabbageworm: Nectar from dwarf zinnias lures in ladybugs and other predators that help to protect cauliflower from cabbageworms.

  • Clubroot

  • Powdery mildew

  • Stinkbugs

  • Thrips

  • White Rust 

How to Harvest

  • Plants are usually ready to harvest in about 50 to 100 days, depending on variety, or 7 to 12 days after blanching.

  • When the heads are compact, white, and firm, then it is time to harvest them. Ideally, the heads will grow to 6 to 8 inches in diameter.

  • Cut the heads off the plant with a large knife. Be sure to leave some of the leaves around the head to keep it protected.

  • If the heads are too small, but have already started to open up, they will not improve and should be harvested immediately.

  • If the cauliflower has a coarse appearance, it is past maturity and should be tossed.