Cauliflowers

Cauliflower is a cool-season vegetable in the cabbage family, grown for its firm, rounded head called a curd. Most cauliflower is white, but it also comes in orange, purple and green, and it can be eaten raw, roasted, steamed or even mashed.

Cauliflower Quick Facts

Common name	Cauliflower
Scientific name	Brassica oleracea
Kingdom	Plantae
Phylum	Tracheophyta
Class	Magnoliopsida
Order	Brassicales
Family	Brassicaceae
Genus	Brassica
Conservation status	Data Deficient
Type	Cool-season vegetable in the cole family
Habitat	Full sun, fertile moist soil with pH 6.5-6.8
Size	Heads 6 to 12 inches across
Colours	White heads; orange types exist
Edible parts	The firm flower head (curd)
Special feature	Outer leaves are tied to keep the head white

Anatomy

Cauliflower belongs to the species Brassica oleracea, the same species as broccoli, cabbage, kale and collards. The white head we eat is made of thousands of tightly packed, undeveloped flower buds and short, thick stems. If the plant is left alone, the head eventually loosens and grows into tall stalks of small yellow flowers.

Large green leaves wrap around the curd, helping to shade and protect it as it grows.

Where Cauliflower Grows Best

The secret to growing cauliflower is keeping it cool. It grows best when temperatures are around 60 to 70 degrees F (16 to 21 C). Too much heat or cold can stop the head from forming properly.

That is why much of the cauliflower sold in the United States comes from the mild coast of California, where cool sea breezes keep conditions just right for many months of the year.

Growing Cauliflower at Home

Cauliflower is one of the fussier vegetables to grow, but with steady care it is very rewarding.

Soil and Sun

Plant cauliflower where it gets at least six hours of sun a day. It needs fertile, moist, well-drained soil full of organic matter, with a pH of about 6.5 to 7.0. Testing your soil is a good idea. A slightly higher pH helps prevent clubroot, a disease that swells and damages roots. Add lime only if a soil test says you need it.

Cauliflower is a hungry plant. Before planting, mix in compost and a nitrogen-rich fertilizer or a slow-release vegetable fertilizer.

Planting

Start seeds indoors about 4 to 5 weeks before you plan to plant them outside. Sow them 1/4 to 1/2 inch deep and keep the soil moist. When the seedlings have a few true leaves, harden them off for about a week, then move them to the garden.

For a spring crop, plant out around two weeks before the last frost, and cover young plants with cloches, such as cut-off milk jugs, if a hard frost threatens. For a fall crop, plant in mid to late summer and give young plants some shade and plenty of water during hot spells.

Space plants about 18 inches apart in rows about 30 inches apart, leaving room to walk between them.

Watering

Give cauliflower about 1 to 1.5 inches of water each week, enough to soak the soil about 6 inches deep. A layer of mulch keeps the soil cool, holds in moisture and blocks weeds.

Steady growth is the key. If plants are stressed by drought, heat, cold or crowding, they may form tiny, early heads called “buttons,” or their curds may turn grainy and loose, a problem gardeners call “ricing.”

Blanching for White Heads

When the curd is about 2 to 3 inches across, many gardeners blanch it. Gently pull the large outer leaves up over the head and tie them loosely with twine or a rubber band. This shades the curd from the sun so it stays white and mild. Many newer varieties are “self-blanching,” with leaves that curl over the head naturally. Colored varieties do not need blanching.

Pests and Problems

Flea beetles chew tiny holes in young leaves, especially in spring. Aphids suck sap from leaves. Cabbage root maggots tunnel into roots, while imported cabbageworms and cabbage loopers munch on leaves. Floating row covers put on right after planting help keep many of these pests away.

Cauliflower also needs the nutrient boron. If the soil is short of it, the curd can turn brown and the stems may become hollow. A soil test and advice from a local garden center or extension office can help fix the problem.

Harvest and Storage

Most heads are ready about one to two weeks after blanching. Harvest when the curd is firm, tight and about 6 to 8 inches across, before the buds start to separate. Cut the stem just below the head with a sharp knife, leaving a few leaves attached to protect it.

Store cauliflower in a plastic bag in the refrigerator for about a week. For longer storage, cut it into florets, blanch them briefly in boiling water, cool them and freeze them. Cauliflower can also be pickled.

Varieties

• Snowball: A classic white variety with medium heads that grows well through much of the season.
• Orange cauliflower: Tastes much like white cauliflower but contains beta-carotene, which the body turns into vitamin A.
• Purple cauliflower: Colored by the same natural pigments found in red cabbage. The color may fade a little when cooked.
• Green cauliflower and Romanesco: Lime-green types, with Romanesco forming amazing spiral-shaped points.

Whatever the color, cauliflower is high in vitamin C and fiber, making it a healthy addition to many meals.

Cauliflower FAQs