How to Grow and Care for Cauliflower

Follow our tips for growing this sometimes difficult cool-season vegetable.

Reviewed by Julie Thompson-Adolf

Cauliflower (Brassica oleracea, Botrytis group) is one of the many cabbage-related cole crops that revel in cool weather. It has thick, oval leaves with pronounced midribs and veins. The leaves and stem of cauliflower are both edible. The cauliflower head, the main edible part of the plant, is composed of tightly packed undeveloped flower buds, often referred to as curds. Cauliflower has a very distinct nuttiness and is similar to broccoli in flavor. It is not the easiest vegetable to grow because it is very sensitive to temperature changes and susceptible to pests and diseases. All varieties, but especially white cauliflower, need to be blanched, by covering the head with its leaves.

Plant cauliflower in early spring for an early summer harvest or in midsummer for a fall harvest. It has a moderately slow growth rate and is ready to harvest in two to three months after planting, depending on the type.

How to Plant Cauliflower

When to Plant

For a summer harvest, plant cauliflower seedlings about two weeks before the last average frost date in the spring. It is best to plant the seedlings when they are not older than four to five weeks, as more mature seedlings tend to have difficulties getting established. Make sure to harden off your transplants before setting them out in the garden.

Gardeners in cold climates often have better luck putting out transplants in mid- to late summer for a fall harvest.

In frost-free or almost frost-free climates, you can also plant cauliflower in the fall, from September onwards all the way through February, for a winter harvest.

Selecting a Planting Site

Choose a location in full sun or with some afternoon shade. The soil should be rich, fertile, and well-draining. Following crop rotation rules, do not plant in the same spot where other members of the cole crop family were grown in the past two years, preferably longer.

Spacing, Depth, and Support

Plant cauliflower seedlings 18 to 20 inches apart in rows 2 to 3 feet apart.

Cauliflower Care

Light

Cauliflower plants need full sun, although a little partial afternoon shade in hot climates help prevent sun scorch.

Blanching Cauliflower

Cauliflower needs to be blanched to avoid discoloration, especially white varieties. The flavor isn't terribly altered if you allow it to turn its natural yellowish-brown, but it does seem to remain a little sweeter and a lot more appealing if blanched. Begin blanching the heads when they are about the size of a large egg. Start the process when the plants are fully dry, to prevent rotting. The traditional way to blanch is to fold some of the larger leaves over the head and tuck or secure them on the other side. Hold them in place with a clothespin, rubber band or string. Don't fit the leaves too tightly; block the light but leave room for the head to expand. Once the leaves are in place, try not to get them wet and check under them periodically to make sure insects aren't using them as a hideout.

Soil

Cauliflower needs a soil rich in organic matter, with a soil pH between 6.5 and 7.5. Excellent drainage is key.

Water

Cauliflower needs consistent moisture and plenty of it. Without sufficient water, the heads will be stunted and turn bitter. Provide at least 1 to 2 inches of water per week, and make sure it is soaking 6 to 8 inches into the soil. Lack of moisture in dry weather will cause the buds to open slightly, turning the heads grainy or ricey rather than forming tight curds. Insufficient water also causes malformed, very small flower heads instead of a single large head, a defect called buttoning.

Temperature and Humidity

Cauliflower likes cool weather but is sensitive to frost. It begins to suffer in temperatures above 80 degrees F, which is why it's typically planted in spring or fall and harvested before or after the hottest days of summer. Mulch the plants at planting time to keep the soil cool and help retain moisture.?

Fertilizer

Cauliflower is a heavy feeder. Fertilize it every two to four weeks with an organic all-purpose fertilizer for vegetables, or use kelp or fish emulsion. Organic fertilizers are preferable because they won’t cause nitrogen burn.

Boron deficiency in the soil can cause hollow stems and discolored and deformed curds. If you have tried to grow cauliflower and had this problem, get your garden soil tested by a specialized laboratory (local Extension Offices offer inexpensive soil test kits) and follow the recommendations for a boron fertilizer in the soil test report.

Types of Cauliflower

In view of the large number of cauliflower varieties available from seed companies, finding the best cauliflower variety to grow in your garden may seem a bit overwhelming. Since cauliflower does not form heads in warm weather and handles only a light frost, be sure to choose a variety that will have enough time to mature. Varieties with a shorter growth cycle and good heat tolerance are usually best for spring planting whereas varieties with more days to maturity and better cold tolerance are preferred for fall harvest. Also, do some sleuthing at your local cooperative extension office to find varieties that do especially well in your area.

• ‘Snow Crown’: Hybrid with unusual seedling vigor, suitable for summer or fall harvest and good tolerance to moderate fall frost; matures in 50 to 55 days.

• ‘Amazing’: An open-pollinated white variety for late summer and fall planting that produces large, self-blanching heads. Good tolerance both to heat and cold; matures in 75 days.

• ‘Denali’: Hybrid with large white, self-wrapping heads. Good heat resistance makes it suitable for summer sowing and fall harvest or fall and winter in mild climates; matures in 73 days.

• ‘Green Goddess’: Lime green hybrid with a domed head; no blanching required; matures in 60 to 65 days.

• ‘Purple Moon’: Hybrid with medium-size purple heads that do well in hot weather and are also suitable for fall harvest; matures in 62 days

• ‘Cheddar’: Hybrid with pretty orange heads that are slow to bolt; best for fall harvest; matures in 55 to 60 days.

Standard White vs. Colored Cauliflower

Orange cauliflowers have been bred from a genetic mutation that was discovered in 1970. The orange coloring comes from beta-carotene, the same source of orange in carrots. It's not a GMO, just the result of a fluke mutation that has been used to make hybrid varieties.

Purple cauliflowers have been around for generations. There are several heirloom varieties, such as the popular 'Purple of Sicily', and some recent hybrids. They all get their purple color from the antioxidant anthocyanin, as does red cabbage, red grapes, and red wine. Unfortunately, most
purple vegetables lose their color when cooked, and purple cauliflower is not
?an exception. Enjoy it raw for the best benefits.

Whether Romanesco is a broccoli or a cauliflower is still the subject of debate among horticulturalists. What is beyond doubt, however, is that it is a striking vegetable with a wonderful nutty texture and flavor.

Harvesting

Cauliflower takes two to three months to mature. Harvest when the heads reach the desired size and while the buds are still tight.

Don't delay harvesting for too long, or the plants may bolt. It is better to harvest the cauliflower when mature and freeze it for later use. Another traditional storage method is to lift the whole plant, shake off the soil, and hang it up with the roots and stem intact in a cool, dry, well-ventilated place away from too much light. To prevent the plants from drying out, mist them lightly every day. Stored this way, cauliflower keeps for up to a month.

How to Grow Cauliflower in Pots

Cauliflower is suitable to be grown in containers. For each seedling, use a pot that is at least 12 inches wide and deep and has large drainage holes. Fill the pot with well-draining potting mix. Place the pots in a location with afternoon shade. Cauliflower does not like extreme heat, and potted plants are especially exposed. Water the plants regularly to keep the soil evenly moist, in hot summer weather this might require daily watering. The frequent watering washes nutrients away so increase the fertilizer frequency too, feeding the plant every two weeks with a fertilizer diluted to half strength.

As cauliflower is grown as an annual, it won’t need repotting.

Pruning

Remove any yellow or spotted leaves promptly to prevent the spread of diseases.

How to Grow Cauliflower from Seed

Cauliflower is propagated from seed. Starting your own plants from seed gives you more choices than what your local nursery or garden center carries. It also lets you pick the variety that fits your growing conditions and desired harvest time.

1. For spring planting, start the seeds indoors about four to six weeks before your area's average last frost date. Cauliflower doesn't like having its roots disturbed, so biodegradable pots are recommended.

2. Plant the seeds about 1/2 inch deep in potting mix and keep the soil evenly moist at all times. The ideal soil germination temperature is 70 degrees F, which might require a heat mat if the room is cool.

3. After the seeds have germinated, keep the seedlings at a temperature of around 60 degrees F.

To direct seed cauliflower, sow 3 to 4 seeds, 1/2 inch deep and 18 inches apart, in rows 24 to 36 inches apart. Water regularly to keep the soil evenly moist. Thin the seedlings 18 to 20 apart,

Common Pests and Plant Diseases

Unfortunately, cauliflower is susceptible to all the usual cole crop pests, and there are many, including cabbage maggots, cabbage loopers, and cabbage worms. Row covers offer good protection against cabbage moth butterflies, which lay eggs on the plants. Young transplants are also attractive to aphids and flea beetles, especially if grown in the spring. Groundhogs are exceptionally fond of cole crops. Fencing or caging is the best deterrent against rodents.

Cole crops are also problem-prone when it comes to diseases, with blackleg, black rot, and club root leading the pack. It's very important not to plant cole crops in the same place, year after year, and to clean up all debris at the end of the season, to prevent diseases from overwintering in the soil.

Frequently Asked Questions

Why is my cauliflower flowering?

Cauliflower naturally only flowers in its second year, which is a stage the plants usually never reach because the heads are harvested after one growing season and the plant is discarded afterward. Under heat stress, however, cauliflower may start to flower already in its first year, a process called bolting. Unfortunately, there is nothing you can do to stop it and rescue the plant.

How long does it take cauliflower to grow?

There are some early-maturing varieties such as EarliSnow which matures in 45 days; varieties for fall harvest such as Skywalker may take up to 80 days, The variety is not the only variable; the weather conditions also play into the length of time it takes for cauliflower to grow.

How many heads of cauliflower does one plant produce?

Unlike broccoli, cauliflower only produces one compact head called a curd. The average head of cauliflower is 6 to 7 inches in diameter and weighs about 2 pounds but some varieties grow larger heads than others. Unfavorable dry and hot conditions lead to stunted head growth and other problems.

Read the original article on The Spruce.