By: Liz Baessler
Growing cauliflower is not for the faint of heart. Keep reading to learn more about how to protect cauliflower plants, including cauliflower frost protection, sun protection, and pest protection.
Cauliflower is cold hardy, but it’s not invincible, especially when it’s young and tender, so some cauliflower frost protection is necessary in the spring. Start your cauliflower seeds indoors and transplant them outside around the time of the average last frost. If a later frost is likely, protect your young plants with row covers.
Likewise, cauliflower has just as hard a time with hot weather. If grown too late into the summer, the plants are likely to get leggy and bolt. Protect them by starting them early enough in the spring or close enough to autumn that they avoid the hottest days.
No matter when you grow them, you’ll want to protect your cauliflower heads from the rays of the sun. Once the white head is 2 to 3 inches (5 to 7.5 cm.) across, tie the leaves of the plant together so they shelter it. This is called blanching.
One of the most important aspects of cauliflower protection in gardens is cauliflower pest protection. Cauliflower can fall victim to a host of insect pests that include:
Again, as with cauliflower frost protection, row covers will help protect young plants from common pests like cabbage worms, root maggots and flea beetles.
Cabbage worms can also be picked off by hand, and aphids can be sprayed off with a stream of water followed by neem oil. Slugs and snails can be killed with bait.
Protecting cauliflower plants from pests is important – you’re very likely to get them, and they can wipe out a crop if you’re not careful.
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Read more about Cauliflower
Cauliflower is a sun-loving, cool-season crop to grow in spring and fall. It can be a temperamental plant in the garden because it does not tolerate heat or cold—so it’s not best for beginners unless you like a challenge! See how to plant, care for, and harvest cauliflower.
This vegetable’s name comes from the Latin words caulis, for cabbage, and floris, for flower. It’s a descendent of wild cabbage! Though usually white, cauliflower does come in other colors including purple, yellow, and orange.
Cauliflower can be a challenge for the beginner gardeners because it requires consistently cool temperatures with temperatures in the 60°Fs. Otherwise, it may prematurely “button”—form small, button-size heads—rather than forming a single, large head.
A frost occurs when the air temperature dips below 32˚F (0˚C) at ground level. A hard frost or freeze is a period of at least four consecutive hours of air temperatures that are below 28˚F (-2˚C).
Many plants can survive a brief frost, but very few can survive a hard freeze. Frost damage occurs when the liquid in the plants tissues freezes and bursts due to the cold temperatures.
Some plants have flexibility in their tissues and can withstand a certain amount internal ice formation without serious injury.
Vegetable garden crops that are most vulnerable to unexpected late spring frosts are young seedlings and the heat loving summer crops. Any plants that are specified on the seed package to be planted after all danger of frost is past are defenseless to an unexpected frost.
Frost tender plants include beans, corn, cucumbers, eggplants, melons, okra, peppers, squash, sweet potatoes, and tomatoes. These plants will be damaged or killed by frost if left unprotected.
Semi-hardy vegetables can survive light frosts that dip to 32˚F. These include artichokes, bok choy, Chinese cabbage, cauliflower, celery, collards, leaf lettuce, mustard, peas, potatoes, and radishes.
Established cold hardy plants can tolerate lower temperatures as low as 20˚F. However, new transplants and young seedlings may be vulnerable. These vegetables include arugula, broccoli, Brussels sprouts, beets, cabbage, carrots, kale, kohlrabi, leeks, onions, parsnips, radishes, rutabaga, spinach, Swiss chard, and turnip.
Cold air moves downslope and settles in the lowest spots . The cold spots in your yard are good choices for planting fruit trees that need chill hours and other cold-loving plants.
Plant frost-tender trees and plants in the warmest areas of your yard. An area with a western or southern exposure with reflected heat from a block wall will be warmer than other areas in your landscape. The heat absorbed by a block wall throughout the day will radiate during the night.
Cauliflowers aren't difficult to grow - but it can be a bit of a challenge to produce large. quality heads. Having said that, they are still worth a go. Growing single portion cauliflowers is often an easier, better bet - and certainly more suitable for individuals and small families.
There are also varieties that produce heads of a different colour to the standard white. These look very attractive and ornamental, so could be grown in flower beds and borders or in containers on the patio.
By growing different varieties you can have cauliflowers ready to harvest and eat for much of the year.
Cauliflowers prefer to be grown in an open, sunny position.
They need fertile, deep soil, that is preferably alkaline, with lots of added organic matter. If your soil is acidic, add garden lime before sowing or planting out.
The main sowing period is from March to May. You can sow earlier in mild regions under cloches, and later in June for late varieties. For a very early crop in late summer or early autumn, sow indoors in cell trays in a heated propagator or on a windowsill in late January/February.
For best results, sow seeds very thinly in a separate seedbed in a shallow drill about 13mm (½in) deep. Cover with soil and water in well.
When the young plants have 5 or 6 leaves, carefully lift and transplant them to their final growing position. Improve the soil first with a general granular plant feed. Firm the soil around each plant afterwards and water in well. Space summer and autumn cropping cauliflowers 60cm (2ft) apart and winter cropping ones 75cm (30cm) apart. For small, individual portion cauliflowers, space plants 15-23cm (6-9in) apart.
Water plants well in dry weather and covers the soil with a mulch to conserve soil moisture. Occasional feeds with a liquid feed through summer will improve the crop. The curds of summer cropping varieties need protection from strong, burning sunlight - simply bend a few of the larger, upper leaves over them. Doing this in late autumn and winter will protect against frost damage.
Start to harvest by cutting through the main stem under the head when it is a good size and still firm. If you leave it too late the individual florets in the head will start to separate this not only looks less attractive but it also reduces the flavour.
Cauliflowers may be susceptible to the following pests and diseases.
Growing your own cauliflower can be a challenge, but by planting your crop in containers, you make it easier to control their growing environment.
Keep your plants happy and healthy and you have a good chance of finding a beautiful head waiting for you under the leaves at harvest time.
Just remember: water, water, water. If you keep the soil moist but not waterlogged, you’ve already won half the battle.
Have you grown cauliflower in containers and do you have any tips to share? Let us know in the comments below!
And for more information about growing cauliflower, check out these guides next:
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Kristine Lofgren is a writer, photographer, reader, and gardening lover from outside Portland, Oregon. She was raised in the Utah desert, and made her way to the rainforests of the Pacific Northwest with her husband and two dogs in 2018. Her passion is focused these days on growing ornamental edibles, and foraging for food in the urban and suburban landscape.