Cauliflower is a nutritious, versatile vegetable that offers so many possibilities in the kitchen and is satisfying to grow. If you want to grow cauliflower in your garden, here’s everything you need to know to keep it thriving from planting to harvest.
You can also download my How Do I Grow Cauliflower? one-sheet and keep the free resource handy for your reference.
Cauliflower is a cole crop — a cultivar of wild cabbage, just like broccoli, Brussels sprouts, kale, collards, kohlrabi and, yes, cabbage. Also known as brassicas, they are a cold-hardy group of vegetables.
Cauliflower has a reputation for being fussy, but despite its quirks, it’s definitely a crop worth growing. You’ll enjoy cauliflower’s great taste and can also revel in the thrill of successfully growing it to harvest.
Raw cauliflower is great for dipping. When cooking cauliflower, you can’t go wrong by roasting it, and there are countless ways to season it. You can also steam or saute cauliflower, or include it in curry. In recent years, cauliflower has grown in popularity as a replacement for other ingredients, such as riced cauliflower instead of white rice. Buffalo cauliflower replaces buffalo boneless wings, and cauliflower crust replaces traditional pizza crust.
Where, When and How to Plant Cauliflower
Cauliflower is one of those crops for which the importance of getting a soil test is especially true. Cauliflower requires a soil pH of between 6.5 to 7.5 to discourage a disease known as clubroot. And if you find your soil falls outside of that range, the soil test results will tell you what to do to bring it in line.
When planning on growing cauliflower, don’t delay. You should start as early as possible to ensure it matures before the heat of summer sets in. Heat will cause cauliflower to bolt, which means the plant has focused its energies on seed production. Bolted cauliflower has a bitter taste and should be pulled and composted.
You can start cauliflower seeds indoors in sterile seed-starting mix under grow lights about four to five weeks before the last frost or sow directly outdoors after that. Cauliflower will germinate best in soil that is 80° so use a seed-starting heating mat if working indoors. Outdoors, seeds will sprout in soil temperatures as low as 50°. Germination will occur after eight to 10 days.
Or simply purchase pre-started seedlings and plant them in spring about the time of the last frost. Just be sure seedlings have a chance to gradually adjust to the outdoor light and climate (a process known as hardening off) for at least a week before planting out. And space your plants in the ground about 18 inches apart and 30 inches between rows.
Cauliflower is a heavy feeder that requires full sun (at least six hours of direct sunlight per day) and fertile, well-drained soil. Prior to planting, amend the planting bed with plenty of compost to improve fertility and drainage.
Shielding cauliflower with row cover as soon as it is planted will save a lot of trouble later. Cauliflower is a magnet for brassica pests, but row cover will prevent many insects from ever laying their eggs on or near your plants.
In the North, you can plant a second crop of cauliflower in July for a fall harvest. Get seeds or transplants in the ground eight weeks before the average first frost date for your area. If daytime temperatures are still 75° or warmer, give the seedlings some protection by covering them with shade cloth.
Cauliflower traditionally has a white head but these days you can also find yellow, green, purple and even orange. Choose a variety that is suited to your growing region to give your crop the best opportunity for success.
Amazing is an open-pollinated white cauliflower that is self-blanching and tolerant of both heat and cold. Self-blanching means the leaves wrap around the head to protect it from an abundance of sun. It matures in 68 days.
Andes is a white cauliflower that is both heat and cold tolerant. It matures in 65 days.
Cheddar is a bright orange hybrid cauliflower that matures in 58 days. It is best for a fall harvest but can also be grown in spring. It does not have great heat tolerance.
Clementine Hybrid is an orange cauliflower with medium-sized heads. It matures in 67 days. It tolerates both cold and heat well.
Depurple Hybrid has a lavender-blue head. It matures in 80 to 100 days with 5-inch heads.
Flame Star is a heat-tolerant orange hybrid cauliflower with 7-inch heads. It matures in 55 days.
Graffiti is a dark purple hybrid cauliflower that is best for fall harvest. It matures in 80 days.
Lavender is a bright purple hybrid cauliflower that is best grown as a fall-harvested crop, though it can grow in spring as well. It matures in 70 days.
Snowball Self-Blanching is a white heirloom cauliflower with approximately 7-inch heads. Its leaves wrap around the head in colder weather. It matures in approximately 70 days.
Snow Crown is a white hybrid cauliflower known for unusual vigor. It matures in 50 days and tolerates frost down to 25°.
Romanesco is a cross between cauliflower and broccoli. Two reliable varieties are Puntoverde and Veronica.
Cauliflower needs consistent moisture to succeed. One to two inches of water per week — including rainfall — is best. Consider installing a drip irrigation system to keep the soil moist but not drench.
To retain moisture between rain and supplemental watering, apply 2–3 inches of organic mulch around the plants, such as shredded leaves or straw. The mulch will also suppress weeds and keep the soil cool.
Cauliflower is a heavy feeder for its entire growing cycle, so regularly apply a nitrogen-rich organic liquid fertilizer, such as fish emulsion. Organic fertilizers are best because they won’t cause nitrogen burn as chemical fertilizers can.
Never exceed the manufacturer’s instructions when applying fertilizer. You can use less than the manufacturer recommends, but never more. Overfertlized cauliflower can grow hollow stems and it will be more vulnerable to pests.
Cauliflower that is underwatered or grown in low-fertility soil may have a purple tinge on the underside of the head. It is still safe to eat, but the flavor may be affected.
Cauliflower Pests & Diseases
Because cauliflower is a cole crop, it is affected by the same pests as cabbage, such as cabbage loopers and cabbage worms. You may see small white cabbage butterflies in your garden in mid-spring and early fall. When you see them, you know it’s time to install floating row cover, if you haven’t already. As you find cabbage worms, cabbage loopers and other caterpillars, you can handpick them or apply Bacillus thuringiensis, a biological control also known as Bt.
Aphids are sucking insects that spread plant diseases. As they feed on leaves they excrete honeydew, which attracts ants and other insects. They are easily controlled by knocking them off plants with a sharp stream of water. You can also apply insecticidal soap.
The flea beetle is a small black or bronze jumping leaf beetle that is just an eighth of an inch long. Cauliflower should be able to shrug off the damage. You can draw them away by planting a trap crop of radishes, which flea beetles prefer over brassicas.
Cabbage root maggots are fly larvae. Affected plants will wilt and have stunted growth. Use floating row cover before the flies have the opportunity to lay their eggs.
Diseases affecting broccoli include clubroot, black leg, ring spot, Botrytis stem blight and downy mildew. To lessen the occurrence of cauliflower diseases, refrain from overhead watering. Wet foliage provides an ideal environment for many of these pathogens, so watering around the base of the plants is the preferred method.
The best control method for cauliflower diseases is to remove the affected plants to reduce the spread. Pathogens can persist in soil for several years, so practice crop rotation — don’t plant any brassicas in the same spot for the next three years, at least.
As cauliflower matures, you’ll want to keep the sun off the developing heads so they stay white (or whatever color that variety is supposed to be). Some varieties naturally wrap their leaves over the head, but others will need your intervention. To protect the head, use a clothespin, rubber band or string to hold the leaves around it. Covering the head in this way is a technique known as “blanching.”
Harvest cauliflower when the heads are still compact. The average target size for harvesting is between 6 and 8 inches, though it’s far better to harvest too soon rather than too late. To harvest, cut the plant at the base of the neck.
Cauliflower can be stored whole in the refrigerator in an unsealed bag for up to two weeks. It can also be chopped up, blanched and frozen.
What are your secrets to grow cauliflower successfully? Let us know in the comments below.
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Links & Resources
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joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
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