How to Grow Cauliflower: Your Complete Guide

Written by Cammi Morgan
Published: March 27, 2023
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A cool-loving plant widely used in various dishes worldwide for its unique texture and nutty flavor, cauliflower is an excellent choice for gardeners seeking to grow a nutritious and delicious food source. Available in white, orange, purple, and green varieties, you can grow a colorful array of cauliflower cultivars that are packed with antioxidants and essential vitamins.

In this guide, we’ll cover the botanical classification of cauliflower, its native range, its characteristics, and how to grow it from seed and through transplanting.

Alright, let’s jump in!

Cauliflower: Botanical Classification, Native Range, and Characteristics

Wonder how to grow cauliflower? Our guide tells you everything to know for a good crop.

©iStock.com/Tim UR

A domesticated descendant of wild cabbage (Brassica oleracea), cauliflower is a member of the Brassicaceae family of flowering plants. As a domesticated variety of B. oleracea, cauliflower’s botanical name is Brassica oleracea var. botrytis.

Wild cabbage is native to the Eastern Mediterranean and Southern and Western Europe, where farmers began domesticating this plant over 2,000 years ago. One of the earliest literary references to domesticated crops of B. oleracea dates back to ancient Greek texts from the 6th century BC. Cauliflower is likely a more recent domesticated variety of wild cabbage cultivated by farmers in or near Cyprus around the end of the 15th century.

Through natural mutation and selective breeding, cauliflower is now available in four colors: white, orange, purple, and green. The first record of an orange cauliflower is traced back to 1970 when a Canadian farmer discovered an orange cauliflower in his field that was smaller and less flavorful than his crop of white cauliflowers. Researchers who studied the orange cauliflower confirmed it contained a higher amount of beta-carotene, brought on by a natural mutation. After this discovery, horticulturists then purposely bred orange cauliflowers to produce their vibrant hues while remaining flavorful.

Plant breeders have also since cultivated purple cauliflowers by increasing the production of anthocyanins in the plant, which is responsible for red-purple pigmentation. The fourth color of the cauliflower head you may notice is green, but this is actually produced through breeding broccoli with cauliflower, resulting in a hybrid of the two B. oleracea varieties.

How to Grow Cauliflower

Gardener holds a head of caulifower against the background of a green garden

Cauliflower gets its white leaves because it’s protected from the sun.

©iStock.com/Alexlukin

To grow this brassica, you’ll need to know its suitable climate zones, ideal soil and sunlight conditions, watering and fertilizer requirements, and how to direct sow the seeds and transplant them. Below, we’ll discuss all of this in-depth to help you produce a successful, abundant cauliflower crop.

USDA Growing Zones Suitable for Cauliflower

Depending on the variety and heat tolerance of the cultivar, you can grow cauliflower in USDA growing zones 2-11. Cauliflower, like many brassicas, does best in cool growing conditions in which daytime temperatures don’t consistently reach over 75 degrees Fahrenheit. However, you can readily grow them in warmer regions between zones 8-11 if you choose a heat-tolerant cultivar with a short growing period, such as ‘Mardi’ or ‘Flame Star’.

How to Grow Cauliflower: Ideal Soil Conditions

Like other wild cabbage varieties, Cauliflower prefers to grow in well-draining, moist, loamy, fertile soil with a slightly acidic-to-neutral pH (6.0-7.0). As a fairly hardy plant, you can grow cauliflower in less-than-ideal soil types, but you will likely need to amend these soils with well-aged compost to support healthy growth.

Suppose you choose to till your soil to temporarily resolve compaction issues for cauliflower plants. In that case, it’s best to till to a depth of 6-10 inches and incorporate 4 inches of well-aged compost, as these plants require high-nutrient content in their soil. While loosening the soil, you should remove medium-to-large stones and sticks, as brassica roots tend to have difficulty working their way around obstacles in the soil.

Ideal Sunlight Conditions

Provide at least 6 hours of full sun for these plants to support the production of dense, large cauliflower heads. Lack of sunlight can result in leggy plants with thin stalks and loose, smaller heads.

How to Grow Cauliflower: Watering Requirements

Cauliflower requires ample water to produce delicious-tasting heads.

©iStock.com/Baloncici

Consistent watering is crucial to healthy cauliflower development and to producing heads that don’t taste bitter. Depending on the variety and your growing climate, you’ll need to provide 1-2 inches of water per week per square foot of the garden. This equals about .5-1 gallon of water per square foot of garden bed per week. When you’re providing adequate water for your cauliflower, the soil should be consistently moist, but never soggy or puddly.

Fertilizer Requirements

Generally, cauliflowers are heavy feeders throughout their entire growing phase and need to grow in highly fertile soils to thrive. Your cauliflower will thrive independently if you have a healthy topsoil teeming with a strong microbial soil population. However, most of us aren’t growing in ideal soil with a healthy, thriving top layer. So, we must provide nutrients directly to the plant through well-aged compost or fertilizer mixes.

You can mix high-nitrogen compost into the soil prior to planting, such as well-rotted manure-heavy compost. Then, feed every 2-4 weeks with an organic fertilizer such as fish emulsion or with a high-nitrogen NPK (nitrogen-phosphorus-potassium) mix.

How to Grow Cauliflower: Direct Sow Seeds into Your Garden

Unless you live in climates zones 2-4, or have intentionally chosen a fast-growing, heat-tolerant cultivar, it’s best to direct-sow cauliflower seeds in the early fall after daytime temperatures have dropped below 75 degrees. One of the fastest cultivars that are heat-tolerant is ‘White Corona’, and it is generally ready for harvest in 30-35 days. ‘Flame Star’ is an orange cultivar that is ready for harvest in about 60 days and produces large heads with a nutty, buttery taste.

The germination temperature range for cauliflower is 45-85 degrees Fahrenheit, but the ideal temperature for fast germination is about 70 degrees. At that temperature, you can expect germination to occur in about 5 days. So, ideally, direct sow your seeds when temperatures have reached about 70 degrees, but remember that temperatures shouldn’t go much higher than this during the plant’s growing season.

Sow your seeds in the soil between 1/4 and 1/2 inches deep, spacing a seed every 6 inches. Space rows about 30 inches apart. Once the seedlings are 4-6 inches tall, you can thin them so there is one plant every 18 inches. Depending on your cultivar and climate, expect plants to be ready for harvest in 35-100 days.

If you want to keep your white cauliflowers stark white, you’ll need to “blanch” them by tying the large outer leaves together to cover the heads, so they don’t turn yellow-pale brown in the sun. Blanch when heads are about 2-3 inches in diameter. You can only harvest the plant once, so you can extend your harvest season by staggering your planting times or growing varieties that mature at different times.

How to Transplant your Cauliflower Seedlings into Your Garden

If you’ve started your seeds indoors or bought seedlings from a nursery, you’ll need to transplant them into your garden once the plants have developed 4-5 mature leaves.

Before the plant matures, it can withstand temperatures down to about 31 degrees Fahrenheit. So, you can usually transplant your seedlings into the garden about 2 weeks before the last expected frost, as long as your area doesn’t tend to drop below this temperature at night. Ideally, when transplanting your seedlings, daytime temperatures should be around 45-50 degrees Fahrenheit. You’ll want to transplant your seedlings outside about 6-10 weeks before the first expected frost date for a fall crop.

Pick an overcast, non-windy day to transplant to reduce the risk of transplant shock. Space the holes about 18 inches apart and plant your seedlings into moist, workable soil about an inch deeper than the depth of their current containers.

Acclimating Seedlings to the Outdoors

Make sure to acclimate the seedlings to outdoor conditions before transplanting if the seedlings have yet to live outside. Harden them off to outdoor temperature and full sun conditions over a period of a week by gradually increasing their time outside in the full sun. Start by placing them in a partially-shaded area for a couple of hours per day when daytime temps are above 50 degrees Fahrenheit, and gradually decrease their time in the shade and increase their time in the sun until they are sitting in the full sun for at least 6 hours.

At the same time, gradually increase the time they spend in cooler conditions at night by gradually acclimating them to nighttime temperatures until they spend all night outside. You can add a few layers of leaf insulation to the containers at night to help protect them from the cold. Once they are acclimated to full sun and nighttime temps that don’t fall below 31 degrees, they’re ready for transplanting. After transplanting, you can mulch around the plants to increase moisture and nutrient retention and further protect young seedlings from cold temperatures.

The photo featured at the top of this post is © iStock.com/Baloncici


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About the Author

Cammi Morgan is a writer at A-Z Animals where her primary focus is on mycology, marine animals, forest and river ecology, and dogs. Cammi has been volunteering in animal rescue for over 10 years, and has been studying mycology and field-researching mushrooms for the past 3 years. A resident of Southeast Appalachia, Cammi loves her off-grid life where she shares 20 acres with her landmates, foster dogs, and all the plants, fungi, and critters of the forest.

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