Harvesting Cauliflower Seeds: Where Do Cauliflower Seeds Come From

I love cauliflower and usually grow some in the garden. I generally buy bedding plants although cauliflower can be started from seed. Where do cauliflower seeds come from? I’ve never seen them on my plants. Let’s learn more.

Growing Cauliflower Seeds

Cauliflower is a cool season biennial in the Bassicaceae family. Amongst its species name of Brassica oleracea, cauliflower shares ties with:

  • Brussels sprouts
  • Broccoli
  • Cabbage
  • Collards
  • Kale
  • Kohlrabi

Generally, cauliflower is white, although there are some colorful purple varieties out there and even a green spiky variety called Veronica Romanesco.

Cauliflower needs well-draining, fertile soil that is rich in organic matter. While it prefers a soil pH of 6.0-7.5, it will tolerate slightly alkaline soil. Prepare the bed by tilling the soil down to 12-15 inches (30-38 cm.) and mix in compost to a 6 inch (15 cm.) depth. Choose a site with at least 6 hours of full sun.

Plant seeds three weeks before the last frost for spring or seven weeks prior to the first frost for fall crops, or start seeds indoors 4-6 weeks before the average last frost free date. If you start the cauliflower indoors to be transplanted, keep in mind that it doesn’t like to have its roots messed with. So, it is best to start the seeds in peat or paper pots.

Plant the seeds ½ to ¼ inches (0.5-1.25 cm.) deep and keep moist and in a warm area of between 65-70 degrees F. (18-21 C.). When the growing cauliflower seeds are ready to transplant, be sure to harden them off before setting them into the garden.

Space plants 18-24 inches (45-60 cm.) apart to give them plenty of room for their large leaves. Keep the plants moist or the heads become bitter. Also, feed the plants with an organic fertilizer every 2-4 weeks.

Where Do Cauliflower Seeds Come From?

Okay, now we know how to grow cauliflower from seed, but what about saving cauliflower seeds? As with other Brassica members, cauliflower only sends up stalks in their second year. In the first year, the plant produces a head and, if left unpicked, in the second year seed pods emerge in summer. In a warm climate, getting them to bolt is easy but in a cold climate, harvesting cauliflower seeds is a little more labor intensive.

The first thing to know if saving cauliflower seeds is that the plants are insect pollinated and, as such, they will cross with all other members of Brassica. You need an isolation area of ½ mile (805 m.) for pure seed. Buildings, tree lines and woods cut down on this isolation area.

If you are bound and determined to save seed, you probably want to set aside at least 6 of the healthiest plants. Don’t harvest the heads. They need to stay on into the second year. If you live in warm climate, the cauliflower can stay in its bed for the two years it takes to produce seeds. But, if you live in an area that has extended freezing, the plants need to be dug up in the fall. Store them over winter and then replant them in the spring.

If your temps typically only drop below freezing for a few weeks, but not below 28 degrees F. (-2 C.), you can plant cauliflower in the fall and harvest seed the next summer.

Harvesting Cauliflower Seeds

To harvest the seeds, gather the seed stalks when the seed pods are fully mature and dry on the plant. Use a screen to winnow the chaff from the seed. You can store seeds in a cool, dry area for up to 5 years.

Planting Cauliflower

Site. Cauliflower grows best in rich, well-drained, moisture-retentive soil with a pH within the 6.5 to 8.0 range. Plant cauliflower in full sun. Broccoflower prefers partial shade. Add aged compost to planting beds before planting.

How to Grow Cauliflower: Cauliflower is a cool-weather crop that requires 55 to 100 days of cool, even temperatures to reach harvest

Cauliflower Planting Time. Cauliflower requires 55 to 100 days of cool, even temperatures to reach harvest. Start cauliflower seed indoors 6 to 10 weeks before the last frost in spring. Cauliflower germinates at 45°F (7°C). (Cauliflower is usually grown from transplants.) Transplants can go into the garden 2 to 6 weeks before the last frost, usually 6 weeks after sowing when plants have 4 to 5 true leaves. Direct seed cauliflower into the garden where the soil temperature is between 65°F and 75°F (18-24°C) and the weather will remain cool. Crops for a fall harvest can be direct-seeded 8 to 12 weeks before the first expected frost in fall. Cauliflower does not like extremes of temperature, hot or cold it does not tolerate dry conditions. Plant cauliflower in autumn for a winter harvest where winters are mild and frost-free. Extreme temperatures will cause cauliflower to bolt and go to seed.

Cauliflower Planting and Spacing. Sow cauliflower seeds ½ inch deep and 2 to 3 inch (2.5-7.6cm) apart. Thin plants to 15 to 24 inches (38-61cm) apart space rows 24 to 30 inches (61-76cm) apart. Set leggy or cooked-stemmed transplants deeply, up to their first leaves, so that they will not grow top-heavy. For succession crops, plant a couple of heads at a time or plant early and midseason varieties at the same time.

Companion plants. Beets, celery, herbs, onions, potatoes. Avoid pole beans, strawberries, tomatoes.

Container Growing Cauliflower. Grow cauliflower in a container at least 8-inches (20cm) deep. In large containers, plant cauliflower on 18-inch (45cm) centers.

How To Grow Cauliflower – Tips and Tricks

Cauliflower is a member of the Brassica family (broccoli, kale), and like it’s relatives, prefers cooler weather. Cauliflower will develop tiny button-sized heads if it becomes stressed from mid-summer heat.

That means its best to plant in early spring for a mid-summer crop. In many areas, it can also be planted in late summer for a second fall crop.

For spring planting, it’s best to start seedlings indoors 4 to 6 weeks before the last frost.

Once the threat of frost has passed, set plants in rich, fertile soil. Cauliflower requires plenty of Nitrogen and Potassium, so amending the soil with compost or aged manure will ensure plenty of nutrients on hand for good growth.

When planting, space plants 18 to 24″ inches apart, with at least 24″ between rows.

Cabbage worms can wreak havoc on tender Cauliflower plants

For a late season crop, sow seeds directly into the garden 10 to 12 weeks before your anticipated first frost of fall.

A mid-summer planting matures faster due to the warmer soil, so that leaves plenty of time for growth.

There are many great varieties to choose from including purple and yellow cauliflower!

The key to success is to choose a variety that matures fast enough in your climate zone before heat (summer) or frost (fall) sets in. See Seed Links : Multi-Color Mix, Purple, Yellow, White – Snowball (Early White)

As the cauliflower head develops, be sure to cover the head with it’s leaves for it’s last few weeks before harvest.

This will naturally blanch the head of the cauliflower to ensure that it will be white and tender for eating.

Cauliflower does well when planted with or near beans, broccoli, brussel sprouts, cucumbers, and corn.

Protecting Your Crop

Cauliflower can be affected by a handful of pests, most notably cabbage worms. Inspect the leaves and heads daily, and hand-pick any worms to keep damage to a minimum.

If you are prone to heavy infestations, row covers are an easy and inexpensive option to protect crops from damage. Product Link : Row Covers

Heads can be harvested when they reach 6 to 8 inches in diameter. For more vegetable garden tips – check out our Vegetable Garden tab on the blog.

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Planting cauliflower seedlings outdoors

Whether you’re planting seedlings you raised yourself or those purchased from a local nursery, transplant seedlings on a temperate day and when there is no extreme weather in the forecast for the coming week. Also, be sure to harden off indoor-raised seedlings before transplanting them outside. If you do opt to buy nursery seedlings, remember that bigger isn’t always better! Large seedlings may be overgrown and root bound in their small pots. Choose the most tender, fresh, and healthy-looking seedlings. Check them for pests or signs of disease before bringing them home.

  • Spring planting: In spring, plant cauliflower seedlings outdoors about 2 to 4 weeks prior to your zone’s last spring frost date. Be prepared to protect outdoor seedlings from freezing weather with frost row covers, cloches, halved plastic milk jugs, or other forms of frost protection!
  • Summer/fall planting: For a fall crop, transplant cauliflower seedlings outdoors 6 to 8 weeks before your first fall frost date. However, it is best to wait until daytime temperatures are regularly below 75°F. Remember, cauliflower plants prefer cool soil! Therefore, plan to provide some shade (e.g. using shade cloth) during high heat as needed.

A happy little cauliflower baby, being transplanted on a mild fall day.

Cauliflower seedlings available at our local nursery. These are both snowball cauliflower, but notice how much healthier the seedlings on the left look (the better choice). The ones on the right appear to be overgrown, leggy, stressed, and ready to bolt!

Cauliflower Varieties to Grow

Check the cultivar to be sure it is suited to the growing season: spring, summer, and autumn, or winter.

  • White: ‘Candid Charm’ (75 days) ‘Cashmere’ (52 days) ‘Dominant’ (68 days) ‘Inca White’ (70 days) ‘Incline’ (76 days) ‘Majestic’ (66 days) ‘Ravella’ (70 days) ‘Rushmore’ (51 days) ‘Self-Blanche’ (70 days) ‘Serrano’ (63 days) ‘Sierra Nevada’ (68 days) ‘Siria’ (65 days) ‘Snowball’ (59 days)’ Snow Crown’ (50-68 days) ‘Snow King’ (60 days)’ Pak’ (62-85 days) ‘Solide’ (67 days) ‘Starbrite’ (68 days) ‘Super Snowball’ (55 days) ‘White Rock’ (69-100 days) ‘White Sails’ (68 days) ‘Yukon’ (71 days).
  • Purple: ‘Burgundy Queen’ (70 days) ‘Sicilian Purple’ (85 days) ‘Purple Cape’ (200 days) ‘Violet Queen’ (55-65 days).
  • Green and Broccoflower: ‘Chartreuse’ (62 days).

Common name. Cauliflower

Botanical name. Brassica oleracea botrytis

Origin. Europe, Mediterranean


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