Harvesting Cauliflower Seeds: Where Do Cauliflower Seeds Come From

These cauliflower seeds are ready to plant.
Image by ErikaMitchell

By Amy Grant

I love cauliflower and usually grow some in the garden. I generally buy bedding plants although cauliflower can be started from seed. That fact gave me a thought. 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:


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 and mix in compost to a 6 inch 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 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 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 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.

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