Covering cauliflower is essential for keeping heads white, mild-tasting |

Covering cauliflower is essential for keeping heads white, mild-tasting

Jessica Walliser
Blanching cauliflower heads — covering them with their own leaves — helps develop the white color.

Question: I’m growing cauliflower in my garden for the first time this year. I understand I have to blanch the heads in order to make them white. How do I do this?

Answer: Improper blanching sends many homegrown cauliflower heads to the compost heap instead of to the kitchen. Without blanching, cauliflower curds turn greenish brown and taste slightly bitter. Learning how and when to blanch cauliflower heads is an important step in growing this vegetable.

Blanching is a technique growers use on several different vegetables. It involves covering all or part of a plant to shield it from sunlight and prevent it from developing color pigments. In the case of cauliflower, the developing flower bud is protected from light to keep the color white and the flavor mild. Blanching also is used when growing white asparagus, celery, chicory and leeks.

Because cauliflower is a cool-season crop, it’s planted in very early spring, usually in late March here in Pennsylvania. In order to have beautiful, white cauliflower heads, the blanching process should begin the moment the flower bud reaches the size of a ping-pong ball. This can be as early as three to four weeks after planting. Check your plants daily, and when the flower bud reaches this size, start the blanching process. The heads grow fast, so if you miss this window, your chances of success greatly decrease.

To blanch the developing cauliflower bud, head to the garden on a dry day with one rubber band or clothespin for each cauliflower plant. Fold the large, outer leaves together over the developing curd. Loosely gather them at the top of the plant and fasten them together with the rubber band or clothespin. Don’t tie them too tightly as the head will need room to expand, and don’t start the blanching process if the plants are wet; this can lead to fungal and rot issues.

Not all of your plants will be ready to blanch on the same day. Go out to the garden daily and band plants based on their development stages.

After the blanching process begins, head growth occurs rapidly. Start peeking inside the folded leaves three to five days later, checking the head’s development. It takes anywhere from a few days to two weeks for them to reach maturity.

Please note, however, that this blanching process might not even be necessary. Many of the newer cauliflower varieties available are self-blanching. They have leaves that are bred to naturally fold together and curl over the developing curds. However, I find that even the self-blanching types sometimes need a little help. If large heads develop, the leaves might not be long enough to fully cover the entire head. Or, if your garden is in a windy area, the leaves don’t always stay in place, and light gets through. Even the leaves of self-blanching cauliflower varieties sometimes need to be secured for the best blanching.

If you find your cauliflower forms tiny heads (called buttonheads) instead of reaching full size, know that you aren’t alone. Cauliflower is temperamental. If the weather is too hot or too cold, or if the transplants sit in their tiny nursery packs for too long, they will not develop properly.

Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control” and “Good Bug, Bad Bug.” Her website is

Send your gardening or landscaping questions to [email protected] or The Good Earth, 503 Martindale St., Third Floor, Pittsburgh, PA 15212.

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