Question: Do you need to cover cauliflower? How do I keep cauliflower heads white? -Sam R.
Answer: Blanching, the process of covering cauliflower heads with their own leaves, is essential to keeping cauliflower heads white, tender, and mild-tasting. Improper blanching leads to heads turning greenish-brown and turning coarse and bitter. Not to be confused with the blanching that requires boiling and cooling certain vegetables before freezing, blanching your cauliflower heads needs to be performed about three to four weeks after planting, when the heads are about the size of a ping pong ball.
There are some varieties of cauliflower that self-blanch, using their outer leaves, which naturally curl up around the head to protect it from direct sunlight exposure while it matures. Other varieties of cauliflower will need a helping hand to protect the heads from getting too much sun. Around three to four weeks after planting, start checking your plants daily.
Once the heads of your cauliflower plants reach ping-pong ball size, if the outer leaves haven’t started curling up around the heads on their own, gently wrap the outer leaves around the heads manually, gathering them together at the top of the plant and tie them together with a piece of string or a clothespin. You can also use a rubber band to hold them in place, but string or clothespins will put less stress on the leaves.
Be sure to tie them loosely as the head will need plenty of room to expand. Do not begin blanching if your plants are wet, as that can lead to fungal and rot issues. As each plant grows at its own pace, not all of your plants will be ready to tie up on the same day, so keep checking daily until all of your cauliflower plants are covered nicely.