Time Is Ripe for Planting a Cabbage-Family Garden

Cool Season Vegetables: Grow Broccoli, Cauliflower, and Brussels Sprouts

Now that cooler weather should be on its way, you may think that the vegetable gardening season is over. Think again. There are plenty of “brassicas”—broccoli, cauliflower, and Brussels sprouts—that thrive during cool, damp days and even taste better when touched by a little frost.

Why Grow Brassicas?

“Many people don’t realize that you can grow these plants,” says Audrey Van Dellen of Roger’s Gardens in Corona del Mar. “People think they’re too complicated to grow, but that isn’t true. They do very well and can produce a great deal. One Brussels sprout plant can bear 100 or more sprouts.”

When and How to Plant

  • Plant now—nurseries are stocking seedlings ready for harvest in 60–80 days.
  • Seeds take about 30 days longer to mature than seedlings.
  • Check nursery plants to ensure they are not root-bound. A few visible roots are fine, but avoid plants with roots growing out of the bottom of the container.

Soil Preparation

  • No need to adjust pH—brassicas prefer 6.0 to 7.5 pH.
  • If soil is hard or clay-like, add compost and planting mix.
  • Use 3–4 cubic feet of planting mix per 100 square feet.
  • Boost nitrogen with organic matter like:
    • Blood meal
    • Aged manure (guinea pig, steer, horse, rabbit, or chicken)
  • High-nitrogen granular or liquid fertilizers also work well.

Tips for Growing Broccoli

  • More heat-tolerant and less likely to bolt than other brassicas.
  • Grows to about 3 feet tall and wide.
  • Harvest main head when it reaches 6 inches in diameter.
  • Side shoots will continue producing for 8–10 weeks.
  • Fertilize when:
    • 6–8 inches tall
    • 12–15 inches tall
    • 2.5–3 feet tall

    Use a 5-10-10 fertilizer.

Tips for Growing Cauliflower

  • More sensitive than broccoli—wait until hot weather passes.
  • Grows to about 2.5 feet tall and wide.
  • Requires fertilizing every 2–3 weeks with 10-10-10 fertilizer.
  • Be cautious when fertilizing—roots are shallow and delicate.
  • Blanching is required for a white head:
    • When the head is quarter-sized, pull outer leaves over it.
    • Secure with a rubber band or twist tie to block sunlight.
    • Harvest in 2–3 weeks when the head reaches 4–6 inches.

Tips for Growing Brussels Sprouts

  • Most challenging of the three—needs cool weather to thrive.
  • Plants grow 2–4 feet tall; sprouts develop from bottom up.
  • Pick when sprouts are about 1 inch in diameter.
  • Harvest from bottom to top for up to 8 weeks.
  • Fertilize at:
    • 6–8 inches tall
    • 12–14 inches tall
    • When sprouts begin forming

    Use a 5-10-10 fertilizer.

Pest Control

Common pests that affect all three plants include:

  • Cutworms: Protect seedlings by placing a bottomless paper cup around the stem and into the soil.
  • Cabbage loopers: From white butterflies; use BT-based products like Dipel or Attack.
  • Aphids: Especially problematic for Brussels sprouts—control with a strong spray of water.

To deter cabbage moths naturally, interplant brassicas with:

  • Onions
  • Garlic
  • Chives
  • Leeks
  • Aromatic herbs like dill, fennel, and anise

Care and Growing Conditions

  • Keep soil consistently moist; mulch with straw to retain moisture and reduce weeds.
  • These plants require 4–6 hours of sun at least five days per week.
  • If space is limited, use large containers like whiskey barrels. Broccoli performs best in containers.

Julie Bawden-Davis

Julie Bawden-Davis is a bestselling journalist, novelist, blogger, and YouTuber. A prolific author, Julie writes in several genres. She enjoys creating page-turning suspense served up with a dose of romance, garden books that turn any brown thumb green, and spiritual books meant to enlighten and inspire. Widely published, Julie has written 45 books and more than 4,000 articles for a wide variety of national and international publications. She lives in Southern California, where she enjoys sunny, blue skies most days and year-round gardening. Julie gains inspiration from being surrounded by plants when she writes.