How to Grow Cauliflower: Planting, Spacing, Care & Harvest
Quick answer
NDSU: start indoors about 10 weeks before last frost and transplant about 3 weeks before. UMD: set out 5- to 7-week-old transplants 3 to 4 weeks before the frost-free date; Mid-Atlantic gardens often do better with a fall crop. Blanch white types when the head is about 2 inches across. Days to maturity: Clemson 60 to 70; UMD 50 to 80 from transplant.
Cauliflower at a glance
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.
Organic pests and diseases: see also organic pest control. Use any product as the label directs.
Cole crop: same species complex as broccoli and cabbage — rotate away from other brassicas. See also broccoli, cabbage, and cabbage-family companions.
Planting timing
UMD: semi-hardy (light frost OK, not heavy freeze). “Set out 5- to 7-week-old transplants 3 to 4 weeks before the frost-free date.” Seed flats for fall transplant or direct seed. Mid-Atlantic: better success with fall; sow seed early July; set transplants late July to early August. (UMD Extension) NDSU time chart: cauliflower sow 10 weeks before last frost; transplant 3 weeks before last frost. (NDSU H1139) The planner uses start indoors last frost −10 and transplant −4 to −3 to cover NDSU (−3) and UMD (−4 to −3). UMN: spring — start indoors early to mid-April (MN calendar) with short-cycle heat-tolerant types; fall — start indoors or direct seed early to late July. Dense curds in cool weather 50°F to 70°F. (UMN Extension) Buttoning: UMD failure of the head to enlarge past about an inch — stress from overgrown transplants or hot/cold swings; planting too early in spring risks buttons.
Depth and spacing
Seed depth: UMN press seeds one-fourth to one-half inch deep (indoors or direct). Direct seed July: drop three seeds every 18 inches, then thin to one. Spacing: UMD 18"–24" in-row × 24"–36" between rows. UMN transplants 18 inches apart. Clemson chart: 36 × 18 inches, depth ½ inch, days 60–70. (Clemson HGIC) In-row and between-row figures differ by source, so we show each.
Sun, soil, water and blanching
Sun: UMD full sun ≥6 hours (prefers 8–10). Soil: UMN well-drained yet moisture-retentive, fertile, pH 6 to 7; compost or well-rotted manure; no fresh manure; no “Weed and Feed.” Rotate: do not plant where cabbage-family crops grew in the past four years (UMN). Water: UMN must not drought-stress — about one inch of rain/irrigation per week (more on sand); uneven moisture → off flavors / poor texture. Mulch three to four inches. Blanching (white types): UMD when head ~2 inches across, tie outer leaves over the curd; blanch 4 to 8 days (longer in fall); tie loosely in warm weather. UMN gather outer leaves when the head becomes visible. Do not blanch orange/green/purple/Romanesco — they need sun for color (UMN). Self-blanching types exist (UMD/UMN) — no names on this page.
Care
Fertilizer: UMD high nutrient need; starter at transplant; side-dress three weeks later and as needed. UMN side-dress when plants about four inches tall. Row cover: UMN protects from wind and insects early; use cold-protection fabric in spring, lightweight in summer; anchor well.
Harvest and storage
Days to maturity: UMD 50–80 from transplanting. Clemson 60–70. UMD: cut before flower sections separate; curd compact, firm, white, fairly smooth; leave a ruff of leaves; grainy when overmature. UMN: harvest usable size before flower buds open; spring plantings loosen faster; fall holds quality better in cold. Storage: UMD very cold, moist (95% RH), 2 to 4 weeks. UMN about one week in the refrigerator; even in cold moist conditions not more than three weeks. Freeze or pickle surplus (UMN).
Pests and diseases (organic)
Imported cabbageworm, cabbage looper, diamondback moth: UMN cole-crops guide: handpick into soapy water; floating row covers from seeding/transplant until harvest; destroy crop residue; remove mustard-family weeds. Low-risk options: Bt (must be eaten by caterpillars), spinosad, neem (stops feeding), pyrethrins (contact) — follow the label; treat while larvae are small. (UMN cole crops caterpillars)
Flea beetles, cabbage maggot, harlequin bug: UMN cauliflower page: flea beetles chew small holes (seedlings most vulnerable); cabbage maggots on roots; Swede midge can prevent crown. UMD problem list: cabbage looper, flea beetles, harlequin bug, imported cabbageworm. Row cover from planting is the main organic physical control (UMN).
Diseases: UMN Alternaria (leaf/crown spots), black rot (yellow triangles, crown rot), clubroot (swollen roots, stunt). Cultural: rotation, drainage, reduce leaf wetness. Disorders: boron deficiency browns florets; stress → small heads; hot weather (86°F day / over 77°F night) can prevent crown (UMN).
Related: how to grow broccoli · how to grow cabbage · cabbage-family companions · organic cabbage · organic pest control · ZIP planner
Frequently asked questions
When do I transplant cauliflower?
UMD: 3–4 weeks before frost-free date with 5- to 7-week-old plants. NDSU chart: 3 weeks before last frost. Prefer fall crop in Mid-Atlantic (UMD).
Why did my head stay tiny (button)?
UMD: stress — overgrown transplants, planting too early, or temperature swings during head formation.
How do I keep white cauliflower white?
Tie leaves over the curd when it is about 2 inches across (UMD); skip tying on colored/Romanesco types (UMN).
How do I stop cabbageworms organically?
Row covers, handpicking, Bt or spinosad per label (UMN cole crops).
More grow guides: Asparagus · Peas · Rhubarb · Leeks · Parsley · Swiss chard · Radishes · Eggplant · Arugula · Cilantro · All grow guides
Sources
- University of Maryland Extension: UMD Extension
- North Dakota State University Extension: NDSU H1139
- University of Minnesota Extension: UMN Extension; UMN cole crops caterpillars
- Clemson Cooperative Extension: Clemson HGIC