Dark Spots on Cauliflower Leaves
Set your conditions — the recommendation updates instantly.
GardenSays
Best match: Black rot. Manageable if you act.
- Best match
- Black rot
- Severity
- Act soon
- Causes checked
- 1
Based on yellow spots at leaf edges or a rotting crown on the lower leaves with moist soil, the closest match is black rot. Confirm it against the actual plant: Yellow, V-shaped lesions at the leaf margin; on cauliflower this can progress to rot in the curd (crown) itself.
- This is a symptom-pattern match from your written description, not a lab diagnosis. If the plant is collapsing over days (not weeks), treat it as the worst plausible cause until ruled out.
Do this this week
- 1.Confirm it first: Yellow, V-shaped lesions at the leaf margin; on cauliflower this can progress to rot in the curd (crown) itself.
- 2.No cure. Remove affected leaves/plants promptly to protect the developing head; avoid overhead watering; rotate out of that bed for 3-4 years.
- 3.Collapsing fast (days, not weeks)? Photograph it and check with your county extension before treating
Calculated result · 2 verified sources · Checked 2026-07-17 · How we decide
Why
What to do: No cure. Remove affected leaves/plants promptly to protect the developing head; avoid overhead watering; rotate out of that bed for 3-4 years.
- A symptom tree ranks causes by how well your conditions match each cause's known pattern — the distinguishing signs are how you confirm it on the actual plant, not a lab result.
- Most leaf problems trace to water, weather, or common leaf-spot fungi; true plant-killers are rarer but worth ruling out first.
When this doesn't apply
- If the plant is collapsing fast (days, not weeks), treat it as the most severe possibility on the list until proven otherwise.
- Multiple symptoms at once usually means the top cause here plus plain stress — fix watering first, then re-check.
How this was calculated
- 1. SymptomSource guidance
Cauliflower: yellow spots at leaf edges or a rotting crown — 1 known cause evaluated (extension-sourced)
- 2. Your conditionsCalculated result
Location on plant: lower; soil: moist. Causes whose known pattern matches these conditions rank higher — this narrows the list, it doesn't identify anything.
- 3. 1. Black rotmatch score 1Calculated result
Distinguishing signs: Yellow, V-shaped lesions at the leaf margin; on cauliflower this can progress to rot in the curd (crown) itself.
Data sources
- University of Minnesota Extension — Clubroot — Plants are stunted or wilt with only slight drought stress; leaves may yellow; older plants fail to produce a harvestable head; roots are swollen and distorted into large clubs, firm and light-colored early in the season. (checked 2026-07-17)
- University of Minnesota Extension — Black rot of Brassica crops — Black rot causes yellow, V-shaped/triangular lesions at the leaf margin and can rot cauliflower crowns; most damaging in broccoli, cabbage, cauliflower and kale. Bacteria enter through leaf-margin pores (hydathodes) where morning dew collects, or through wounds. (checked 2026-07-17)
What changes this answer
Where on the plant?
Soil right now
Every change updates the answer, the math, the weekly steps and the share link instantly.
Your next decisions
More plant problems tools: see all →