Clubroot
Swollen, club-shaped roots on cabbage-family plants, which wilt on warm days and stay stunted.
What you'll see
- Plants are stunted, with yellow or purplish leaves that wilt in hot weather and recover when it cools.
- Dig one up: the roots are swollen, knobbly and distorted, with few fine roots.
- Affects cabbage, broccoli, cauliflower, Brussels sprouts, turnips and relatives such as alyssum.
Why it happens
A soil-dwelling organism related to slime molds infects the roots. Its spores survive in soil for many years and spread on soil, tools, boots and transplants, and acid, wet soil favors it.
How to fix it
- There is no cure: dig up infected plants with all their roots and put them in the trash.
- Raise acid soil to about pH 7.2 with garden lime, guided by a soil test and the label.
- Improve drainage, for example with raised beds.
- Clean soil off tools, boots and wheelbarrows after working in the bed.
Keep it from coming back
- Buy cabbage-family plants from a clean source, or raise your own.
- Grow resistant varieties, and start transplants in larger pots so roots establish before planting out.
- Don't grow cabbage-family crops in infected beds for many years, and pull mustard-family weeds.
Sources
General guidance, not a diagnosis. For valuable, edible or outdoor crops, check with a local extension service or plant expert. Use any product exactly as its label says, and keep children and pets away while it dries.