Food Gardening Network

Growing Good Food at Home

Dealing with Cauliflower Diseases

Black mold on a cauliflower head

Black mold on a cauliflower head

Like most crops, cauliflower is susceptible to certain diseases, which are in turn promoted by pest damage. Here are some of the diseases you should look out for:


This is a fungus that causes erosion of the leaves, along with blackened stems and rotting roots. It impacts plants as young as the seedling state. Prevent blackleg by using quality, disease-free seed, good drainage and air circulation, and regular crop rotation. You can also try a fungicide to kill the disease.


This is another fungal disease that likes acidic, moist soil. Roots attacked by clubroot fill with mold spores that deform the roots into useless appendages. If your plants are failing, dig down to see if the roots are healthy or if they’re smelly and deformed. If they’re damaged, discard the plant in the trash, and don’t plant brassicas in the same spot next year.

You can try a fungicide too, before deciding your plant is a total loss. Well-drained, neutral soil is a good preventive.

Damping off

Brassica seedlings may be attacked by various soil-borne fungi that feed on roots and stems. The attack appears to be sudden, with everything fine one day and seedlings dead the next.

Avoid damping off by planting in clean containers with good drainage and providing good air circulation between plants. Some seeds are even pre-treated with fungicide. Other than that, there’s not much hope for plants that are victims.

Downy mildew

This is a fungus that can destroy crops. Watch for yellow patches that turn brown and fluffy white on the underside of leaves. Infected seedlings may not survive damage to their first leaves, and the disease progresses to stem and flower heads.

If you spot signs of trouble, try an organic fungicide that’s safe for food plants.

Finally, best practices for preventing disease include crop rotation, controlling for pests that spread disease, and constant vigilance. Discard diseased plants in the trash, not the compost heap.

How do you prevent diseases on your plants? Please share your techniques with us in the comments.


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