Pests & diseases › Powdery Mildew
Powdery Mildew
White powdery fungal coating on leaves. Worst on squash, cucumbers, melons, peas late summer.
Symptoms
- White powdery patches on upper leaf surfaces
- Coating spreading to cover whole leaf and stems
- Leaves yellowing and crisping
- Reduced yields, smaller fruit
Lifecycle
Thrives in warm dry days and humid nights.
What to do
- Remove worst leaves — bag, don't compost
- Milk spray (1 part milk to 9 parts water) weekly — proven suppressant
- Baking soda spray (1 tsp per quart water + drop of dish soap)
- Neem oil
- Improve airflow — thin lower leaves
If it's bad
- Sulfur-based fungicides — organic-approved
- Potassium bicarbonate products (Kaligreen)
Stop it coming back
- Water at base of plant, never on leaves
- Deep mulch keeps roots cool and moist
- Wide spacing for airflow
- Resistant squash varieties: Success PM, Trombetta, Dunja
Crops it goes for
Plan the plot, track every sowing, cook the harvest
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.