Bordeaux mixture (copper)

How it works

Copper ions destroy fungal spores as they land and try to germinate. It forms a protective film on bark and buds - it cannot cure an infection already inside the plant.

Recipe

Buy ready-formulated Bordeaux mixture and follow the label (typically 10-20 g per litre for dormant sprays). Mix in a plastic container, never metal, and use the same day.

How to apply

Peach and almond: spray at leaf-fall (Nov-Dec) and again as buds swell (Jan-Feb) - AFTER the leaves drop and BEFORE they open. Olives: after harvest. Never on open blossom.

Targets — pests

Not recorded — the field is blank rather than guessed.

Targets — diseases

Peach leaf curl, Blight, Olive peacock spot, Bacterial canker, Downy mildew, Scab

Supplies: Bordeaux mixture (copper), 5 L pressure sprayer, Gloves and mask

Days to harvest after spraying: 7

Best months: November, December, January, February

Cautions

Copper never breaks down - it accumulates in soil permanently and at high loads harms earthworms and beneficial soil fungi. EU organic rules cap it at 4 kg copper per hectare per year. Treat it as a scheduled winter tool, not a general-purpose spray.

The thing people get wrong

Timing beats dose entirely. A copper spray applied after the peach leaves have curled is wasted money and wasted soil - the fungus entered the bud months earlier. Put the two dates in the calendar and never spray it reactively.