1 Dissolve 100 gram of builders’ (hydrated) lime in half a standard (plastic) bucket of water. (About 5 litres).
2 Dissolve 100 grams copper sulphate (available at garden centres) in a separate half bucket of water.
3 Keeping the lime mixture agitated to prevent settling, pour it steadily into the half bucket of dissolved copper sulphate.
4 If necessary add enough extra water to make up a total of 10 litres. This is Bordeaux mixture. It is at its most effective strength when freshly mixed so must be used immediately or within a couple of days.
5 It is sprayed to completely cover the main (bare) branches of peach, nectarine and other stone fruit trees to help control leaf curl and brown rot disease. It is also sprayed over raspberry canes in late July for control of raspberry rust.
Bordeaux mixture colours the sprayed plants blue. The spray can withstand light rain. However a disadvantage with this mixture is that it tends to quickly settle so must be constantly agitated during spraying operations. The lime content also tends to easily block the fine nozzles of sprayers.
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