Bordeaux Mixture Apr 2026

Separate concentrated solutions of copper sulfate and lime are prepared in non-metallic containers. These are then diluted and combined in a spray tank.

Bordeaux mixture is one of the most historically significant fungicides in agriculture, consisting of a combination of , quicklime (calcium oxide) or slaked lime , and water . First developed in 1882 by French botanist Pierre-Marie-Alexis Millardet to combat downy mildew in vineyards, it remains a staple in both conventional and organic farming due to its efficacy and low cost. Core Components & Chemical Composition bordeaux mixture

A common formulation is the 4-4-50 mixture, meaning 4 lbs of copper sulfate and 4 lbs of lime in 50 gallons of water. Separate concentrated solutions of copper sulfate and lime

Pulverized copper sulfate and hydrated lime are added directly to a filling spray tank while the agitator is running to ensure even mixing. The final solution must be neutral or slightly

The final solution must be neutral or slightly alkaline (

); acidic mixtures are phytotoxic and can burn plant foliage.