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Get the mixing wrong, and your garden spray can burn foliage—and put you at risk. For one hand-sprayer batch, use 10 litres of water, 100 grams copper sulfate, and 100 grams lime. Prepare them separately. Dissolve copper sulfate in some water. Prepare the lime exactly as its label directs; quicklime reacts strongly with water. In a second non-metal container, add the copper sulfate solution slowly into the lime mixture while stirring. Never reverse that order, and never use metal. Before filling your sprayer, wear gloves, protective clothing, and eye protection. Keep it off skin and eyes, and keep people, pets, and food away. Use the fresh mixture immediately; do not store it. Spray plant surfaces evenly, without heavy runoff, on a calm, dry day, following the crop label and local guidance. Remember: a 1% Bordeaux mixture is 100 grams each in 10 litres—mixed safely and sprayed fresh.