![]() The hydrated lime should be fresh and not carbonated by prolonged exposure to air. Use only good quality hydrated lime (calcium hydroxide). Don’t use lime from last season, and purchase only what you can use in the current season. The most important point is to use fresh lime. You can use either dry hydrated lime or slaked lime to prepare Bordeaux. Fixed copper fungicides shouldn’t be used in making up a Bordeaux mixture. If it gets moist, it becomes lumpy and difficult to work with. Ordinary, lump copper sulfate isn’t satisfactory, because it is slow to mix into the solution. Powdered copper sulfate, often referred to as “bluestone,” is a finely ground material that dissolves relatively quickly in warm water. You can purchase copper sulfate and hydrated lime at most garden centers. Thus a 10-10-100 Bordeaux mixture would be comprised of 10 pounds of copper sulfate, 10 pounds of lime, and 100 gallons of water.Ī more manageable amount for the home gardener would be a 1-gallon mixture of 10-10-100 Bordeaux, which would contain 1/10th of a pound of each of the dry ingredients, which would be 3 1/3 tablespoons of copper sulfate and 10 tablespoons of dry hydrated lime in 1 gallon of water. The first number refers to pounds of copper sulfate, the second to pounds of dry hydrated lime, and the third to the total gallons of water. The three hyphenated numbers represent the amount of each material to add. Takes longer, requires more knowledge to prepare, safety equipment requiredġEffectiveness is a function of coverage, timing, and concentration.Īlthough there are many formulas for preparing Bordeaux mixture, generally a ratio of 10-10-100 works well for many disease-causing pathogens. High pH, leaves a salty deposit, more phytotoxic Longer lasting, more active, stains surfaces Advantages and Disadvantages of Fixed Copper Sprays and Bordeaux Mixture. Advantages and disadvantages of fixed copper and Bordeaux sprays are compared in Table 1.īordeaux mixture is commercially available in premixed packages, but freshly made Bordeaux sticks and weathers better on trees. With all Bordeaux and fixed copper sprays, thorough coverage is essential to give plants the desired protection from disease-causing pathogens. However, they are the most effective and best choice to use in spring after trees begin to show new growth. Although fixed copper sprays are much easier to prepare and don’t stain surfaces, they don’t withstand winter rains as successfully. tribasic copper sulfate, copper oxychloride sulfate, and cupric hydroxide) also control many of the same disease-causing organisms as Bordeaux mixture. Downy mildew and powdery mildew on grapes īecause Bordeaux can leave a blue-green discoloration on plants or painted surfaces, use it on dormant, deciduous plants that are away from buildings and fences.įixed copper fungicide sprays (e.g.Leaf curl and shot hole on peaches and nectarines.Applying Bordeaux after trees break dormancy generally isn’t recommended, because it can injure leaves.Īmong Bordeaux’s many uses are applications in fall and winter to manage: The ability of Bordeaux mixture to adhere to plants in rainy weather makes it an excellent choice for a winter fungicide. These natural minerals, when mixed in the correct order, provide long-lasting protection to plants against diseases. Bordeaux mixture-a combination of copper sulfate, lime, and water-is an effective fungicide and bactericide that has been used for decades to control diseases of fruit and nut trees, vine fruits, and ornamental plants.
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