What Is A Bordeaux Fungicide: Making Bordeaux Mixture Fungicides

Bordeaux Fungicide is a simple mixture of water, lime and copper sulfate. In addition to being an effective fungicide, it is also a bactericide.

This traditional mixture is very effective for ornamental plants, vine fruits, fruit trees, and nut trees.

bordeaux fungicidePin

When mixed and applied correctly, it provides lasting protection against various plant diseases. 

What Does Bordeaux Fungicide Combat? 

This mixture provides a very effective defense against fungal diseases such as: 

It makes an excellent dormant season treatment for trees because it can adhere to the surfaces of the treated trees and stay in place, even in the rain, snow, and other inclement weather. 

How Do You Make Bordeaux Fungicide?

To make a small batch, you’ll need:

  • Non-metal containers, stirring implements, and other tools
  • Dust mask to prevent inhalation of particles
  • Vinegar for washing your tools

You’ll also need:

  • 3 1/3 tablespoonfuls of copper sulfate
  • 10 tablespoonfuls of hydrated lime
  • One gallon of water

Don’t make more than you can use immediately. This mixture does not store well. If you must wait a few days before spraying, keep the mixed ingredients separate until the last moment. 

Note: Keep all individual ingredients and equipment well out of the reach of children. This is a very corrosive product. 

If you only make a small amount to be hand sprayed, you will want to mix the water and copper sulfate in one plastic or glass container using a plastic or wooden stirring implement.

Remember to sift the copper sulfate through a non-metal screen. 

Quickly mix the hydrated lime and water in a separate plastic or glass container using a plastic or wooden stirring implement.

Pour it into the copper sulfate and water mixture, stirring gently and continuously. 

Pour the resulting mixture into your hand sprayer. Rinse your containers and stirring implements thoroughly (a minimum of three times).

Add vinegar to the final rinse to neutralize the residue.

After applying this mixture to your plants, wash your sprayer in the same manner.

Multiply Amounts For Larger Batches

To create the mix in your sprayer, slowly run the water into the sprayer tank with the mechanical agitator running.

When it is about a third full, add the copper sulfate by washing it through a screen or filter as you continue to add water and keep the mixture agitating.

Stop adding water when you have used 2/3 of the water.

In a plastic or glass container, mix the hydrated lime into the remaining water using a plastic or wooden stirring implement.

Slowly pour this mixture into your sprayer tank and allow the agitator to mix it in.

How & When Do You Apply Bordeaux Fungicide? 

Apply once in the autumn and again in the spring. Wear protective gear (e.g., goggles, mask, long sleeves, and gloves) to prevent coming into contact with this product, as it can be irritating and stain your skin blue.

Wash up thoroughly after applying the fungicide and cleaning your equipment. 

You can use the recipe above for both fall and springtime use; however, for the most durable wintertime results, use a slightly more potent mixture in the fall:

  • 1 ½ quart of copper sulfate mixture
  • 1 ½ quart of hydrated lime mixture
  • 2 gallons of water

Follow this up with a slightly weaker mixture in the springtime: 

  • 1 pint of copper sulfate mixture
  • 1 pint of hydrated lime mixture
  • 2 gallons of water

This will be gentler on tender new leaves and buds.

Where Can You Get The Ingredients? 

Check local garden centers or online to find the ingredients affordably and in bulk.

If you feel unsure about doing it, you can purchase a prepared mixture.

If you are not using a great deal, buy only small amounts of the ingredients (especially the lime) as they will not keep well from one season to the next.

Bordeaux Mixture Preparation

Preventive Spray For Black Spot & Other Plant Diseases

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