Bordeaux Liquid In Horticulture. Composition. How To Cook. Application

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Bordeaux Liquid In Horticulture. Composition. How To Cook. Application
Bordeaux Liquid In Horticulture. Composition. How To Cook. Application

Video: Bordeaux Liquid In Horticulture. Composition. How To Cook. Application

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Video: Bordeaux Mixture Preparation: Preventive Spray for black spot & other plant diseases 2023, January

Like many great discoveries, the use of copper sulfate for processing plants was made possible by chance. First noted the positive effects of copper compounds on plants, in this case potatoes, in Ireland. From the then still unknown disease, especially in humid weather, potato plantings perished everywhere, and only near copper plants did this culture continue to grow normally. Observant gardeners began to use copper waste in the processing of this crop, saving crops from the Irish weather.

The second chance encounter with the result of a chemical reaction between copper sulfate and lime took place in the late 19th century in the French province of Bordeaux. In the fight against mildew, which was destroying the vineyard in the vineyard, one of the winegrowers, regretting to throw away the remains of solutions of copper sulfate and lime, which he used to treat the bushes, poured them into one container and sprinkled the grapes. The result was very favorable.

With the light hand of the winegrower, the observation of Irish gardeners and the perseverance of the French botanist P. Millard, a simple but effective remedy for combating diseases of almost all vegetable and horticultural crops appeared. The number of diseases from which Bordeaux liquid protects plants is about 25 items. Basically, these are infectious diseases of a fungal and bacterial nature.

The use of Bordeaux liquid in the garden
The use of Bordeaux liquid in the garden

How to avoid mistakes when preparing Bordeaux liquid?

For more than a hundred years, copper sulfate and lime have been used to prepare a solution called Bordeaux liquid. This medicinal solution has not received a single negative response and is successfully used both on an industrial scale and in private households. For the sake of fairness, it should be noted that often there are notes about low efficiency or, conversely, about the death of crops from burns. Why do such cases happen?

It is very likely that the following mistakes were made in the preparation of Bordeaux liquid:

  • the ratio of the components is broken;
  • each component is incorrectly diluted;
  • the connection of the components into a single solution was incorrect;
  • accidentally or due to ignorance, organophosphorus substances incompatible with the Bordeaux liquid, malofos and other alkaline or acidic preparations were added to the tank mixture.

What you need to know to use Bordeaux liquid correctly?

When buying a ready-made mixture for the preparation of Bordeaux liquid, you need to pay attention to the label and ask the seller what it means:

Sometimes the label says CuSO₄ without explanation. It is known that copper sulfate is a white substance. Copper sulfate is a substance of blue or blue color, soluble in water. The formula of copper sulfate is different, it is represented by the pentahydrate CuSO₄ * 5H 2 O. In a dense package, the color is not visible, and there is no verbal written explanation on the label.

What is packed in the second package is also unknown. Only the designation is written - lime. What kind of lime? It must be indicated whether it is extinguished or not. It should be written: lump quicklime, ground quicklime or ground quicklime boiled water. If it says fluff, it means that the lime has passed the slaking procedure. It is enough to dilute fluff lime in excess of water and get the desired milk of lime.

To obtain high-quality Bordeaux liquid, milk of lime is prepared from freshly slaked lime. Therefore, they often write lime on the label, implying (guess, they say, yourself) a boil to be extinguished.

It should be taken into account that when preparing a solution of Bordeaux liquid from quicklime, the mass (weight) of the latter must be greater than that of copper sulfate. This is due to the presence of insoluble impurities in the starting material or poor quality boiling lime due to prolonged storage in unsuitable conditions. If the fluff lime is of high quality, freshly prepared, the ratio of the components by weight is 1: 1. It is the lack of confidence in the quality of this component that can explain the predominant amount of lime on the labels of the mixture sold.

Copper sulfate pentahydrate (Copper sulfate) for obtaining Bordeaux liquid
Copper sulfate pentahydrate (Copper sulfate) for obtaining Bordeaux liquid

Cooking Bordeaux liquid correctly

A brief introduction to the components of the Bordeaux mixture

Bordeaux mixture consists of 2 components:

Copper sulfate salt, in other names - copper sulfate. Copper sulfate, or crystalline hydrate (pentahydrate) of copper sulfate (CuSO₄ * 5H 2 O) - this substance is represented by blue-blue crystals, readily soluble in water to obtain an acidic medium (pH <7).

Not to be confused with copper sulfate. Copper sulphate (CuSO₄) is a colorless chemical, hygroscopic, easily forms blue or blue crystalline hydrates. Crystalline hydrates are readily soluble in water.

Calcium oxide, or quicklime, belongs to the main oxides. Its chemical formula is CaO.

When preparing Bordeaux liquid, the third component is water:

Calcium oxide (CaO) reacts vigorously with water. As a result, calcium hydroxide Ca (OH) 2 is formed and heat is released. This reaction is called lime slaking.

Calcium hydroxide is called slaked lime, or fluff lime. The substance is a strong base, therefore its solutions are alkaline. Fluff is a white powder, poorly soluble in water. When mixed with a large amount of water, it forms a suspension or a suspension of calcium hydroxide in water, in everyday life called milk of lime (milk).

Preparing dishes and other products

For the preparation of Bordeaux liquid, it is necessary to prepare enameled containers, without chips or cracks, wooden, glass, and clay. It is not recommended to use plastic, iron, aluminum dishes. When dissolved, a reaction takes place with the release of a large amount of heat (lime slaking), with the formation of an acidic solution, which can react with a galvanized or iron container (with dissolution of copper sulfate).

To dissolve the components of Bordeaux liquid, you need:

  • 2 buckets for 5 and 10 liters;
  • a piece of gauze and a sieve for filtering solutions;
  • wooden stick for stirring solutions;
  • litmus graduated paper strips or an iron nail to determine the neutrality of the resulting solution;
  • kitchen scales, if you prepare the Bordeaux liquid solution yourself.

Step-by-step instructions for preparing a solution of Bordeaux liquid

In the store you can buy a ready-made mixture, packaged in separate bags with quicklime (CaO) and copper sulfate (CuSO₄ * 5H 2 O). It is necessary to clarify with the seller which components are in the sold mixture.

Dissolving copper sulfate:

  • pour 1-2 liters of hot water into a 5 liter bucket;
  • carefully pour out the package or weight measure of copper sulfate.
  • mix thoroughly with a wooden stick until completely dissolved;
  • add gradually to the solution, stirring constantly, up to 5 liters of cold water.

Table 1 shows weight measures for the preparation of Bordeaux liquid of different percentages using quicklime and slaked lime

Set aside the prepared solution of copper sulfate. If you are interested, you can determine the acidity of the solution with a graduated litmus strip (it should be less than 7 units).

We proceed to the preparation of milk of lime (slaked lime solution). Slaked lime is a strong base, it has an alkaline reaction. When the solutions are combined, slaked lime neutralizes the acidity of the copper sulfate solution. If this procedure is carried out poorly, the plants will get burned during processing and may even die (especially young ones).

Extinguish lime:

  • pour 2 liters of cold (not hot) water into a 10 liter enamel bucket;
  • fall asleep a measure of quicklime;
  • mix thoroughly while extinguishing is in progress;
  • if slaked lime is used, we simply prepare a solution of the appropriate concentration (Table 1);
  • at the end of the reaction, slaked lime or calcium hydroxide Ca (OH) 2 is formed;
  • add 3 liters of cold water to the cooled solution of slaked lime while stirring; in total there should be 5 liters of milk of lime.
Prepared solution of Bordeaux liquid
Prepared solution of Bordeaux liquid

Table 1. Weight quantities of components for the preparation of 10 liters of Bordeaux liquid

Concentration, %

Components for 10 liters of water, g
copper sulfate

CuSO₄ * 5H 2 O

slaked lime

Ca (OH) 2



0.5-0.7 50 75 100
1.0 100 100 150
2.0 200 250 300
3.0 300 400 450
5.0 500 600 650

We start mixing solutions

  • Both solutions must be cold before mixing.
  • From a 5 liter bucket, a solution of copper sulfate in a thin stream, stirring constantly, pour into the solution of milk of lime (not vice versa).
  • We get 10 liters of a mixture of 2 solutions.
  • We check the acidity. If a solution of Bordeaux liquid is prepared correctly, the iron nail dipped into it will not be covered with a copper coating, and the litmus strip will show 7 units.

If the Bordeaux liquid solution turns out to be acidic, it is neutralized with milk of lime (prepared additionally) to a neutrality indicator pH = 7-7.2 units.

With additional deoxidation of the prepared solution, it is already possible to pour lime milk into the Bordeaux liquid solution, but still in a thin stream, constantly stirring with a wooden stick.

The resulting neutral solution of Bordeaux liquid is filtered through a fine sieve or gauze folded in 4-5 layers.

The prepared Bordeaux liquid solution is not subject to long-term storage. After 1-3 hours of settling of the prepared solution, they begin to process the plants.

The remainder of the Bordeaux liquid can be stored for no more than a day by adding 5-10 g of sugar to 10 liters of solution.

The principle of action of Bordeaux liquid

A solution of copper sulfate is a fungicide. The solution is in good contact with plant organs (leaves, bark). A properly prepared solution is practically not washed off by rain.

Copper compounds in the Bordeaux liquid are poorly soluble in water and, when sprayed on plants, settle in the form of microscopic crystals on the leaves and stems of plants. Copper ions destroy the protective shells of the spores and the mycelium itself. The fungus dies. The aggressive action of copper on trees and shrubs softens the lime solution in the preparation and at the same time acts as an adhesive.

The effectiveness of Bordeaux liquid increases with finely dispersed spraying of plants.

The duration of the fungicide is up to 1 month. Effectively suppresses pathogens of pathogenic microflora of a fungal-microbial nature.

Application of Bordeaux liquid
Application of Bordeaux liquid

Be careful

  • Large drops of Bordeaux liquid are phytotoxic to plants, especially during the growing season.
  • The Bordeaux liquid solution flowing down from the leaves to the soil contributes to the accumulation of copper in it, which negatively affects the crops grown (causes the leaves and ovaries to fall off).
  • Repeated use of Bordeaux liquid without observing the recommended processing times for plants during the growing season can cause their death.
  • It makes no sense to add soap to Bordeaux liquid. From its addition, contact with plants will only decrease.
  • Bordeaux liquid is incompatible in tank mixes with other drugs. Colloidal sulfur is an exception.

The period of processing plants with Bordeaux liquid

Perennial horticultural crops are sprayed with solutions of Bordeaux liquid of 2-3% concentration:

  • before bud break (approximately in February-March);
  • in late autumn after complete leaf litter (approximately October - early November);
  • during the growing season, starting from the green cone phase of perennial crops and planting garden plants, spraying with 1-0.5% solution is carried out according to the recommendations;
  • the processing of plants that is not foreseen by the timing is carried out in case of an obvious disease due to weather conditions, epiphytotic infection.

Protecting plants from diseases with Bordeaux liquid

When processing plants, copper in a solution of Bordeaux liquid is a poison for fungal diseases, and lime is a neutralizer to remove the burn effect of acid on the plant.

Table 2 provides a list of crops and diseases. The main phases of the treatment with Bordeaux liquid are described. A more detailed description of diseases and protection measures can be found on the corresponding sites.

Table 2. Protection of horticultural and vegetable crops from diseases using Bordeaux liquid

Culture groups Diseases Processing period
Perennial fruit crops
Pome fruits: pears, apple trees, quince Fruit rot, leaf rust, scab, phylostictosis, moniliosis, black crayfish, powdery mildew, leaf spots. Before the beginning of the spring growing season and after the leaves have completely fallen off, the plants are treated with a 3% solution of Bordeaux liquid.

During the growing season: in the bud extension phase and after flowering, spray with 1% Bordeaux liquid solution.

The rest of the time - as needed.

Stop processing 2 weeks before harvesting.

Stone fruits: cherries, cherries, plums, cherry plums, peaches, apricots Coccomycosis, leaf curl, moniliosis, clasterosporiasis. Before the beginning of the spring growing season and after the leaves have completely fallen off, the plants are treated with a 3% solution of Bordeaux liquid.

From the budding phase to the beginning of flowering and in the phase of the onset of ovary growth, they switch to spraying with a 1% solution of Bordeaux liquid.

Apricots and cherries are highly sensitive to Bordeaux liquid (deformation and cracking of the fruit is observed). It is better to treat them with a 0.5% solution of Bordeaux liquid.

Stop processing 2 weeks before harvesting.

For more details see the article "Summer diseases of berry and fruit crops"

Berry crops
Grapes Mildew (downy mildew), anthracnose, black rot, rubella, cercosporosis, melanosis.

The bushes are treated with Bordeaux liquid in the phase of leaf deployment and during the growing season once every 2-3 weeks in order to prevent and from other concomitant infections.

For more details, see the article "Protection of grapes from fungal diseases"

Gooseberries, raspberries, currants, blackberries, wild strawberries and strawberries Leaf spot, leaf rust, anthracnose, septoria, black rot. Berry growers have a shorter growing season, therefore, during the season, 2-3 treatments are carried out with a 1% solution of Bordeaux liquid before bud break and before flowering begins. The third treatment is carried out mainly after harvesting.

For more details see the article "Summer diseases of berry and fruit crops"

Main garden crops
Cucumbers, zucchini, pumpkins, beans, tomatoes, cabbage, onions, garlic, peppers, eggplants, potatoes True and downy mildew, root and root rot of seedlings and adult plants, fusarium wilting, anthracnose, late blight. For the first time, seedless vegetable crops are sprayed with Bordeaux liquid in order to prevent fungal diseases in the phase of mass germination. The second spraying is carried out with the deployment of 2 - 3 true leaves.

On seedlings, the first spraying with Bordeaux liquid is carried out 2 weeks after planting.

For processing plants, use a 0.5-1% solution of Bordeaux liquid.

In the subsequent growing season, spraying with Bordeaux liquid is carried out according to the recommendations and at the first manifestations of the disease.

Dear Readers ! The article focuses on the correct preparation of Bordeaux liquid, which determines the effectiveness of the drug's effect on fungal diseases of berry and garden and vegetable crops. More extensive information on the use of Bordeaux liquid for plant protection, related to their growth and development, formation and harvesting characteristics, can be found in the articles on the care of specific plants on our website.

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