Top dressing of tomatoes boric acid


When growing tomatoes it is difficult to do without the use of various types of fertilizing, because this culture is quite demanding on the presence of nutrients in the soil. In recent years, gardeners have often begun to recall recipes that have come down from the “grandmother's” times, when the modern diversity of fertilizers did not yet exist and used reliable, time-tested formulations. One of such substances is boric acid, which is used not only in medicine, but also in gardening, and its scope is quite wide.

At least, fertilizing tomatoes with boric acid was actively used in the last century and gave excellent results, especially in the southern regions, where high temperatures during the flowering of tomatoes are far from uncommon. Also universally applied this substance against insects and against various fungal diseases.

Bor and his role in plant life

The importance of such a trace element as boron in plant life is difficult to overestimate. After all, he is a direct participant in the process of cell formation and nucleic acid synthesis. In addition, boron accelerates some vital processes occurring in plant organs.

Important! First of all, boron is necessary for the normal functioning of the youngest parts of the plant, that is, growing points, ovaries and flowers. Therefore, it is from them that the problems begin in plants, including tomatoes, in the absence of this element.

Signs of boron deficiency

The lack of boron usually leads to the accumulation of toxic substances in the plant tissues of tomatoes, which cause poisoning of the plants. The following symptoms may occur:

  • If the boron deficiency is still insignificant, then on tomato bushes everything will start with the fall of buds and ovaries, and poor fruit formation.
  • At the next stage, the curvature of the apical young shoots and discoloration of the leaves at the base of these shoots is possible. And the top itself can still be green for some time.
  • Further, all young leaves begin to curl from top to bottom, and their color becomes whitish or light green.
  • In the last stage, the veins of the affected leaves darken, the growth points die off, the leaves and stems become very fragile at the fold. If the tomatoes already have fruit, then dark spots appear on them.
Attention! Boron deficiency can be aggravated if excessive amounts of nitrogen fertilizers and lime have been applied.

In addition, the lack of boron content in tomatoes can lead to oppression and rotting of the roots, a general lag in growth and development. Boron deficiency also provokes the development of some diseases - gray and brown rot, bacteriosis.

Attention! The boron deficiency is especially pronounced in dry and hot weather.

And in the absence of obvious signs of deficiency of this element, many gardeners write off the lack of a tomato harvest for adverse weather conditions. While it would be enough to spend a few preventive supplements boron, and everything would be fine.

It is also important to keep in mind the signs of an excess of boron on tomatoes in order to be able to stop in time in an attempt to rectify the situation with supplements. If boron in tomatoes is more than necessary for normal plant life, then signs, on the contrary, appear first on the lower old leaves. In this case, small brown spots are formed on them, which increase in size until it leads to the complete death of the leaf. The leaves themselves, in addition, often become dome-shaped, and their edges are wrapped inside.

Boric acid and its effect on tomatoes

Boric acid is the most affordable chemical compound of boron found in our life. It is a colorless, crystalline powder that is colorless and odorless, non-toxic and cannot be a hazard to human skin. But once inside the human body, it can not be bred by the kidneys and will accumulate and poison it. Therefore, when using an acid solution, care must be taken.

Comment! Boric acid crystals usually dissolve well in water. The acidic properties of the resulting solution are very weak.

Boric acid solution has long been used to feed tomatoes, and its effect on tomato bushes is very diverse.

  • A positive effect on the formation of ovaries and stimulates the flowering of tomatoes, thereby increasing the yield.
  • Accelerates the ripening of tomatoes, which is important for areas with unstable weather conditions.
  • It improves the absorption of nitrogen and, thereby, accelerates the formation of new stems, leaf development.
  • Stimulates the development of the root system, therefore, increases the ability to absorb various useful elements.
  • Increases resistance of tomatoes to various adverse conditions.
  • It improves the quality of the tomatoes themselves: their sugar content increases, a bright taste is obtained, and the keeping quality of the fruits increases.

It is also necessary to note the fungicidal properties of boric acid. Processing it helps tomatoes escape from the development of phytophthora, which is the most insidious and common disease of solanaceous crops, especially in open ground.

Important! Since boron does not have the ability to move from old leaves to young ones, its use in dressing is necessary during the entire vegetative period of plants.

Methods of using boric acid

Boric acid solution can be used to feed tomatoes at various stages of development, starting from the seed treatment stage.

Preparation of the solution

The scheme of preparation of a solution of boric acid with different methods of use is the same - only the proportions that are used in different cases differ.

The fact is that the crystals of this acid best dissolve in water at a temperature of about + 55 ° C- + 60 ° C. Boiling water and cold water will not work. Therefore, you must first thoroughly dissolve the required amount of the substance in a small container with hot water, and then bring the solution to the recommended volume. It is also possible to immediately dissolve boric acid in a large volume of hot water, and then cool it to room temperature, but this is less convenient.

Boric acid for seed and spillage treatment

To speed up the process of germination and more friendly emergence of tomato seedlings, seed soaking is used before planting seedlings in acid solution of the following concentration: 0.2 g of powder is measured for 1 liter of water. In the resulting solution, tomato seeds are soaked for about one day. After soaking, they can immediately be sown in the ground.

Tip! If you plant tomatoes in large quantities, then for convenience of processing instead of soaking, you can powder all the seeds with a mixture of dry boric acid powder and talcum powder in a 50:50 proportion.

A solution of the same concentration (that is, 2 grams per 10 liters of water) can shed the soil before sowing seeds into it or planting seedlings. This is desirable in the event that there is a suspicion that your soil lacks boron. Typically, these are most sod-podzolic soils, marshy or calcareous soils. 10 square meters. meters of beds used 10 liters of solution.

Foliar top dressing

Most often, top dressing uses foliar processing of boric acid. This means that the resulting solution is sprayed the entire bush of tomatoes from top to root. For the preparation of such a solution for 1 liter of water use 1 gram of powder. Since acid is often sold in bags of 10 grams, you can immediately dilute the package in 10 liters of water. It can be convenient in the presence of a large number of tomato bushes.

For prophylactic purposes, it is desirable to conduct foliar feeding of tomatoes with boron three times per season:

  • In the budding phase;
  • In the period of full bloom;
  • During the ripening of the fruit.

Especially important foliar feeding boric acid of tomatoes in the greenhouse.

Important! At temperatures above + 30 ° C, the stigmas of the pistils dry up in tomatoes and pollination does not occur.

Spraying with boron helps tomatoes to overcome the adverse environmental conditions and improve the process of selfing. Therefore, the moment of mass flowering for tomatoes is the most traditional boron for active foliar feeding.

Tip! If on the tomato bushes you notice already obvious signs of a boron deficiency, as described above, then you need to spill a solution of boric acid under the root.

The concentration of the solution - 2 grams per 10 liters.

Finally, foliar top dressing with boron is also used for the prevention of late blight and other fungal diseases. The concentration of the solution in this case is the same as for conventional feeding (10 g per 10 liters). But for maximum effect, it is better to add 25-30 drops of iodine to the solution.


For the cultivation of tomatoes, boric acid is one of the most necessary varieties of top dressing, since it simultaneously serves as a stimulator of flowering and growth and protection against diseases.