Want to grow sweet, meaty tomatoes? Apply potassium - fertilizer for tomatoes ⋆ 👨‍🌾 Farmer-online ⋆

Like all living things, tomato plants need constant replenishment of nutrients. Their composition is distinguished by a variety of chemical elements, each of which, both by itself and in combination with other elements, is responsible for the vital activity of the whole organism: growth, flowering, fruit setting and their ripening.

The lack or excess of any of the nutrients adversely affects the condition of the plant, leads to the development of diseases and even to its death. Potassium is one of the main nutrients, which is why it is so important that the plant receives it in a timely manner and in the required quantities.

Why do tomatoes need potassium?

Potassium determines both the appearance of the tomato bush, the survival rate of seedlings, fruit set, and the commercial and taste qualities of the crop:

fruit taste;
dry matter content;
ripening uniformity.

A lack of potassium weakens the plant, which contributes to the development of diseases.

Potassium deficiency in tomatoes – how to understand

Tomato plants immediately react to a lack of potassium with their appearance:

growth and the number of ovaries slow down;
the bush looks drooping, the leaves are sluggish;
the tip of the sheet dries out, the border spreads along the entire edge of the sheet, turns brown, twists into a tube;
fruits do not ripen for a long time or have immature areas in the region of the stalk.

When to supplement with potassium

The first application of potassium should be made to the main dressing in the spring a week before planting seedlings in the ground. During the growing season of a tomato, at least four potassium supplements are recommended. For example, root fertilizing with monophosphate can be done as follows:

Feeding seedlings with a solution of 7-10 g of fertilizer per 10 liters of water:

1 – in phase 2 of true leaves;
2 – 10-14 days after landing in the ground;
then the concentration of the solution is increased – 7,5-15 g per 10 liters of water:
3 – the beginning of fruiting;
4 – 10-14 days after the previous one.

Additional top dressing may be required after prolonged rains, which contribute to the leaching of potassium.

Tomato also affects the number of dressings:

bush type;
ripening period;
maturation period;
soil type;
weather;
general condition of the plant.

How to apply potash fertilizers correctly

The main thing in top dressing is not to harm the plant, so you need:

Strictly follow the fertilizer consumption rates and manufacturer’s recommendations.
Fertilize in moderately warm weather, cloudy, but not wet.
The event is best held in the evening or early in the morning.
Top dressing is carried out on well-moistened soil to prevent burns of the root system.
The solution is poured onto the ground carefully, without spraying the leaves and trunk.
Do not use cold solutions.
The remains of fertilizers when top dressing are washed off with clean water.

Potash fertilizers for tomatoes

Potassium monophosphate (KH₂PO₄), a complex mineral fertilizer, in its composition contains K-28%, P-23% in the active substance. Available in the form of powder or granules, the color is beige or light brown. It has positive characteristics and some limitations:

It does not accumulate in the soil, quickly decomposes, so it is not recommended to apply it to the autumn dressing.
Easily absorbed by all parts of the plant, therefore very effective for foliar feeding.
The drug is easily soluble in water, but the solubility is significantly affected by the ambient temperature. At low temperatures, it is poorly soluble and absorbed by plants.
A good ratio of phosphorus and potassium significantly improves the general condition, fruiting, increases resistance not only to various diseases, but also to low temperatures.
Does not contain ballast substances that can lead to side effects.
It has a good effect on beneficial microflora.
Virtually no effect on soil acidity.
Can be used together with pesticides.

Potassium monophosphate contributes not only to abundant flowering and fruit formation, but also to increased formation of side shoots, tillering, which is not very useful for indeterminate tomato varieties.

It quickly loses its qualities under the influence of moisture and light, requires storage in a closed form. Ready-made solutions must be used immediately.

Feeding seedlings with a solution of 7-10 g of fertilizer per 10 liters of water:

1 – in phase 2 of true leaves;
2 – 10-14 days after landing in the ground;
Further, the concentration of the solution is increased – 7,5-15 g per 10 liters of water:
3 – the beginning of fruiting
4 – 10-14 days after the previous one.

Potassium nitrate or potassium nitrate KNO₃ Available in the form of a crystalline salt of white or yellowish color. This is a complex fertilizer containing a convenient ratio of the active substance potassium and nitrogen (K₂O – 46,2, N – 13,7), which usually do not combine well when absorbed by plants:

dissolves well in water;
has an almost neutral PH;
is the prevention of vertex rot and other diseases;
safe for living organisms.

Potassium nitrate consumption rates are usually indicated by the manufacturer and are:

foliar top dressing – 0,5-2% aqueous solution;
watering – per 1 m² area with a solution of 10-20 g per 10 liters of water.

It is most rational to use this fertilizer for top dressing during the period of fruit formation, when the nitrogen application rate needs to be reduced, and potassium should be increased.

Thus, the power of the plant is directed to increase the yield. Repeated top dressing is carried out with an interval of 7-12 days.

Potassium magnesia is a potassium-magnesium fertilizer (K₂SO₄-to and MgSO4 – about 10%) are not used regularly, but with symptoms of magnesium deficiency. It allows you to simultaneously replenish potassium reserves and eliminate the deficiency of the microelement, in which tomato leaf blades between the veins are affected. The color changes from yellow to purple. This greatly impairs photosynthesis. The composition of potassium magnesia also contains about 17% sulfur and from 1 to 3% chlorine.

Advice! A slight concentration of chlorine will not harm the plant with a single application of fertilizer.

Nutrients do not migrate in the soil and are comprehensively absorbed by the root system. They are used in the form of an aqueous solution of 20-30 g per 10 liters, and for foliar feeding they spend up to 5 liters per one hundred square meters.

The use of potassium in the composition of complex fertilizers

Since plants, most often, require not one, but several batteries at the same time, it is more expedient to use ready-made complex fertilizers for top dressing. On the packaging, the manufacturer indicates the content of the elements and the average norms for feeding.

Potassium sulphate or potassium sulfate (K₂SO4)

Effective for soils with an alkaline environment, as it acidifies it. Acidic soils when using potassium sulfate will need to be deoxidized, which is not advisable.

Potassium sulfate can be used in the production of vegetables for all types of soils with normal acidity.

Composition of the active substance: K – 50%, S – 46%, P – 4%. Most often, fertilizer is used as an aqueous solution of low concentrations (about 0,1%) when irrigating under the root. It is not recommended to constantly use potassium sulfate for feeding tomatoes; it should be alternated with other sources of potassium.

potassium humate

The main active ingredient of the fertilizer is humic acids (up to 80%), which have a positive effect both on plant growth and on improving the chemical composition of the soil and its structure. The composition of potassium humate also includes other trace elements that have a beneficial effect on tomato plants in different periods:

soaking seeds (20 ml per 200 g of water) for a day;
three times watering under the root during the growing season (50 ml per 10 l of water) or on the leaves;
for digging the soil (500 ml per bucket of water).

Ammofosca

This is a complex of nutrients ((NH₄)₂SO₄ + (NH₄)₂HPO₄ +K₂SO₄), containing in equal proportions (about 15%) N, K, R. It is produced in the form of granules, does not cake, is used on all types of soils and, practically, for all plants. It is recommended to apply in the form of dressings in the amount of 25-30 g per 1 m² in the flowering stage and the period of fruit formation, as well as when planting seedlings.

It is not advisable to apply in the fall. Top dressing can be supplemented with manure extract, manganese sulfate and boric acid.

Nitrophoska.

Apply when planting seedlings for the main dressing or in the holes, as well as a week after the engraftment of seedlings. Manufacturers offer different percentages of NPK for different crops.

More often the main elements are contained in equal proportions (16:16:16). If the composition of nitrophoska is higher than nitrogen (up to 50%), this contributes to enhanced plant growth and its strengthening in the initial period. phosphorus and potassium occupy in the structure from 16 to 24% and are in equal proportions. Nitrogen is present in an easily accessible form and is used first, and potassium and phosphorus are actively absorbed by the time of flowering.

Potassium for plants from natural sources

Ash.

An excellent natural source of potassium is the ash from burning wood and plant residues. Depending on the material to be burned, the K content can vary significantly:

peat – no more than 3%;
spruce firewood – 5%;
straw, plant residues (buckwheat, sunflower) – up to 30%;
birch, pine firewood – up to 40%.

In addition to potassium, ash contains phosphorus and various trace elements. They bring it both under the digging of the soil, and in dry form, pouring it under a bush. In addition, ash extracts or decoctions (300 g per 10 liters of water) are used for watering or spraying on the leaves. These top dressings can be independent or supplement mineral and organic fertilizers.

cement dust.

Cement dust is also quite safe, and, at the same time, an effective fertilizer, since potassium is up to 30% in the active substance.

At the same time, the dust does not contain chlorine, is highly soluble in water and has an alkaline reaction, which is very useful for acidic soils.

How to feed tomatoes with potassium humate fertilizer, the rules for its preparation – about this in the video.

We prepare mixtures of fertilizers with potassium with our own hands

To feed tomatoes, you can independently prepare various mixtures of several components, taking into account the needs of plants.

For a solution of 10 liters of water:

Potassium sulfate – 15 g, superphosphate – 20 g, ammonium nitrate – 15 g.
Nitroammophoska – 10 g, potassium magnesia – 10 g, superphosphate – 20 g, ash – 150 g.
Mullein infusion – 1 l, wood ash – 1 glass, double superphosphate – 20 g.

The solution is used for irrigation and spent on 1 bush from 0,5 to 1,5 liters.
The optimal use of mineral fertilizers in the cultivation of tomato will allow you to grow a rich crop with good marketable and gustatory qualities. Potassium is indispensable in this production, it cannot be replaced by any other element.