Lack and excess of potassium
Potassium is responsible for the formation of fruits. If there is initially little of it in the soil, then during the period of filling the cucumbers, the fruits begin to take the element from the leaves and shoots, so they wither, turn yellow and crumble.
Potassium deficiency in cucumbers can be determined by the pear-shaped shape of the fruit . The stalk is usually narrower and smaller than the cucumber itself. The fruit is often hook-shaped. This is the end product of the grief of gardeners who did not have time to take action. You can prevent deficiency in advance if you notice changes in foliage in time:
- leaves are characterized by edge burn, when a normal green leaf begins to dry out along the edge;
- Old leaves are the first to suffer - they begin to die;
- the green plate turns yellow, and areas with chlorophyll remain only next to the veins;
- with severe potassium deficiency, the leaves are holey and wrinkled;
- young leaves do not grow to their usual size and are cup-shaped.
Video: Signs of nutrient deficiency in plants
In addition to its unusual shape, a cucumber without potassium will be tasteless. Such fruits usually have no aroma.
To feed cucumbers with potassium use:
- wood ash - up to 10 kg per 1 hectare of land ;
- potassium nitrate diluted with water for foliar spraying;
- mullein solution for watering at the root.
In order to urgently eliminate the lack of potassium, it is necessary to resort to watering the plants with a solution of potassium sulfate. Foliar fertilizing with potassium is not very effective. The element is absorbed very slowly by the leaf plate, so you need to save time and the health of the plant.
Manifests itself in the form of necrosis of leaf edges. This happens due to the increased concentration of salts. The nutritional value of fruits decreases because a large amount of potassium delays the entry of other substances into the tissues - calcium, magnesium and other trace elements.
Excess potassium is less noticeable than its deficiency.
Some features of fertilizing cucumbers
During the flowering period, treatments with boric acid - spraying - are appropriate. You need 0.2 g of boric acid per bucket of water and thoroughly spray all the flowers with this solution. A couple of days after this, add potassium sulfate dissolved in water in the amount of a teaspoon per square meter and superphosphate in the same volume, previously dissolved in boiling water.
As for nitroammophoska, many gardeners apply it all season literally at the tip of a teaspoon, they dissolve it in water and spray the plants with this composition in the evening all season, nothing bad usually happens.
It is important to carry out three or four mandatory feedings of cucumbers per season; more is possible, but there is no urgent need for this. It is better to water the plants more often, loosen the soil and fight weeds
Conclusion. Like all living beings, cucumbers need nutrition, balanced and preferably varied. Do not stuff cucumbers with the same fertilizers, do not use large doses of nitrogen fertilizers, try to use more natural fertilizers - for example, weeds, wood ash, soot fermented within a couple of days and then your yields will be high and, most importantly, healthy!
Nitrogen deficiency and excess
Causes growth arrest in melon crops. If the plant does not gain strength and green mass, the fruits will be small in size, with a yellowish skin. With a lack of nitrogen fertilizers, the shape of a cucumber becomes sharper towards the bottom - it has the shape of a carrot and decreases in diameter.
A sign of nitrogen deficiency can be determined by external signs:
- the leaves lighten, then turn yellow;
- old leaves die;
- shoots are weak and yellow.
If cucumbers lack nitrogen in the early stages of the growing season, it will be more difficult to compensate for the deficiency later. The fastest way is to dilute urea and treat the foliage. Repeat every other day until the foliage returns to normal.
From this illustration, you can easily determine what elements cucumbers lack.
Large doses of nitrogen fertilizers can be calculated by the unusually dark color of the leaf blade. At the same time, the absorption of calcium is disrupted, since nitrogen and calcium are antagonists (substances that weaken each other’s properties).
If you constantly water cucumbers with high doses of nitrogen fertilizers, the fruits will be small, because all the energy of the plant will be directed into the growth of green mass.
Green pattern on yellow background
If you observe yellowed leaves with green streaks on your cucumbers, be sure that the plants are experiencing a lack of magnesium, which is why chlorophyll is destroyed in the structure of the above-ground parts of the plants. As a result of a lack of magnesium, plants begin to age quickly and, as a result, bear very little fruit.
To compensate for magnesium deficiency, cucumbers should be fertilized with ash or magnesium sulfate (magnesium sulfate).
Lack and excess of phosphorus
If cucumbers do not have enough phosphorus, the plant does not grow large, even if there is nitrogen in the soil. This happens because the root system does not fully develop, so metabolism in the tissues is difficult.
The main signs by which you can notice a lack of phosphorus:
- change in foliage color from green to purple;
- the appearance of flowers is delayed;
- the process is more noticeable on older leaves.
Without phosphorus, the fruits will be small and tasteless. The nutritional value is reduced because the production of nutrients will be slowed down. The fruit may not reach ripening at all. Ovaries without phosphorus usually fall off during the flowering stage.
Phosphorus is added to the soil in the fall or 2 weeks before planting .
It appears as a general yellowing of the plant. The leaves become covered with brown or yellow spots. Phosphorus deficiency is usually not visible on fruits, but the taste may be impaired - with an excess of phosphorus, the absorption of potassium is also impaired, therefore, cucumbers may taste bitter.
Lack of phosphorus in cucumbers.
Fertilizing of cucumbers is done most effectively by watering. Foliar spraying is not effective, since phosphorus is absorbed 30 times slower .
Fertilizers applied in the fall are enough for cucumbers throughout the entire growing season and fruiting, so you need to try to add phosphorus to the soil in the fall.
Magnesium for cucumbers [Mg]
Excess magnesium
If there is an excess of this microelement, the cucumber's root system dies. The plant does not absorb calcium from the soil well. The leaves begin to darken and curl.
Magnesium deficiency in cucumbers
Magnesium deficiency
If there is a lack of magnesium in the soil, then the cucumber leaves become fragile and look like they are burned. Spots with pale green or yellowish paint appear on the lower leaves. Green color is visible only in places of veins.
Solution
To increase magnesium levels, constant foliar feeding with magnesium nitrate (100 grams/10 liters) is carried out. For fertigation, you can use Nutrivant Drip with magnesium. For crops grown hydroponically, it is recommended to introduce a magnesium solution of 30 mg/liter.
Lack of microelements
Metabolism in plants is complex. An excess of some substances affects the deficiency of others. If there is a shortage of microelements, which are supplied in very small doses, you can lose your harvest. There are 8 main elements, the deficiency of which greatly affects the yield.
Sulfur
A lack of sulfur is similar to a lack of phosphorus: the leaves become rough, change color - brown-lilac spots appear. This threatens the fruits with disease and rotting. Therefore, when growing cucumbers, you can buy microfertilizer additives and use them as needed.
Bor
In addition to the death of leaves and tissue necrosis, the nutritional value of cucumbers decreases. If boron deficiency appears towards the end of ripening, then the problem will not have time to affect the fruit. If at first, then the cucumbers will be small due to lack of nutrition.
Iron
If cucumbers lack iron, this is noticeable in the leaves. The fruits don't show at all. Most likely, the fetus will not have the amount of microelement that should be normal. This does not affect the taste characteristics.
Chlorosis in cucumbers
Magnesium
Magnesium deficiency occurs in acidic soils. It occurs when there is an imbalance of potassium in the soil, that is, when there is a large amount of it. Excess magnesium is poorly tolerated by the plant - its roots die, the plant cannot take food and dies.
Calcium
A lack of calcium has the worst effect on the taste of fruits. Acidic soils create a deficiency. In addition to the watery taste, the fruits are smaller than usual.
Zinc
Zinc deficiency can occur in nitrogen-rich soils. Lack of zinc greatly affects the quality of the fruit: they are ugly in shape, have a thick peel, are bitter and tasteless.
Manganese
Affects breathing and the ability to absorb carbon dioxide. This affects the growth of shoots and fruits. Adequate amounts of manganese help bring out the natural sweetness of cucumbers. Restore the balance by foliar spraying with potassium permanganate.
If there is a lack of manganese, cucumbers are not sweet enough
Molybdenum
The deficiency is more pronounced on marshy soils. If cucumbers grow in lowlands where water often stagnates, the plants will look chlorotic and diseased. In this case, the fruits do not ripen and rot.
Main causes of color loss
When considering possible reasons, you need to take into account that it can be either one reason or several at the same time. If there is a lack of one or another nutritional element, the plant organism’s immunity weakens. He can no longer fight insect pests or pathogens with all his might. That is why it is necessary to track the entire chain of possible pathologies.
The causes of yellowing foliage may be:
- lack of essential microelements for cucumber (nitrogen, potassium, phosphorus);
- inability to absorb microelements;
- lack of sunlight. In this case, the leaf begins to turn yellow from below;
- drying out of the top layers of soil and root system;
- excessive waterlogging and, as a result, rotting of cucumber roots;
- violation of temperature and humidity balance.
Lack of microelements
Just yesterday the green leaf plate of the cucumber was bright and juicy, but today the vegetable grower can observe that the leaves have become paler over the entire surface or in the veins
It is also important to pay attention to exactly how the yellowing spreads relative to the height of the plant.
Micronutrient deficiency is a relative concept. The soils are very rich in minerals. Their reserves will last for thousands of years. But their deficiency for the plant is associated with the inability of the cells of the root system to assimilate this or that element.
Global soil mineralization and a lack of organic fertilizers introduce an imbalance in the soil structure, and the plant responds to this by yellowing of the foliage.
Signs of a specific element being deficient
The plant whip quickly reacts to the lack of one or another nutrient. The leaf is an index. Upon careful examination, you can detect the following signs of starvation:
Bor
Young foliage will be the first to indicate a deficiency. The apical leaves of the cucumber will be chlorotic and pale yellow in color. In this case, flowering will be weak, and the resulting green plants will turn yellow and fall off.
Nitrogen
Nitrogen starvation is manifested by the blanching of the leaves of the entire cucumber vine. In addition, pallor will be characteristic of the entire cucumber plantation.
The deficiency begins to appear from the lower leaves. Dry spots gradually merge and the leaf falls off.
Potassium
If the absorption of this element is poor, it is not the leaves that turn pale, but their edges. Potassium is a mobile element, so the plant is able to transfer it from the periphery of the leaf blade to the center.
Copper
If cucumbers are sown on red soil, then copper deficiency is impossible. But sand, loam, and sandy loam cannot always provide a cucumber with copper.
Copper provides the plant with the processes of photosynthesis and respiration, and affects the vascular system of cucumber vines. Copper starvation cannot always be determined by foliage, but a small number of flowers and ovaries will tell the vegetable grower about the need for fertilizing.
Manganese
This element does not manifest itself by yellowing of the foliage. If there is a deficiency, the veins of the cucumber leaf become dark burgundy in color.
Calcium
With a deficiency of this element, pale stripes are located along the leaf and form a clearly visible stripe.
Zinc
Soils rich in humus completely provide the cucumber with zinc. The availability of the element in acidic soils is higher than in alkaline soils.
Cucumber is not very sensitive to zinc deficiency. In addition, if the level of nitrogen in the soil is optimal, then zinc starvation is impossible.
Iron
Lack of this element occurs extremely rarely and is accompanied by blanching of the apical leaves.
Soil care
Light cucumber leaves should alert you
Initially you should pay attention to:
- air permeability of soils, loosening and weeding;
- water balance. When the soil dries out, the absorption of minerals stops; the cucumber needs daily watering;
- pre-sowing activities. By enriching the soil with humus and ash before digging, you can significantly improve the soil structure and productivity.
It is very difficult to visually determine the excess of one or another element. By conducting a chemical analysis, we can clarify the problem.
It is generally accepted that cucumber, like other plants, selectively absorbs minerals necessary for vegetation and fruiting. An excess of these elements is extremely rare.
What are calcium nitrate fertilizers?
Calcium nitrate is a water-soluble chemical that provides plants with extra calcium and nitrogen. These elements are the building blocks for plants, making them strong and disease-resistant.
Calcium nitrate does not occur naturally - it is made by mixing inorganic calcium and nitrogen, namely limestone and nitric acid, followed by the addition of ammonia.
Calcium nitrate fertilizers are most often used by farmers to increase crop yields.
However, this does not mean that the home gardener cannot or should not use calcium nitrate on their fruits, vegetables and houseplants.
conclusions
To grow marketable cucumbers, you need to provide the plants with the full range of nutrients, especially the most basic ones - nitrogen, potassium and phosphorus. Fertilizers for cucumbers must be applied regularly - in autumn and spring, so that the plants do not have to be urgently raised after insufficient attention from the gardener.
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