The edges of cucumber leaves turn yellow and dry : how to save the crop

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By the state of the leaves and fruits of the cucumber, you can understand what nutrients the plant lacks. If you notice that the edges of the leaves have turned yellow in cucumbers, then this indicates an unbalanced diet and, most often, a potassium deficiency. How can this problem be eliminated and prevented from occurring in the future?

Cucumbers have a relatively short growing season and quickly enter the fruiting phase. During fruit ripening, plants consume a large amount of nutrients, but especially a lot of potassium. This macroelement plays an important role in the formation of carbohydrates and cell division, increases the resistance of plants to diseases and adverse environmental conditions, and affects the taste of fruits.

It is with a lack of potassium that a pale yellow border first appears along the edges of the leaves, which becomes brighter over time. In acute potassium starvation, the fruits become pear-shaped, may be bitter, the leaves become covered with brown spots, and the border along the edges of the leaf plates becomes brown and begins to crumble, that is, the so-called. “marginal leaf burn”. First of all, the lower leaves suffer as older ones.

Cucumber leaves dry up and turn white, starting from the edge, also with a lack of calcium. However, this first appears on young leaves: they not only brighten, but also deform, then the growth point dies off, and the stems become woody. With calcium deficiency, the lower leaves remain green.

How to Prevent and Remedy Potassium Deficiency

Since cucumbers develop well and bear fruit only on fertile soil, when preparing the beds, apply not only organic fertilizers (biohumus, compost, humus), but also mineral fertilizers that contain the main macro- and microelements in an accessible form (Rodnichok, Biofertilizer Vegetables, OMU Universal, AVA Universal, etc.).

During the fruiting period, fertilize every two weeks with potash fertilizer: potassium sulfate (15 g per 10 l of water, 0.5 l under a bush), potassium monophosphate (10 g per 10 l of water, 0.5 l under a bush) or complex fertilizer with high content of phosphorus and potassium (Orange Crystal, AgroMaster 3.11.38+4, Agricola for cucumbers, zucchini, squash, etc.). If the soil in the area is acidic or slightly acidic (pH lower than 6.7), carry out 2-3 root dressings of cucumbers with ash infusion (150 g per 10 liters of water, 1 liter under a bush).

Root top dressing of cucumbers spend only after watering. Try to alternate root and foliar top dressing, mineral and organic. Adjust the amount of fertilizer applied depending on the condition of the plants and the recommendations of the manufacturer.

Frequent fertilizing with small doses of various potash fertilizers is better than a single application of potassium in large quantities, because with an excess content in the soil, potassium becomes inaccessible forms and prevents the absorption of magnesium, calcium, ammonium nitrogen, manganese and some other elements.

Why potassium is poorly absorbed

Even if, when planting plants, you applied the right amount of potash or complex fertilizers, this does not mean that the plants will definitely receive good nutrition. For example, potassium, like nitrogen, is a rather mobile element and can simply be washed out of the soil, especially if your site has sandy, sandy or peaty soil. But there are other reasons for poor absorption of potassium:

  • Low or very high temperature . The optimum temperature for the development of cucumbers is 20-25°C during the day and 16-18°C at night. However, it is not always possible to create such ideal conditions. At temperatures below 12 ° C, the cucumber root system loses its ability to absorb water and nutrition from the soil, therefore, on cold days, it is advisable to carry out only foliar top dressing. And in the heat, when the soil overheats, many batteries also become inaccessible. In this regard, fertilizers should be applied at an air temperature not higher than 25 ° C, for example, in the morning or evening.
  • Too much calcium in the soil . With excessive calcium application (for example, during soil deoxidation, liming), potassium binds and is not absorbed by the root system of plants, since potassium and calcium are antagonist elements.
  • Irregular watering . Cucumbers, as you know, are a moisture-loving culture. Therefore, plantings should be watered regularly, as the soil dries up, using warm water with a temperature of 23-25 ° C for this. In order for minerals from the soil to be well absorbed, the earth in the root zone should always be moderately moist, especially during the fruiting period. However, excessive watering of cucumbers should be avoided, as this leads to the washing out of the main nutrients and the appearance of root and root rot.
  •  How to water cucumbers for a good harvest
    Everything you need to know about watering cucumbers, depending on the season and growing conditions.

In order to protect the soil from temperature changes and retain moisture in the root layer, it is advisable to mulch the bed with hay, straw, rotted sawdust or other material. Mulching will help ease planting care and reduce the frequency of watering.

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