Pale leaves in cucumbers: what to do, how to feed

In the process of caring for cucumber seedlings, gardeners may notice that in some plants the tops lose their rich green color, and the vine itself becomes lethargic over time. Why do cucumber leaves turn pale, and what can this effect be connected with - the quality of soil fertilizers, the frequency of watering, or an unsuccessfully chosen seed variety?

Why do cucumber leaves turn pale

The main cause of pale foliage in cucumbers is called a lack or, on the contrary, an excess of certain micro and macro elements. In most cases, a violation of the balance of nutrients entails a deterioration in the growth and presentation of cucumbers, but after taking appropriate measures, the fruiting of damaged bushes is fully restored.

The blanching of cucumber leaves occurs when there is a shortage of the following elements:

Nitrogen. The deficiency of this substance is reflected in the development of seedlings and the modification of all elements of the tops - the weak formation of lateral lashes and leaves, the fall of inflorescences without the formation of green ovaries, but the most indicative moment is the spread of yellowness on mature leaves of seedlings. If nitrogen fertilization is not made in a timely manner, the upper leaves begin to turn yellow, and last of all those that are above the first two shoots. It is possible to differentiate the lack of nitrogen in cucumber seedlings according to a peculiar scheme of covering the leaf with pale yellowness - the veins remain green until the last moment and lose color before falling off.
Decrease in the activity of photosynthesis with a lack of iron is immediately detected in the form of a loss of green color in young plants. Further inactivity results in the appearance of a dry edge along the perimeter of the damaged leaves, and the “washout” of the intense green color passes to mature leaves.The yield of cucumbers does not suffer from iron deficiency.

Calcium. Already formed leaves almost do not react to a lack of calcium, but young released leaves turn out to be very small and have an unnaturally dark shade of green. After a short time, new leaves begin to lose color around the edges and from the center. The pallor spreads in stripes across the surface of the leaf without affecting the veins, then these areas die off, and the damaged edges are bent down.
Light green, and then almost colorless tops of the leaves, with parallel wilting of the whole plant, indicate a lack of copper.
The fact that the leaves on the plant first began to turn yellow, and then acquire a brownish tint and shrink, will indicate a potassium deficiency. The presence of a large amount of peat in the soil composition will aggravate the progression of leaf damage with a lack of potassium.

Phosphorus starvation stops the growth of the cucumber bush - the vine stops reaching up, and the leaves on it become small and hard, as if leathery. Soon, the modified leaves become covered with pale green spots, similar to water stains, and fall off.

With excessive use of boron-containing dressings, the gardener runs the risk of causing plantings to irreversible changes and the death of the entire crop. along the edges. Soon, the yellowness spreads to the center in the form of spots that begin to dry out and wrinkle the leaf. Feeding the plant with any type of fertilizer should be temporarily stopped.

Why cucumber seedlings lose their green color - other reasons

What to do if the pallor of the leaves of cucumbers is noted during the period of active growth and development of the bush? First determine the cause, and then act in such a way as not to reduce the fruiting of plants:

Too early planting cucumbers in open ground. If you transfer cucumbers to a permanent place of cultivation, when the warming of the soil has not reached the desired temperatures, the leaves on the seedlings can not only brighten, but also fall off. The only way to fix the problem is to make a mobile tunnel greenhouse on arched racks right above the bed until the earth warms up enough.
Excessive amount of organics in the fertilizer. Feeding materials such as chicken manure should be temporarily abandoned. How to feed cucumbers in this case? It is best to use neutral mineral fertilizers - ash or grain solutions.

Lack of moisture in the soil or cold watering. The reason for the blanching of plants may lie in the irregularity of watering or freezing of the roots under the influence of cold tap water. You can correct the situation by setting an accurate irrigation schedule and using insulated and settled water for these purposes.
Excessive number of ovaries on the lashes. Green fruit formations draw vitality from the plant, causing the seedlings to become lethargic and the entire plant to lose color intensity. The number of fruit units should be reduced, distributing them evenly over the lashes, as they decrease towards the top.

Pinching the ovaries is a very important moment in the formation of a fruit bush. On average, it is believed that one plant should not have more than 23 ovaries at the same time, otherwise it will not cope with the load and begin to turn pale.

Causes of pale leaves - seedling diseases

Seedling diseases leading to the loss of color of the green part of the plant are more likely to occur in cucumbers in a greenhouse, since fungal and viral infections spread faster in a stuffy and humid atmosphere. Caring for plants in a greenhouse is also complicated by the fact that it is necessary to monitor the constant flow of fresh air.

The five most common diseases of cucumber seedlings, due to which plant leaves turn pale, are distinguished:

Mosaic disease. With this disease, which affects cucumbers both in the greenhouse and in the open field, the leaves of cucumber seedlings are covered with a spotty pattern of yellowish or pale color. Then the leaves of the cucumbers are tucked around the edges and shrivel. The disease spreads when infected seed material is planted or when diseased plants come into contact with he althy ones. The damaged part cannot be repaired. If the disease coverage area is not large enough, the damaged areas are removed, and the entire plant is irrigated with 1% fat milk.Heavily affected cucumber seedlings should be removed and the soil disinfected.

Powdery mildew is a whitish, lime-like deposit that covers green cucumber leaves, mostly outdoors. The disease is activated in wet weather with strong wind, watering or rain, and it spreads not only to the leaves of the plant, but also to the stem of the vine and even to nearby crops. If the leaves of cucumbers are characteristically pale in greenhouse conditions, then excess moisture or poor soil treatment before planting is to blame. Plants are cured with a composition of mullein and urea, taken in a ratio of 1: 50.

Peronosporosis. The principle of coating the leaf with plaque during peronosporosis resembles the signs of powdery mildew, only the color of the plaque is not white, but yellowish on the upper leaf plate and grayish on the bottom.When the gardener is inactive, the spots characteristically darken, and the sheet is deformed and dries. Causes of the disease: firstly, excessive watering, and secondly, unstable air or irrigation water temperatures. The fight against the fungus includes: limiting soil moisture up to the complete cessation of watering, removing damaged leaves and spraying the whole cucumber with an Oxych solution (two tablets per bucket of water).

Root rot. The fungus spreads to the plant from the roots, and first covers the lower tier of leaves with pale yellowness, and then moves to the next ones. Following the defeat of the leaves, the entire whip begins to die off, and the plant dies - rots on the vine. The causes of the disease are called immoderate watering, thick planting, in which the spores of the fungus pass from a sick cucumber to a he althy one, as well as high humidity and stuffiness in the greenhouse. Pale leaves should be removed immediately, and diseased plants should be sprayed with Infinito 61 SC solution.

White rot is another reason why cucumber leaves turn pale. You can find the fungus under the lower lashes of cucumbers, closer to the roots - jelly-like weeping spots appear there, which later become covered with white fluff. White rot quickly spreads along the vine, affecting the stem and most of the leaves. Green ovaries can also become white, especially those hanging on the lower lashes. The fight against rot begins with the removal of damaged areas of the plant that have turned white, and, with a small area of \u200b\u200bthe affected area, sprinkling the cucumber bush with a dry mixture of chalk and lime. Completely diseased plants will have to be removed.

With close plantings, characteristic of greenhouse cultivation, not only diseased plants, but also all those in the immediate vicinity are inspected and treated with solutions.

In the case when the disease is transmitted through the soil, that is, all types of fungal infections, special attention is paid to the disinfection of the soil at the site of the removed bush.