Cucumbers turn yellow in the greenhouse - causes of the problem, methods of treatment

Our plans do not always match the circumstances. Problems can arise at any point in the season. In our case, the leaves turned yellow during the greenhouse cultivation. Why do cucumbers turn yellow and how to deal with this phenomenon?

Why cucumbers turn yellow - the causes of the problem

There are a huge number of sources of this problem. The main reasons were highlighted by experienced amateurs:

-Lack of sunlight;
-the bushes are very densely planted;
- violation of air humidity standards;
- lack or excess of nutrients;
- pollination is problematic;
- a large number of ovaries, take a lot of nutrition from leaves and stems;
- weather changes, sudden hypothermia, or overheating;
- damaged the roots when loosening;
- disease or pests.

Cucumber leaves turn massively yellow - treatment methods

There are many ways (methods) of treatment. It will take a very long time to consider everything, we will single out a few and analyze them in more detail.

1) Lack of light

In the case when the summer season is more cloudy, greenhouse plants receive a sufficient amount of sunlight, although they need it very much, most often that is why cucumbers turn yellow in rainy seasons. This problem can be solved by installing phytolamps in the greenhouse, the installation is carried out according to the attached instructions. All daylight hours, 12 hours minimum, the lamp works. After it is turned off, the plant needs rest. The plant must rest for at least six hours. It turns out the same daylight hours, with rest for the night, only artificially achieved.

2) Bushes are very densely planted

A very common case when a gardener, trying to get a very large harvest, plants bushes close, not observing the required distance. From here, the plants begin to press against each other, inhibiting development. They receive less light, nutrition, respectively, as well. According to the rules of agricultural technology, the number of seedlings per square meter is no more than 4 bushes. The planting features of each variety may differ, the planting scheme is usually indicated on a pack of seeds, when buying, consider this information, it is important.

3) Violation of air humidity standards

For comfortable growth of a cucumber, humidity should not fall below 85%. Failure to comply with the necessary conditions leads to increased absorption of moisture from the soil. Due to the lack of moisture in the ovary, the leaves turn yellow rapidly. Timely irrigation of the bust area, moisture evaporates and, accordingly, the necessary moisture balance is restored.
The irrigation process also has several points that it is advisable to adhere to:
-Do not use cold water, a sharp drop is detrimental;
- irrigation is carried out systematically, but not often. There should be no direct casting at the root: it is damaged, the root system begins to rot;
-mandatory, not long-term ventilation after irrigation;
- if after watering the moisture is kept in the upper layer, irrigation must be postponed;
- it is advisable to water it in the evening or early in the morning, but not during sundial, burns or just strong evaporation may occur, and such watering does not make sense.

4) Lack or excess of nutrients

Cucumbers turn yellow, growth rates decrease, green mass dries up? On the face of the inconsistency of the fertilizers applied to the soil, a few points to maintain the balance:
-the fruiting process requires a sufficient amount of additives containing nitrogen;
- when the plant is in full bloom, phosphorus is mandatory in the diet. Manure, especially fresh, is generally advisable to use only when preparing the soil in the fall. During the growing season, be careful with this fertilizer. In specialized stores, you can buy complex fertilizers and, if necessary, use them.

5) Pollination is problematic

Sometimes gardeners are faced with the problem of pollination. You can certainly buy self-pollinated varieties, but there are preferences that an experienced gardener does not change. Of course, they try to find hybrids for greenhouses that do not need pollination by bees, but if you still purchased a variety that needs pollinating insects, frequent ventilation will help you when pollinators have free access to plants, which promotes reproduction.

6) A large number of ovaries

The reason that cucumbers turn yellow can be a large number of ovaries, which take a lot of nutrition from the leaves and stems.
Greenhouse conditions are quite favorable for the growth of cucumbers, therefore, a very large mass of greenery is formed, the harvest of course suffers from this. The plant throws all the resources on the greens, and the remnants of strength and nutrition are given to the fruits. The bush must be formed in a timely manner.

The experience of many gardeners allows you to emphasize the nuances of the formation:
-first of all, remove the side shoots to the maximum;
-the very first ovaries are also removed, allowing the next to develop more thoroughly;
-Excessive leaves are a big problem. It not only interferes with the development of the bush, but also becomes the cause of the onset of diseases, the ovaries, of course, turn yellow in the first place.

Remove the first six nodules from the root, the formation begins from this moment. Then keep in shape throughout the season. Old leaves must be removed.
An overabundance of ovaries also leads to yellowing.

For those who are just starting to gain experience on their site, it seems that the more ovaries, the more abundant the harvest. Deceptive opinion. An abundant amount will lead the bush to a lack of nutrition and strength to form all the fruits obtained from each ovary. Development is poor, the majority begins to turn yellow, the yield is significantly reduced. In such cases, it is worth listening to the advice of experienced people who recommend leaving no more than 25 ovaries on one bush. This is the average of the expected yield results. If you observe the summer is hot, drought, you can increase the number of removed ovaries.

7) Changes in weather, sudden hypothermia, or overheating

The optimum temperature for cucumber seedlings is 18-35 degrees. A sharp decrease to +15 has a detrimental effect on the development of the plant, its formation, there is a slowdown in growth, yellowing of leaves and ovaries, and subsequently falling off.
One of the folk remedies will come to the rescue:

In the greenhouse, install a large water container, preferably with black walls, for example a barrel. All day the water will heat up, at night the heat accumulated during the daylight hours is released, the temperature rises, it becomes warm inside.

If there is a heat without periodic rains, there is a danger of drought, which threatens the seedlings, dehydration occurs. The ability to fertilize in cucumber pollen is lost. Control is needed, it should not be higher than +30 degrees. As a result of such an increase, a large amount of barren flowers, the tops turn yellow.

The solution to the problem is to ventilate the greenhouse more often, carefully. If it is hot in the greenhouse, but it is cold outside at that time, the drop threatens the seedlings, no less than overheating.

8) Damaged roots when loosening

Increased root growth, or the conditions for the development of the root system are very cramped (bushes are often planted), again lead to the fact that the cucumbers turn yellow. The system consumes too much, the upper part fails to form a bush, the plant does not develop.In the second case, the lack of nutrition occurs due to the weakness of the root system, there is not enough strength for the whole plant, the bush seems to freeze in development.

As a solution, initially follow the rules of agricultural technology when planting, do not plant close, when forming a bush, remove excess side shoots.

Diseases and pests

Having tracked all the situations discussed above, do you still observe that the cucumbers turn yellow? One reason remains - the problem lies in the appearance of diseases or pests that mercilessly began to destroy your crop by affecting the immunity of the cucumber.

These pests can be attributed to the most popular:

Melon aphid

The pest itself prefers open ground, but exceptions are everywhere and greenhouse varieties are also endangered. It feeds on aphids with plant sap, starting from the leaves, this situation leads to yellowing against the background of depletion of the system. If you do not find it in time and start a fight, the plant will inevitably die, and the parasite will move to neighboring, healthier bushes.

Spider mite

The sap of the plant is also the main food of this pest, it actively behaves in a greenhouse and a polycarbonate greenhouse. We noticed the fading of the bush in development, growth, the leaves fade, forming white specks, turn yellow, a cobweb has formed on the stems, these signs one hundred percent indicate the appearance of a tick.

Fusarium wilting

Outside, the weather is steadily hot, up to +35 degrees, it is high time for the development of the disease. Damage to the root system of the cucumber begins. After gradual damage to the leaves. The most dangerous period is the initial stage. It is very difficult to distinguish the disease, the symptoms of the onset of infection are not bright, almost imperceptible. First, the leaves are affected, in small areas, the size of a dot. Already at a later date, the infection spreads to the entire leaf.

Symptoms are similar to other medical conditions:
-mass yellowness of the sheet plate;
-the ovaries dry up;
-roots slowly begin the process of decay;
-color is practically not observed.

Powdery mildew

Refers to fungal diseases. High humidity and temperature conditions in a greenhouse or greenhouse serve as an excellent climate for development.

A white bloom appears on the leafy part, this is the main symptom of the disease. Plaque expands if not stopped, and the plant damaged by dew dies. In this case, the signs can be recognized already at the initial stage and treatment can be started urgently. To tighten is to lose the entire crop.

Downy mildew

Its activity begins already at the stage of planting seedlings. Without disinfecting the seeds, you risk getting infected seedlings at the beginning of growth. The second way dew appears is you diligently used fertilizing chemicals when growing seedlings and after transplanting them into the greenhouse. The period from the onset to the defeat of all seedlings in the disease is very short, almost a week.

It is not only possible, but also necessary to fight the disease. The first is folk advice or store chemicals. An important point is to properly feed.

Cucumbers turn yellow how to fight

Folk remedies recommend a reliable, effective remedy - onion peel infusion. Pour boiling water over, leave for 24 hours. Treat the leaves with infusion, pour all the remaining infusion under the root, carefully, do not form funnels that expose the root system.

Store chemistry must be selected with great care. Only if you know exactly the cause of the disease in your plants. By spraying, trying to choose the safest for humans, since the leaves are able to absorb the entire composition of the spray preparations, and then, passing through themselves, spread to the entire plant, including the fruits.

Top dressing can also be started with the safest means, for example urea, leaf dressing, spraying. Nitrogen is added to the soil, in a small amount.If you observe the yellowing of the root system, add phosphorus according to the instructions, do not overdo it.

Fertilizers containing potassium will help eliminate yellowing along the edge and tip of the leaves.

Prevention can be carried out (to prevent damage from a pest and diseases):
- regularly ventilate greenhouses and hotbeds;
- to carry out timely irrigation;
- be sure to control the temperature inside;
- to save the culture from being affected by fungal diseases, spray with 1% Bordeaux liquid.

The main thing in the business of a gardener, with experience and a beginner, is the correct approach and initial acquaintance with the rules of agricultural technology. Listen to the advice. All procedures should be carried out in due time, strictly according to the norm, and not according to the concept, the more, the better. Take care of your garden and he will respond in kind. Good harvests!