Why do cucumber leaves turn yellow?

Cucumbers are one of the main vegetable crops in the garden. People have been growing juicy and crispy greens for hundreds of years, and this vegetable continues to be the most popular. Currently, breeders have developed high-yielding varieties for vegetable gardens, greenhouses, and even for cultivation on the windowsill. However, vegetable growers, especially beginners, when faced with problems when growing this vegetable, cannot understand why the leaves of cucumbers turn yellow, dry out, and wither.

This undesirable phenomenon in garden beds occurs due to a violation of crop cultivation technology and for a number of other reasons. This article discusses the causes of yellowing and suggests solutions to the problems.

Causes of yellowness on cucumbers

Growing cucumbers is not difficult, but in the absence of minimal knowledge and skills, it is easy to lose a significant share of the harvest. To prevent this from happening, let's look at the main reasons for the yellowing of cucumbers.

Irrigation regime violation . When cucumbers are irrigated infrequently at a low rate, dehydration occurs in plant tissues. The first symptom of dehydration of cucumbers is that the leaves begin to turn yellow, what should you do? On days of drought and heat, it is worth increasing watering. When solving this issue, it is important not to overdo it, since excess moisture will cause the processes of rotting of the cucumber tissues to begin.

Attention! Proper watering should soak the top layer of soil in the garden bed by 10 cm.

Lack of nutrition in the soil . In open ground, cucumber leaves often turn yellow due to a deficiency of nutrients in the soil layer. This reason can be eliminated if you fertilize the cucumber beds during the growing season with complex mineral fertilizers. Yellowing is often caused by a lack of nitrogen in the soil.
Exposure to low temperatures . Overcooled cucumber plants experience severe stress; as a result, the leaves and ovaries of cucumbers may turn yellow.
Sunburn . Some gardeners water cucumbers by sprinkling on a hot sunny day. As a result, the leaves may become covered with yellow spots, which indicate that the plant has received sunburn. Shifting the watering time to early morning or evening helps solve the problem.
Fungal and viral diseases. Leaves often turn yellow due to cucumber diseases. Usually diseases are fungal or viral in nature. To save the harvest, you need to know what to spray cucumbers with and how to treat them. Fungal diseases, such as fusarium, can be cured by treating cucumber bushes with a fungicidal preparation. Viral diseases cannot be treated; affected bushes must be removed from the garden.

You may also like the article - “Diseases of cucumbers - names and photos.”

Injuries to cucumber roots are another reason why cucumber leaves turn yellow in the greenhouse and on the beds in the garden. The roots can be eaten by soil pests, they could also be damaged at the time of planting seedlings, during the process of care work.
Pest attack is the reason why the leaves of cucumber bushes turn yellow and curl. Attacks by aphids, whiteflies, mites, and thrips may cause the top, young leaves to turn yellow.
Plant aging. At the end of the growing season, the lower leaves of the cucumber bushes turn yellow and dry. This is a natural course of events that does not require intervention.

Reasons why leaves turn yellow around the edges

This is perhaps the most common problem when growing cucumbers. You should not be dismissive of such signals from the plant. If cucumbers have yellowness along the edge of the leaf, their fruiting is significantly reduced in time. There are 6 main factors that lead to this problem.

Temperature changes

Cucumbers are a heat-loving crop. In addition, with sudden changes in temperature, their leaves turn yellow at the edges. This leads to growth retardations and deterioration of fruiting qualities.

When growing cucumbers in a greenhouse, it is necessary to carefully control the temperature. If it is too hot, then good conditions will arise for the growth of bacteria, and the roots of the plant may rot.

Unsuitable growing area

The appearance of a yellow border on the leaves of cucumbers may be a consequence of an incorrectly chosen place for growing. Particular attention should be paid to the illumination of the plant. Cucumbers are a light-loving crop. But if exposed to too much sun, the leaves turn yellow and the soil quickly loses moisture. In this case, creating a shaded area above the planting will help. In the hottest sunshine, it is better to cover the plant.

Planting crops in the shade is not a good idea. The soil under the plant will be constantly moistened, and the leaves will not receive the required dose of ultraviolet radiation. Therefore, the best planting option is partial shade.

Lack of nutritional components

The surest sign that a plant lacks microelements is the spread of yellowness from the edge of the leaf throughout its entire plate. To solve this problem, you will need knowledge about what nutritional components the plant needs:

First of all, cucumbers need potassium fertilizers. They help increase the plant’s immunity to diseases and pests, as well as improve the taste of the fruit. A lack of potassium fertilizers is manifested by a yellow-green border on the leaves, a bitter taste of the fruit, as well as long shoots with a small number of ovaries. Potassium magnesium or ordinary ash will help the plant recover.
Boron deficiency can also be manifested by yellowing of plant leaves. Usually an accompanying symptom is the curvature of the fruits. You can feed cucumbers with boric acid during the flowering period. Dilute it in a ratio of 1 g per 5 liters of water.
The edges of cucumber leaves also turn yellow due to a lack of calcium. Moreover, in the absence of feeding, they can become brown and lethargic. In this case, chalk, dolomite flour, as well as any other fertilizer containing calcium will help.
When growing cucumbers on sandy soils, additional manganese is required. A lack of microelement appears as bumps on the leaf blades and their gradual yellowing from the edge to the center.
A weak-looking plant with no ovaries indicates a lack of nitrogen. In this case, the cucumber leaves turn yellow and dry out. The situation can be corrected using ammonium nitrate. But it is better to fertilize before the fruits set, since nitrogen accumulates in them.
Iron deficiency is indicated by yellow edges on the upper leaves. Iron sulfate will cope with the problem perfectly.

On a note! Iron sulfate is also an excellent preventive measure against fungal diseases.

Watering

In dry and sunny weather, it is recommended to water the plant abundantly daily. In moderate weather conditions, it is enough to do this 2-3 times a week.

If you do not provide the crop with enough moisture, the roots will begin to look for it on the surface and dry out in the sun. This in turn will lead to yellowing of the leaf blade and ovaries. Excess water also has a negative effect on cucumbers. Rot forms in the root system. Later it spreads to the stems, and the leaves become light.

Diseases that cause yellowing

Fungal diseases often affect the plant. The leaves begin to turn yellow when cucumbers are infected with one of the diseases:

Powdery mildew. It appears as a white coating and yellowing of the edges of the leaf blade. At the first sign of powdery mildew, the plant should be treated, otherwise all the leaves will fall off. As ready-made preparations, we can recommend “Bordeaux mixture” and “Topaz”. Organic lovers can use mullein. Most often, watering with cold water and sudden temperature changes lead to the appearance of fungus.
Fusarium. It begins with yellowing of the edge of the leaf. Gradually the disease spreads to the entire plant. Fungal spores block the supply of nutrients. This fungus cannot be removed simply by spraying cucumbers. The infected bush should be removed from the area and burned.
Root rot. Leads to rotting of the plant's root system. The leaves gradually turn yellow, starting from the very edge. The diseased bush is removed from the soil, and ash or chalk is added to the place where it is grown for prevention.

On a note!

It is better to remove a plant infected with a fungus from the site as quickly as possible to avoid the loss of the entire crop.

Pests

If a yellow border appears on the leaf blades of cucumbers, you should carefully inspect them for pest damage. Most often, the crop is attacked by cotton aphids, spider mites and greenhouse whiteflies.

Pest control can be quite difficult, and not everyone can recognize their appearance. Therefore, to restore the bush, I most often use universal insecticides.

Causes of yellowing and curling of leaf plates

The leaves of cucumber bushes turn yellow and curl in the following cases:

Lack of nutrients. The leaves first turn pale, then curl down, becoming like a parachute. Look at them carefully. If they have not changed in area, but have stretched out lengthwise, then most likely this was due to a lack of nitrogen. How to process cucumbers in this situation? Of course, fertilizer containing nitrogen.
Powdery mildew. This insidious disease affects cucumber bushes at the zenith of summer. As a result of the disease, cucumber leaf plates in the greenhouse and open ground turn yellow and curl. What should I spray on the bushes to make the disease go away? This disease should be treated with a solution based on Bordeaux mixture. If the seedlings begin to turn yellow in the greenhouse, you need to organize daily ventilation.
Impact of pests. When the leaves curl inward and turn yellow, this is a clear sign of a pest attack. It is necessary to inspect the underside of the sheet plates. They may be infested with aphids or spider mites. How to water cucumbers in such a situation? Insecticides are used against aphids; acaricidal preparations give excellent results in the fight against mites.
Viral diseases. If all agricultural technology requirements are strictly observed, the leaves may also turn yellow. It is important to know why the leaves of cucumber seedlings turn yellow. Perhaps this is a consequence of a viral disease. There is no need to think about how to cure a plant from this disease. Drugs against viruses have not yet been created. Sick plants should be removed from the garden.
Burns and hypothermia . Cucumber seedlings and adult plants may turn yellow due to non-compliance with the thermal regime. When leaves come into contact with cold or heated greenhouse glass, they can also turn yellow and curl.
Low air humidity . When there is insufficient air humidity, the plant curls its leaves to reduce the area of moisture evaporation. What is missing in order to solve the problem? It is necessary to water the cucumbers more often using the sprinkling method.

Cause of yellowing leaves in cucumbers No. 4: lack of nutrients

If the edges of cucumber leaves turn yellow, a yellow border appears (marginal burn), and the leaf plates themselves are wrinkled and deformed - this means that the cucumbers do not have enough potassium (the pear-shaped shape of the fruit indicates the same thing).
If at the same time the flowers set weakly or the ovaries dry out , the shoots are brittle and grow poorly - the cucumbers do not have enough boron.
Young leaves of cucumbers turn yellow, but the veins remain dark green (interveinal chlorosis) - cucumbers lack manganese or iron.
On old leaves, yellow-green spots (mosaic) appear between the green veins - cucumbers lack magnesium.
The leaves (including the veins) evenly turn pale (from light green to yellowish-green), become smaller and thinner - lack of nitrogen.

What to do: spray the cucumbers leaf by leaf with fertilizers containing the missing nutrient, or with appropriate mineral solutions. Organic fertilizers also help. For example, if there is a lack of potassium, cucumbers can be saved by an infusion of ash - 1 glass per 10 liters of water - spraying or watering at the root or a weak pink solution of potassium permanganate (spraying).

signs of magnesium and potassium deficiency in cucumbers

Why do the lower leaves turn yellow?

Some agricultural practices cause stress in cucumbers. As a result of these stressful phenomena, the lower leaves turn yellow and then dry out. This happens because the plant, faced with such a problem, directs all its forces to more promising upper tiers.
The leaf blades on the lower tier may turn yellow as a result of the natural aging of the bush.
Lack of light. The cucumber bush has many leaves, they shade each other, the rays of the sun cannot reach the lower tier. As a result, the lower leaves turn yellow.
When the bushes are overcooled and watering is irregular, the leaves below also turn yellow.
Insufficient content of nutrients in the soil, namely potassium, magnesium and phosphorus, also causes yellowness of the leaf blades of the lower part of the bush. Here you also need to know what to feed the cucumbers so that they do not turn yellow. A complete mineral fertilizer is suitable for this purpose.
Fungi contribute to the yellowing process of leaves located in close proximity to the soil level. Diseases - downy mildew, fusarium - first affect the lower leaf blades, then the infection spreads upward. Affected leaves must be removed and burned to prevent the spread of the disease.

What can you do if a yellow border appears?

At the first yellow spots on the edges of the leaves, you need to act immediately to prevent the death of the crop.

In the open ground

When engaged in the improvement of cucumbers in an open area, they take into account which factor caused the appearance of a light border on the leaves:

if the problem is a lack of nutrients, use complex fertilizers and growth stimulants;
in case of excess or lack of moisture, the watering regime is restored to normal;
when a fungal infection occurs, fungicides are used and the substrate moisture is normalized;
When insects attack, insecticides are used.

See also How to get a good harvest in a greenhouse and open ground

In the greenhouse

In greenhouse conditions, they struggle with other reasons for the appearance of a yellow rim on cucumber leaves:

normalize the irrigation regime, use warm, settled water;
if there is a lack of minerals in the soil, a mineral complex is added;
in case of insufficient pollination, a weak boron solution is used;
Infectious diseases are treated with chemicals and folk remedies by spraying and watering the soil.

At home

Cucumber seedlings grown on a windowsill are delicate and extremely susceptible to negative factors. Most often, the yellow edging of the leaves is a consequence of a violation of the watering regime. To normalize the level of soil moisture, cucumbers are not watered for several days, but only sprayed.

Why does the ovary dry out?

Yellowing of the lower leaf blades is not so bad. If the ovary and upper leaves turn yellow, it’s time to sound the alarm.

The main reasons for yellowing of the ovary are as follows:

insufficient sunlight on the upper tier of the plant;
exposure of bushes to low temperatures;
lack of nitrogen and potassium in the soil.

Attention! It is very important for cucumbers to maintain temperature conditions.

Table. Optimal temperatures for growing cucumbers

Growing period		Temperature, degrees C
before fruiting	during the day	21-24
before fruiting	at night	18
after entering fruiting	during the day	23-27
after entering fruiting	at night	19

Reason for yellowing leaves of cucumbers No. 8: cucumbers are poorly pollinated

What to do: When growing bee-pollinated varieties, provide good conditions for bees and bumblebees. In warm weather, keep the greenhouse open or ventilate it periodically. To attract pollinators, plant honey plants and dill near the cucumbers. Spraying with honey or sugar solution (half a tablespoon of sugar or honey per liter of water) also helps. Among the preparations are boric acid (5 grams per 10 liters), boron-magnesium fertilizers, Bud, Ovary.

Yellowing of leaf edges

Sometimes not the entire leaf area is covered with yellowness, but only the edges. What causes this deviation and what to do if the leaves turn yellow at the edges.

The reasons are as follows:

The cucumber bush is infected with a fungus . Powdery mildew begins to affect the leaves from the edges. At the slightest suspicion of a fungal infection, you need to spray the bushes with Bordeaux mixture.
Moisture deficiency in the soil. Rare watering leads to yellowing and drying of the leaves. Yellowness first appears from the edges.
Potassium deficiency . Due to the lack of this element, the edges of the leaf plates acquire a yellow border. The situation can be improved by adding potassium fertilizer.

Diseases and pests of cucumber plants, control measures

The edges of the leaves may turn yellow if the plant is affected by one of the diseases: powdery mildew, downy mildew, root rot, fusarium.

Powdery mildew. Initially, there is a whitish coating over the entire leaf and yellowing of the edges, then the leaf turns completely yellow and falls off. The reasons may be either temperature changes or watering with cold water. Control measures: treatment with a copper-containing preparation, fungicides, a 20% solution of colloidal sulfur, a solution of soda (50 g) and laundry soap (50 g) per 10 liters of water.
Downy mildew (downy mildew). The appearance of this disease is signaled by small yellow spots on the leaf; if not treated in a timely manner, then after 5-7 days the spots will increase in size, turn white, and the leaves will begin to dry out. The reason is the introduction of fungus or watering with cold water. Control measures: stop watering and fertilizing the beds, treat with copper oxychloride or polycarbonate according to the instructions, you can treat with Ordan or Ridomil-gold.
Fusarium. Pathogens are fungal spores that stop the plant from accessing nutrients. At first, the leaves turn yellow at the edges, later completely. Unfortunately, fusarium is incurable; the entire plant is removed and burned. It is advisable to completely replace the soil for next year’s planting.
Root rot. First, the rhizome is affected, then it spreads to the entire plant. The leaf turns yellow along the edge, then the entire plate, and the plant dies. The infected plant must be destroyed, and chalk or ash must be added to the remaining healthy plants. Also, the edges of cucumber leaves may turn yellow if they are “chosen” by one of the pests: aphids, spider mites, whiteflies.

At the height of the season, it is not practical to combat pests individually. It is much more effective to use universal insecticides, insectoacaricides or acaro fungicides. The listed types of drugs destroy a large number of harmful insects. These include drugs such as: Aktara, Apollo, Actellik, Envidor, Bi-58, Confidor, Tanrek, Sulfur (ground and colloidal).

Tips from the pros to prevent yellowing leaves

Determining the cause of the appearance of a yellow border on cucumber leaves is quite difficult. But you can try. First, it is necessary to carefully inspect the cucumber vines for the possibility of damage by disease or insects.

After inspection, decide what the plant needs: reduce or increase watering, add additional fertilizing or not, if it is a greenhouse, then use doors, transoms and vents to adjust the temperature regime.

Are yellowing spots dangerous?

If the cucumber leaves are covered with yellow spots, this is a consequence of the bush being damaged by a fungal infection. Similar symptoms may indicate the following diseases:

Anthracnose . Brown-yellow rounded spots with blurry edges appear on cucumber leaves. Later, concave, elongated cankers appear on the stems.
FMR (peronosporosis) . As a result of the defeat of cucumber bushes by downy mildew, round yellow spots appear on the top of the leaves. And on the underside of the plate, fungal hyphae appear in the form of white thin threads.
Sunburn . Yellow spots on the upper side of the leaves may be caused by sunburn. This especially happens when irrigation is carried out by sprinkling during high solar activity.

Important! To eliminate the disease, in the first two cases, you should use fungicidal preparations; in the latter, you should postpone the watering time to the morning.

Cucumbers: yellow border around leaf edge due to disease

Powdery mildew infection

Cucumber leaves may begin to turn yellow due to infection with a fungal disease such as powdery mildew. It is quite simple to understand that a garden bed has been infected by a fungus. At the very beginning of the onset of the disease, a white coating, similar to small spots, begins to form on the cucumber leaves. The disease begins to affect plants from the lower leaves. After about 5 - 7 years, this disease can affect the entire bush. The edges of the leaf turn yellow, after which the leaf dries and falls off. If you don’t sound the alarm in time and take action, the plant will die without even starting to bear fruit. It is possible to defeat powdery mildew. To do this, I use preparations such as Topaz or Zaslon; they have been tested more than once in the fight against powdery mildew and have shown excellent results. But it is worth remembering that these products should be used before the first ovaries appear.

We treat fusarium

Also, the appearance of yellow and dry foliage on cucumbers can provoke a fungus such as fusarium. This disease clogs all the capillaries of the plant, and this greatly complicates the proper flow of nutritious juices from the stem into the foliage of the cucumber. The disease is very serious and dangerous, and even with immediate detection and treatment of a fungal outbreak, the beds may not be saved. If you notice that fusarium is taking over your garden bed, immediately eliminate the affected plants; this measure will prevent the fungus from spreading to all cucumber bushes and you will be able to save part of the harvest.

How to treat plants

When cucumber leaves turn yellow, you need to know what to feed or treat the bushes to stop this negative process. The main reasons for this phenomenon are listed above:

weather factors;
pest attack;
plant diseases;
reasons associated with improper nutrition of cucumbers.

For nutritional deficiency

When leaves turn yellow due to lack of nutrients, you can use the following recipes based on fertilizers and folk remedies.

Recipe based on mineral fertilizers

To prepare a nutrient solution, you can use a purchased complex fertilizer, for example, Kemira Combi or Fertik. You can also prepare your own fertilizing solution for application under the roots in the following composition:

superphosphate – 10 g;
ammonium nitrate – 13 g;
potassium sulfate – 17 g;
water – 10 l.

Herbal infusion

This folk remedy for feeding is safe and environmentally friendly. An infusion made from the comfrey plant is most suitable for feeding cucumbers. The recipe is prepared and used according to the following scheme:

chop 1 kg of fresh herbs;
fill the mass with 10 liters of water;
leave for 7 days;
dilute the resulting mother liquor with water in a ratio of 1:9;
Apply the working solution for leaf and root application.

Urea solution

If it is determined that the yellowing of the leaves is caused by a lack of nitrogen, a recipe made with urea should be used. Why dissolve 45 g of urea in 10 liters of water. The solution is suitable for application at the root and for foliar feeding.

Mullein infusion

Cattle manure has long been used by vegetable growers to increase the nitrogen content in the soil and improve its structure. It has been found that it stops the development of powdery mildew. To prepare the infusion, you need to pour 1 kg of cow dung with 3 liters of water. After 3 days of settling, the solution should be filtered and diluted with three parts of water. Then you can start feeding.

Ash infusion

The lack of potassium in the soil can be easily compensated for with an ash-based solution. To prepare the infusion, 30 tbsp. ash is poured into 10 liters of water and left to infuse for 46 hours. The resulting infusion is used to spray plants.

For illnesses

When the cause of yellowing cucumber leaves is various diseases, you can use the following recipes to cure the disease.

Baking soda solution

This recipe is especially good for preventive spraying of cucumber bushes against a number of fungal diseases. You need to dilute 1 tbsp. l. soda in a bucket of water and, after mixing, start spraying.

Potassium permanganate solution

For initial symptoms of yellowing of leaves, even when the disease is not specifically identified, spray the plants with a solution of potassium permanganate.

Important! Mix the solution thoroughly until the crystals of the drug are completely dissolved. Otherwise, after spraying, leaf burns will occur.

If blackleg is rampant on cucumber plants, water the soil under the bushes with a solution of potassium permanganate.

Green herb based product

Peronosporosis can be cured with ordinary brilliant green. Prepare the following solution, which can be used for spraying three times within a month:

urea – 50 g;
whey – 2 l;
brilliant green – 10 ml;
water – 10 l.

Recipe based on trichopolum

This antibiotic kills fungal spores and has shown high effectiveness against powdery mildew. To prepare the solution, dilute 2 tablets in 1 liter of water. The disease is controlled by spraying.

Bordeaux liquid

A 1% solution of this drug is an effective remedy against powdery mildew and other fungi.

From pests

Pests that cause yellowing leaves can be repelled or killed with the following recipes.

Garlic infusion

This recipe can fight many pests and diseases. It is prepared like this:

chop the garlic and fill a liter jar with it;
add 20 g of liquid soap;
fill the jar with water;
mix the ingredients and put the jar in a dark place for a week;
Before spraying, the solution is filtered and diluted with 3 tbsp. l. mother composition in 10 liters of water.

Onion peel infusion

Pour 5 liters of water into an aluminum pan, add 1 tbsp. l. onion peel. Boil the mixture for several minutes. After cooling, apply for root application at the rate of 1 liter per plant.

Nitroammofoska

This complete fertilizer can replenish the balance of potassium, phosphorus and nitrogen in the soil, and also displace aphids from cucumber plantations. To prepare the solution, just dissolve 3 tbsp. l. fertilizers in 10 liters of water.

How to process and feed cucumbers

If the plant is already damaged, both traditional medicine that has stood the test of time and a variety of chemicals can be used to treat it.

Drugs

First you need to find out the cause of yellowing. And only then apply the appropriate remedy for its intended purpose. List of the most common drugs to help cucumbers:

Fitosporin. Helps cope with underlying diseases. Spray the solution on the bushes during the flowering or growing season. The drug contains special phytobacteria and microelements. For 5 liters of boiled water take 15-20 g of powder. Before use, the mixture should steep for 30-40 minutes. Spray cucumbers once a week for a month.
Oksikhom. This is a universal remedy that allows you to get rid of most diseases of garden crops. 20-30 g of the drug are diluted in 10 liters of water. Cucumbers need to be sprayed twice a month.
Topaz. It can be used not only to treat the plant, but also to prevent the occurrence of diseases. Topaz comes in various forms, but powder is the easiest to use. 20 g of the drug are diluted in 10 liters of water. Spraying is carried out 2 times a month. If after 30 days the leaves still turn yellow, the treatment can be extended for another 1 month.
Quadris. It is used to get rid of diseases of garden crops, as well as to prevent their occurrence. Add 200 ml of the drug to 2.5 liters of water, mix thoroughly and add another 2-4 liters. The solution is suitable for use throughout the day.

On a note!

It is best to treat cucumbers with preparations in calm weather, so that splashes do not fall on neighboring crops. In addition, rain falling within 24 hours after spraying will easily wash the solution from the leaves and the effect of the treatment will not occur.

Folk remedies

Traditional methods are effective at the very beginning of the development of a cultural disease. If you manage to notice the manifestations of the disease at the initial stage, you can use one of the following methods:

Add 1 liter of whey and half a glass of sugar to 5 liters of water. This composition will help the ovaries form faster.
Boil 700 g of onion peels in a bucket of water, leave for 10-12 hours, and then dilute with water in a ratio of 1 to 4. This solution can drive pests away from the leaves.
At the early stage of pest detection, cucumber bushes are treated with a weak solution of magnesium permanganate.
Tobacco planted between the rows will help cope with whiteflies.
A soap solution will get rid of aphids. Half a piece of laundry soap and a glass of ash are diluted in a bucket of water.
You can also remove parasites manually. This is done with a sponge soaked in soapy water.

How to feed cucumbers

The surest way to avoid yellowing on cucumber leaves is to regularly use nitrogen fertilizers. To prepare the solution, 20-30 g of fertilizer are diluted in 5-7 liters of water. It is not worth increasing the dosage in hopes of a greater effect. A solution that is too concentrated can burn the plant.

On a note!

Immediately after feeding, the cucumbers should be watered with warm water.

Nitrogen fertilizers can be used not only at the root of the plant. The solution can also be sprayed from a spray bottle onto cucumber leaves and shoots.

Why do leaves turn yellow and curl?

Deformation of cucumber leaves, along with yellowing, may indicate one of the following options:

Excessively dry air. The plant defends itself by curling its leaves to reduce evaporation.
A disease may be suspected.
Perhaps the plant was attacked by aphids or spider mites.
When leaves curl and twist, and growth occurs unevenly, some stretch more strongly, others weaker, it’s worth thinking about feeding. Signs of nitrogen starvation have been noticed; the crop needs to be supplied with nitrogen fertilizers.
If the leaves of cucumbers dry in a greenhouse, the leaves may be burned by the greenhouse glass. It can become very hot from the sun and cool significantly at night from dew. Therefore, it is worth making sure that the cucumber lashes do not come into contact with the glass.

If everything has been checked, but the situation cannot be corrected, an unpleasant option is possible. This includes, for example, viral plant diseases. In this case, you will have to part with the already grown plants and destroy them.

Eliminating yellowness along the edges of leaves

In cucumbers grown in a greenhouse, the problem of yellowing occurs most often. Sometimes cucumber foliage begins to turn yellow at the edges due to lack of pollination. This problem can be solved by attracting bees to the greenhouse. If this is not possible, hand pollination is used or a low concentration of boric acid solution is sprayed onto the bushes.

Important

Watering greenhouse cucumbers is carried out as the soil dries out. For irrigation, only warm water is used. At the same time as watering, you can fertilize the plants by adding mineral complexes to the liquid.

When growing cucumbers in unprotected beds, the problem of the appearance of a light yellowish edge on the leaves arises for the following reasons:

Copper or potassium deficiency. In the first case, the deficiency is compensated by treating the plant with Bordeaux mixture. In the second, complex fertilizers are applied or plants are treated with growth stimulants.
Incorrect watering. Usually yellowness appears due to poor irrigation. You can solve the problem by watering the plants more abundantly and more often, but without flooding them.
Waterlogging of the soil in rainy weather. Often, excess moisture becomes a favorable environment for the development of fungal infections. Then special antifungal drugs are used for treatment.
Pest infestation is eliminated using insecticides. Initially, it is necessary to determine which insect attacked the plants. Then you need to choose a drug against it.

When growing vegetables on a windowsill at home, special attention is paid to the plant. It is inspected regularly to watch for pest infestations or signs of disease. Watering errors may also be the cause. If the soil is too wet, you need to stop irrigating for a few days and watch the bush. You can watch the video for more information on how to eliminate yellow leaves.

Why have the lower leaves of cucumbers turned yellow?

Most problems with yellowing cucumber leaves concern their lower parts. This is explained by the fact that under unfavorable conditions they focus on supplying nutrients to their upper parts, where the ovaries and the leaves that feed them are located.

Yellowing of the lower cucumber leaves can be caused by:

Lack of lighting in the root zone. Any cucumber plants below are covered with large leaf blades that prevent the sun's rays from penetrating to them. In this case, the yellowing of the leaves growing at the bottom of the stem is a natural process: the plants themselves get rid of those vegetative organs that they no longer need. All that remains is to cut them off.
Chemical burns - yellow dry spots - form on the leaves after foliar feeding if the concentration of the drug has been exceeded.
Hypothermia of cucumbers. When the temperature drops, it is the lower leaves that begin to turn yellow first.
Lack of nutrients, most often phosphorus, potassium and magnesium.
Illiterate watering is also the cause of this problem.
Fungal diseases, pythiosis, fusarium and others, primarily affect the lower leaves, and then spread to the rest.
Sunburn occurs on the leaves. These are yellow spots that can form on leaf blades due to improper watering: if it is carried out during the hottest part of the day or if drops of water fall on the leaves and stems of cucumbers.
Natural aging: in this case, a change in color of the lower leaf blades is observed closer to the end of the season.

What exact measures need to be taken if the lower leaves of cucumber plants turn yellow depends on what exactly caused this phenomenon.

What to do if cucumber leaves turn yellow in spots

The formation of yellow spots on cucumber leaves may be due to:

Excessive moisture content in the soil, low oxygen content in it. This leads to disruption of the normal transformation of nutrients in the soil and disruption of photosynthesis in plant cells.
Magnesium deficiency.
Burns that can appear on greenhouse cucumbers from droplets of condensation falling from above, and on those growing in beds - from droplets of water if they are watered during the day, in the heat.
Affected by anthracnose or peronosporosis.

Such problems can be solved by regulating watering, timely loosening, applying magnesium-containing fertilizers, and preventive treatment against diseases.

How to treat cucumbers so that the leaves do not turn yellow

If the cause of chlorosis is ascochyta blight or bacteriosis, then the following measures should be taken:

yellowed foliage and damaged parts of the plant are cut off and burned;
the remaining part is sprayed with a 1% solution of Bordeaux mixture.

This method of control is effective if the disease is not very advanced. New shoots quickly grow from the leaf axils.

If there is a lack of microelements, foliar feeding is carried out. The best time for spraying is in the evening, when the sun drops to the horizon.

if there is a lack of nitrogen, spray with urea, dissolving 25 g per 5 liters of water;
if there is not enough magnesium, the leaves are irrigated with a solution of magnesium nitrate, 10 grams per 5 liters of water, or magnesium sulfate, per 5 liters of water - 50 grams of fertilizer;
If there is a lack of iron, the leaves are sprayed with iron sulfate; for this, 25 grams of fertilizer are added to 5 liters of water.

Foliar feeding is carried out two to three times, with an interval of 10 days.