At unfavorable conditions, the first signs of illness or errors in care cucumber leaves begin to turn yellow. It can be said that appearance cucumber leaves are an indicator of the condition of the plants. Why do cucumbers turn yellow, how to determine the cause and correct the situation, read on .
The most common causes of yellowing leaves in cucumbers are unfavorable conditions, which arise due to weather conditions or improper care.
Due to lack of lighting, cucumbers, the leaves at the base of the stem turn yellow when the vines become lush, branched, the lower leaves do not have enough sunlight, so the old leaves die off. Yellowed lower leaves on the stems should be removed. To ensure that cucumbers lose as little foliage as possible due to lack of lighting, do not thicken the plantings, tie up the vines and form a vine.
A common cause of yellowing cucumbers is improper or insufficient watering.. In hot weather, cucumbers require a lot of moisture, since a lot of water goes into fruit formation and high temperature leaves evaporate moisture faster. On hot, sunny days, cucumbers need to be watered every day so that the soil under them is always moderately moist. If it is not possible to water daily, then mulch the surface of the earth, then the moisture will remain inside longer
It is important to water the cucumbers with warm water that has settled in the tank. Cold water leads to rotting of the root system and causes stress in plants.
The leaves of cucumbers begin to turn yellow en masse at the end of summer or early autumn, when the nights become cool or when cold weather sets in. Cucumber is a heat-loving plant and when the temperature drops to +10 degrees it stops growing, and at temperatures around zero degrees it dies. To protect cucumbers from changes in day and night temperatures, cover them with film, acrylic, spunbond or other material attached to arches.
Cucumber leaves turn yellow differently when there is a lack of any nutrient. By external signs you can determine what fertilizer needs to be used to restore plant strength and fruit growth.
If the cucumber leaves begin to turn yellow at the edges, they have a bright border with dried out tips, and the central part of the leaves is wrinkled or deformed, which means that the cucumbers do not have enough potassium. With potassium deficiency, cucumber fruits grow pear-shaped. In this case, use any potassium fertilizer without chlorine or wood ash to feed the cucumbers.
If young leaves of cucumbers turn yellow, and their veins remain green, which means the plants lack manganese or iron. Spray with potassium permanganate or iron chelate to quickly replenish the balance of plant nutrients.
If the old leaves of cucumbers turn yellow, a mosaic pattern or pale green and yellow spots appear on them, which means that the cucumbers do not have enough magnesium.
If cucumbers have light or yellowish veins, and the shoots are thin and small, which means that the plants need fertilizing with nitrogen fertilizer.
It is important to distinguish the signs of yellowing of cucumber leaves due to care conditions from signs of diseases or the appearance of pests in order to begin treatment of plants as early as possible and save the harvest.
Downy mildew or pecospora causes the appearance of numerous pale yellow spots on the leaves of cucumbers, which gradually increase in size, turn brown and dry out, and a white powdery coating can also be seen on the leaves. Downy mildew appears during sudden changes in temperature and humidity, most often in late summer and autumn, when it is hot during the day, cool at night and dew falls in the morning.
To treat downy mildew, the preparations “Hom”, “Oxyhom”, and Bordeaux mixture are used. During the fruiting period, it is better to turn to folk remedies; to combat downy mildew, use a soap solution of soda (30 grams of soda and 10 grams of soap are diluted per 5 liters) or a solution of iodine with milk (20-30 drops of iodine and 1 liter of milk). An infusion of ash (2 cups per 3 liters of water) and an infusion of onion peels are effective against diseases on cucumber leaves.
Powdery mildew on cucumber leaves can be determined by the appearance white plaque, the leaves on top seem to be powdered with flour. At the first signs of the disease, it is necessary to begin treatment and continue preventive spraying for a month every 7-10 days. To treat powdery mildew, the drugs “Topaz”, “Fundazol”, “Skor”, “Previkur”, “Vitaros” are used.. However chemicals It is forbidden to use cucumbers during the fruiting period, so gardeners turn to safe folk remedies. Spraying with a solution of soda or garlic infusion helps against powdery mildew.
If the leaves of cucumbers wither even after watering, then they turn yellow and dry out, then you should check the roots of the plants. When root rot appears, the root collar becomes brown, with dents, and the diseased plant is easily pulled out of the ground. To protect cucumbers from root rot, a number of preventive measures should be taken, starting from disinfecting the seeds and soil during sowing, and then maintaining the recommended distance between plants when planting and watering the cucumbers only warm water. Diseased plants with root rot should be watered with the preparation “Fitosporin”, “Baktofit”, “Fundazol”, “Strekar”. To restore the root system, use a root growth stimulator - “Kornevin”.
When pests appear on cucumbers, their leaves immediately begin to turn yellow., since insects mainly feed on sap from leaf blades. When spider mite, whiteflies, thrips, light yellow dots first appear on cucumber leaves, then the leaves completely turn yellow and dry out. Insecticides “Iskra”, “Intavir”, “Aktara” will help get rid of pests on cucumbers.. Spraying with the drug is carried out on the top and bottom of the leaves, since insects lay larvae on the underside. Carry out pest control in accordance with the safety instructions for using the drug.
Why do cucumber leaves turn yellow? What to do? Gardeners turn to search engines with such questions when the problem is already clearly visible. But wait until you start panicking. After all, everything is often fixable, and the cucumbers can still be saved.
The only difficulty is an accurate diagnosis of why the leaves turn yellow. Sometimes it can be difficult to determine the real cause. Well, you’ll have to use the method of elimination and turn your head on periodically. Then everything will definitely work out.
Below we will look at the most common options for changing pigmentation and tell you what to do in such a situation.
Improper watering
Since childhood, many people know that cucumbers love water. So they pour until they are stupefied and no matter how much you don’t mind. But such a basic procedure as watering must be carried out according to all the rules.
This plant is heat-loving. In the regions where cucumbers originate, cold rains are rare. Mostly warm water pours from the sky. This means that our cucumbers also need to be given warm water. Otherwise, some will lower the pump into the well and let’s pump ice streams into the beds. Try standing under such a shower yourself. I don't think I'll like it.
So the cucumbers turn off the small feeding roots so as not to catch a cold. And leaves and fruits require water. It turns out that even if they are in an icy slurry of soil and water, the plants dry out. The leaves will turn yellow quickly with this care.
Another situation. The water for irrigation is warm, but it is not enough. Instead of drinking quality water 3 times a week, the owners spray a little from a watering can every day. The top layer of soil is always wet. And at a depth of 8-12 cm, where the bulk of the roots are located, it is dry. It turns out the cucumbers were dried again.
Or the other extreme. Water the cucumbers with warm water, often and a lot. Well, it would seem, what else is needed? Air access to the roots is necessary. They cannot work constantly for wear and tear; they also need to be ventilated periodically. What if your “legs” float in a warm swamp?
All sorts of sores of the root system begin, insidious rots attack. The roots gradually die off. The leaves turn yellow, the owners think that the plants do not have enough water, and they pour even more. The problem is getting worse.
What to do? To begin with, water correctly. No one will tell you the exact amount of water per plant or frequency. And don’t listen to all these “25 liters of water per bush with each watering.” How can advisors know what the weather or climate is like in your area? They also don’t know what type of soil and under what conditions your cucumbers grow.
The best reference point is your garden bed. They came, pulled the tops apart, and looked. If it’s not clear, then you can pick up some earthen soil. Humid? Stop watering! Dry? So it's time to give the cucumbers a drink. That's all science is.
Sunburn
Continuing the topic of water, let's talk about a great misconception. Absolutely all sources strictly prohibit watering cucumbers in the heat from above. Allegedly, sprinkling provokes sunburn and massive yellowing of leaves.
Sorry, but the yellowing of the leaves is caused by your negligence and unwillingness to work with your brains. Look at your cucumbers at 14. What does it look like? That's right, on sagging rags. This sun evaporates the remaining moisture from them, and then dries them to the state of straw. Hence the burn.
What to do? Save! Help urgently cucumber plantings endure the solar mockery! Directly from above the leaves, sprinkling should be used to refresh the plantings. This reduces the temperature of the leaf, saturates it with liquid and increases the humidity of the air around it.
And don’t talk about drop lenses. If the blades are saturated with water and their temperature is reduced, then your scary lenses will need a lot of force to damage the surface of the sheet. By the way, after the rain the sun often shines too. How many plants blazing from lenses have you seen in your life?
Pests
These little enemies suck out all the nutritious juices from the leaves of cucumbers, gnaw at the root system, and eat the stems. As a result, the plant becomes weak, lack of nutrition appears, and the leaves turn yellow.
Additional feeding will not help. First you need to identify the insidious guests, then get rid of them, and only after all help the cucumbers recover.
What to do? Each type of pest requires its own method of control. No doubt, you can hit them heartily with a decent dose of insecticide. But how do you eat cucumbers later? After all, they mature quickly and will not have time to get rid of the poison.
There are 3 solutions, both are harmless to people and animals:
- Use all kinds of decoctions and infusions of strong-smelling natural ingredients. This onion peel, tansy, mint, valerian, marigold, garlic peel. You just need to periodically spray the affected cucumber leaves with diluted liquid. It is advisable to thoroughly wet it bottom side leaves. This is where the largest concentration of uninvited guests is observed.
- Traps. Possibly with poisonous bait. The pests will eat enough and happily throw back their paws, but the cucumbers will definitely not eat. If you don’t want to use poison, then you just collect insects in traps and give them to your neighbors or your chickens. Take it out of the area and destroy it. You bury it very deep into the ground. There are plenty of ways.
- New on the insecticide market. With bio prefix. Can be used to get rid of all types of harmful insects. It is a conglomerate of fungal spores and a predatory nematode. The little predator attacks pests and infects them with fungus. This, in turn, quickly grows throughout the internal organs of the insect and kills it. Everything takes from 4 hours to a day.
The only disadvantage of option 3 is strict adherence to the instructions. The conditions and storage time of the drug are clearly stated there, as well as the temperature range in which the bioinsecticide works most effectively.
Cold
The banal reason is temperature fluctuations during the day. For example, during the day it is scorching hot, but at night it is already freezing. This usually happens in August. Cucumber roots stop functioning normally in cooled soil. And the overgrown tops and filling fruits require nutrition in the usual dose. What remains for the plant? That's right, take a supply of nutrients from the leaves. Burdocks begin to turn yellow, then dry out and die.
Increased feeding will not bring the desired result. No matter how much nutrition is added to the soil, the cucumber is not able to absorb it.
What to do? Apply foliar fertilizing, preferably with nitrogen, and grow new roots. This is done very simply. First, almost all the lashes are buried to a length of up to 30 cm. The whole thing must be sprinkled with damp loose soil. It is recommended to water the digging area with a solution of a root formation stimulator for the first time. This will allow the cucumber to quickly grow new roots, which will help the bush absorb the proper amount of nutrition.
And the leaves will need to be fertilized 2 times, with an interval of 5-7 days. For this purpose, 10 l clean water take Matchbox regular urea (without top) or 2 tbsp. l. pharmaceutical solution of ammonia. Mix the resulting liquid thoroughly and spray the cucumber plantings heartily.
Lack of nutrition
By the way, about fertilizers. Their lack can also cause yellowing of cucumber leaves. Some gardeners are categorically against the use of chemicals on their personal plot. Of course, biological fluid green manure- a good thing. The cucumbers take it with a bang. But for normal growth and development, the menu must be complete.
Agree, it’s hard to constantly eat only nitrogen. Other microelements are also needed. For example, potassium, manganese, iron, boron, phosphorus, molybdenum, zinc. In small quantities, but still a cucumber cannot exist normally without them. And a person will not be able to provide natural nutrition required quantity nutrition. And on nitrogen alone from greens, the plants will be loose, watery and the fruits will grow tasteless. The leaves will be lush and green at first, but not for long. Then they quickly lose their attractiveness and turn yellow.
What to do? Feed. Let's go to the store. We choose any complex mineral fertilizer. Read carefully the content of microelements. We choose something that has less nitrogen and more other substances. We buy it and take it home. Once again, carefully read the instructions for use, especially the manufacturer’s recommendations. We strictly follow all requirements.
We deliberately do not provide dosage and frequency of use here. mineral fertilizers. Because each complex of microelements has its own, and it is impossible to guarantee anything remotely. But believe me, your cucumbers will respond to such care with gratitude, a large harvest and beautiful green leaves.
Diseases
This is the most common cause of yellowing cucumber leaves. None of the above species causes such harm as spores of pathogenic fungi and pathogenic bacteria. They lie in wait for your plants at every step and stage of development.
It all starts with the infected planting material and damaged soil. Then the insect pests carry various viruses on their legs. Cool, wet weather encourages fungal growth. In a greenhouse or greenhouse, bacteria from last year may remain on the supports and walls. It would take a long time to list all the dangers. A book is not enough to describe the method of combating each disease.
Before sowing seeds in the ground or for seedlings, they must be disinfected. Nothing better than a strong, hot solution of potassium permanganate has yet been invented. Planting soil is cleaned of bacteria by deep freezing or roasting in the oven.
In a greenhouse (greenhouse) you should change at least every year upper layer soil for a new one. If it is impossible to do this, you should definitely spill the soil with potassium permanganate or a solution of phytosporin. Arches, frames, supports, wall and ceiling materials must be treated with a fungicide solution or at least fumigated with a sulfur smoke bomb. The tobacco shop does a good job too.
The best protection against diseases and fungal rot is prevention:
- Strict adherence to crop rotation. Many people neglect this, but in vain. Bacteria tend to accumulate in soil. And constant, year after year, planting melons in one place is an indirect cause of yellowing of the leaves.
- Periodically inspect cucumbers for suspicious spots or streaks. Otherwise, most gardeners begin to beat the drums only when the cucumbers are signaled by the massive yellowness of the burdocks.
- Regular preventive spraying of bushes with any fungicide of biological origin. Modern industry offers a great variety of them. We won’t name it here to avoid advertising, but if you want, you can find both the name and instructions.
Biofungicides are absolutely harmless to people, animals and insects. You don't even need gloves to use them. And the benefits are invaluable.
If you still missed it and the disease has already begun its victorious march, then quickly get rid of the sick cucumber or put it in quarantine. It is quite possible that the remaining bushes have not yet become infected. But it's better not to take risks.
The affected plant must be pulled out by the roots, taken outside the site and burned. The soil underneath should be immediately disinfected. This measure will definitely allow you to sleep peacefully.
After reading our article, you will no longer worry about the question of why cucumber leaves turn yellow. What to do? - you know too. Take a closer look at your plants and good harvests to you.
Video: what to do to prevent cucumber leaves from turning yellow
Kira Stoletova
Cucumbers are considered a simple and easy crop to grow and care for. But, like any other plant in the garden, this vegetable requires attention. And especially when any negative changes are observed on the plants. Gardeners often encounter yellowing leaves. At such a moment, the question arises of how to treat cucumber leaves if they dry out and turn yellow. But, you should not rush into processing without finding out the reasons for the occurrence of such a problem.
Main causes of yellowing
Yellowing of the leaves of cucumbers indicates a violation of the growing season. And to solve the problem, you need to understand what exactly caused this violation.
Yellowing occurs for the following reasons:
- lack of lighting;
- sunburn;
- violation of the water regime;
- sudden changes in temperature, hypothermia;
- nutritional deficiencies;
- pest damage;
- infection with viral or fungal diseases.
Depending on the cause of its occurrence, yellowing will have its own characteristics. To determine them, it will be enough to carefully examine the bushes. Damage will vary:
- localization;
- shades;
- contours of yellowed areas;
- accompanying symptoms.
Based on the causes of yellowing, appropriate measures can be taken. In each individual case they will be different.
Lack of lighting
Lack of lighting can occur at different stages of development. Most often, this problem can be observed during the period of growing seedlings or already during fruiting.
If leaves turn yellow at the seedling stage, this most often occurs due to the location or cloudy spring days. If there is not enough light, they will become pale with a yellowish tint. This occurs due to slow photosynthesis processes and insufficient amounts of produced nutrients. This problem can be easily solved by simply moving the seedlings to a more illuminated place or illuminating them with a phytolamp. And for a short time The cucumbers will return to their original bright green color.
Sometimes the leaves of mature plants dry out; this is an inevitable process.
Having grown a large mass of greenery, the bushes begin to shade each other. Those at the bottom of the stem do not receive enough light. This is a natural process. In such a situation, you can remove the yellowed and dried leaves and slightly thin out the bushes, cutting off excess non-fruiting vines. Such measures can partially extend the growing season.
Sunburn
If small yellow spots with clear outlines appear on the bushes, and the day before watering was carried out in sunny and hot weather. The cause of this yellowing is a burn. Such yellowing will not harm the bushes, but it should be remembered that watering the plants should be done in the morning or afternoon. And it is strictly forbidden to water the bushes under the scorching sun.
Violation of water regime
Cucumbers, like all pumpkin plants, are moisture-loving plants. Common cause yellowing and drying out due to lack of moisture and drought. On bushes, the tips of the leaves dry first, and then the entire leaf.
Solving this problem will not be difficult. It is enough to regulate watering, carry it out regularly in sufficient quantities. It has a beneficial effect on the condition of bushes and spraying with water. But it is important to remember that overwatering, like drying out, can be harmful.
Sudden temperature changes, hypothermia
If the day before there was a dramatic drop in temperature, cold rains, or cold snaps at night, then the plants react very quickly to such stressful conditions. And the leaves of cucumbers may begin to turn yellow. This is due to the fact that when the temperature drops, crops are poorly absorbed nutrients, accordingly, the nutrition of the vegetative organs is disrupted. Stabilizing the temperature will normalize the condition of the cucumbers, and the leaves will stop turning yellow.
If, according to the forecast, the cold weather continues, it is worth covering the cucumbers with a non-woven fabric. White agrofibre is good; it is light, transmits light, and warms well. And they can cover even adult plants.
Nutrient deficiency
When there is a nutrient deficiency, treatment is absolutely necessary and must be done immediately.
Leaves can turn yellow either due to a deficiency of the entire complex of nutrients, or due to a lack of a specific microelement. Depending on what exactly the bushes lack, you need to decide how to treat the stems and leaves of the cucumbers.
Yellowing occurs when there is a deficiency:
- nitrogen;
- potassium;
- calcium;
- gland;
- magnesium
You can determine what exactly cucumbers lack by looking at the characteristics of yellowing, as well as taking into account the accompanying symptoms.
Nitrogen deficiency
Nitrogen plays important role in the process of growth. If there is a shortage of it, not only will the leaves turn yellow, but other symptoms will also appear:
- growth slows down;
- new shoots develop poorly;
- the ovary falls off.
In such a situation, the bushes need to be treated with nitrogen fertilizer; this can be either mineral or organic. Urea and chicken manure will do.
Urea is used in a solution for foliar treatment. To do this, dissolve 10 g of urea in 10 liters. The resulting solution is sprayed onto the plants. It will be enough to carry out two such feedings with an interval of 10 days.
If organic growing of vegetables is preferable, then fertilizing is well suited for replenishing nitrogen deficiency. chicken droppings. To do this, prepare a solution. To 10 liters of water, just add a glass of manure, mix well and leave to ferment for 2-3 days. The finished slurry is diluted with water. Add 250 ml of solution to a bucket of clean water. This fertilizer is applied to the bushes, making sure that the fertilizer does not get on the plant.
Potassium deficiency
With a deficiency of potassium, the leaves have a yellow border along the entire edge, and over time they turn brown. In parallel with this yellowing, the following is observed:
- lash pulling;
- absence of ovary.
A sufficient amount of potassium plays an important role, since it is this trace element that helps absorb other nutrients. And this deficiency will, after some time, lead to a deficiency of other nutrients, since even if they are present in the soil, they will not be absorbed. To replenish the supply of potassium, potassium magnesium or ash, which is very rich in this microelement, is used for processing cucumbers.
It is better to use potassium magnesium in the form of a solution, so it is quickly absorbed by plants. To do this, 20 g of fertilizer granules should be dissolved in a bucket of water. This solution can be watered at the roots of the plants or sprayed. Ash can be used both in dry form and in the form of an ash solution. When applied dry, add 2-3 tsp under one bush. the ash is buried in the ground and watered with clean water. You can also prepare a solution for watering. Dissolve a glass of ash in a bucket of water and water it at the root; 0.5 liters of solution will be enough for one plant.
Lack of calcium
In case of calcium deficiency, the leaves first turn white, then curl and fall off. Often a deficiency of this microelement occurs when plants are grown in acidic soils. Therefore, you should check the acidity and reduce it if necessary. If the pH is normal, then you need to treat the cucumbers with calcium sulfate, and also use eggshell fertilizer, which contains predominantly easily digestible calcium.
The eggshells are washed, dried and ground into powder. Powder is sprinkled on the bushes. 1 tsp is enough for one plant. such feeding.
Iron deficiency
With iron deficiency, so-called chlorosis occurs. With chlorosis, the leaves turn yellow, but the veins remain green. You can replenish the deficiency of this microelement using ready-made preparations:
- Iron chelate;
- Micro Fe;
- Antichlorosis;
- Ferylene.
The drug is dissolved according to the instructions and sprayed on cucumbers.
You can also treat cucumbers with homemade iron chelate. To do this, you will need 10 g of iron sulfate and 20 g of ascorbic acid; they are dissolved in 1 liter of water. The solution is sprayed and added to the plants.
Magnesium deficiency
With magnesium deficiency, the leaves change color from yellow to purple, the veins, as with chlorosis, are green for some time. In such a situation, cucumbers are treated with a solution of magnesium sulfate. For 10 liters of water, 20 g of fertilizer is enough. Treatment is carried out after the start of flowering. Spray the cucumbers thoroughly. Such treatments need to be done 2-3 with a frequency of 10 days.
Pest infestation
The main pests that affect:
- spider mite;
- whitefly;
- mealy worm.
If detected and treated in a timely manner, they will not be able to cause serious harm to cucumbers. For processing, you can use different, maximum effective means. Acaricides (Apollo, Aktelik, Oberon) can cope with spider mites and mealyworms. Broad-spectrum insecticides (Confidor, Envidor, Sunmite) will help combat aphids and whiteflies.
Infections with fungal or viral diseases
Among fungal diseases, one of the symptoms of which is yellowing of leaves and which can affect cucumbers, can be identified:
- fusarium;
- false powdery mildew;
- anthracnose
When infected with Fusarium, in addition to yellowing, the plants also wilt and then thin the stems. If a disease is detected, it is necessary to treat with Trichodermin or Fundazol. In case of infection, these drugs are used to water the soil around the plant and spray it.
If cucumbers are affected by downy mildew, then outside The leaf blade will have yellow spots without clear outlines, and a whitish coating underneath. Fungicides (Topsin, Acrobat, Metaxyl, etc.) will help cope with parosporosis. You can also use folk method. You need to prepare a solution with 25 g of soda, 5 g of soap and 5 l hot water, to stir thoroughly. The cooled solution is sprayed on the cucumbers, and the soil near the bushes is also spilled.
Another fungal disease in which the leaves turn yellow and dry out - this is anthracnose. With anthracnose, yellowish spots appear, and then turn brown, and become up to 5 cm in diameter, localized along the edges and between the veins. After some time, ruptures appear in the spots. In case of anthracnose, it is necessary to treat with fungicides (Quadris, Previkur, Polyram).
Conclusion
There are many causes of yellowing, and most are not difficult to deal with. But it will be much easier to prevent the occurrence of factors that can provoke this. By following correct agricultural practices, use safe preparations to prevent pests and diseases. As a result, healthy and green cucumbers will grow.
Yellowing of the leaves of cucumbers in most cases indicates a violation of agricultural cultivation techniques, and somewhat less often - that the plant is sick or lacks nutrients. Such a nuisance can occur at any stage of the growing season. So, let's figure out why yellowing occurs and how to deal with this scourge.
Why cucumber leaves turn yellow: main reasons
There are many reasons for yellowing leaves, but Most often the problem is caused by:
Varieties of yellowing
Cucumber leaves can turn yellow in different ways. By carefully examining the plants, you can determine exactly why the yellowing occurred and figure out how to get rid of the problem.
Leaves turn yellow and curl
| Possible problem | What to do |
| Lack of nutrients (particularly nitrogen) | Fertilize with complex mineral fertilizer, which contains nitrogen. |
| Powdery mildew | Spray the plants with a one percent solution of Bordeaux mixture and regularly ventilate the greenhouse |
| Pests | Examine the back of the sheet. If you detect the presence of aphids, spider mites or other pests, treat them with appropriate preparations |
| Burn or hypothermia | If cucumbers grow in closed ground, adjust it temperature regime, provide shade from the sun and make sure that the leaves do not come into contact with the glass of the greenhouse. Water open ground plants in a timely manner and cover them with spunbond or plastic film in case of cold weather. |
| Dry air | Follow the watering schedule and control air humidity |
| Viral disease | If you comply with all the maintenance conditions, the plants are healthy and provided with nutrients, but their leaves continue to turn yellow and deformed - most likely the cause is viral disease. Affected cucumbers should be dug up and destroyed to prevent the spread of the virus. |
The lower leaves turn yellow
| Possible problem | What to do |
| Lack of sunlight | Provide the cucumbers with good light, but make sure that the plants do not get sunburned |
| Improper watering | Adjust the watering mode |
| Hypothermia | If cucumbers grow indoors, be sure to close the greenhouse at night in the summer, and in early spring and heat the room in late autumn. Seedlings in open ground if there is a threat of cold weather, you need to cover it with agrofibre or plastic film |
| Lack of mineral fertilizers (potassium, magnesium, phosphorus) | Fertilize with complex fertilizers |
| Fungus (fusarium, pythiosis, etc.) | Remove and burn the affected leaves, and then treat the cucumbers with a fungicidal preparation or a one percent solution of Bordeaux mixture |
| Natural aging | If you are seeing dieback lower leaves at the end of the growing season, this is most likely normal and no action is required on your part |
Simultaneous yellowing of leaves and ovary
The edges of the leaves turn yellow
Leaves turn yellow in spots
| Disease | Symptoms | What to do |
| Anthracnose | The spots are round, with blurry edges, yellow-brown in color, and with increasing humidity, pinkish pads appear on them. The stem and petioles are covered with concave oblong sores | Treat the plants with a one percent solution of colloidal sulfur. After 2 weeks, spray with Bordeaux mixture. Treat areas affected by anthracnose with a solution copper sulfate and sprinkle with crushed coal |
| Downy mildew | Rounded spots appear on the upper side of the leaf. yellow spots, and the lower one is covered with a white coating. Affected leaves die | In the evening, spray the cucumbers with a solution of Oxychom (20 grams per bucket of water) or Rizoplan (2 tablespoons per bucket of water). Watering the plants is stopped for a week. In the fall, all cucumbers are dug up and destroyed; it will be possible to replant the crop in the same place no earlier than after 7 years |
| Sunburn | Cucumber leaves turn yellow, but there are no obvious signs of disease | Water the plants only in the evening and never spray them in direct sunlight |
How to prevent yellowing
To prevent cucumber leaves from turning yellow, use special treatments:
Periodic treatment with biological products (for example, Trichodermin)- they kill pathogens and at the same time are completely safe for both people and animals. And to minimize the likelihood of diseases, you need to observe crop rotation - do not plant cucumbers for several years in the same place and avoid planting them after zucchini or pumpkin.
Not in all cases, the leaves on cucumbers turn yellow due to a lack of nutrients. When observing plants, you need to pay attention to how the leaves acquire a yellow color - in spots, completely, at the edges, turn yellow and wither, between the veins.
As you can see, there are many options and they all occur for different reasons, determining which is the main task experienced gardener. When the leaves of cucumbers turn yellow, what to feed them with? main question, because The reasons may not be due to nutritional deficiency.
The reasons for the sudden yellowing of foliage on cucumbers can be arranged in descending order to make it easier to look for the problem:
- Watering is carried out incorrectly or insufficiently. Cucumbers – tropical plants. They must receive moisture from the soil and from the air. The soil layer must be moistened and not flooded with water, to a depth of about 10 cm.
- Violation of technology foliar feeding– spraying during the day under the scorching rays of the sun leads to sunburn, complicated by the presence of chemicals in the solution.
- Lack of microelements. It is advisable to know what type of soil on the site belongs to in order to suggest a lack of substances. Ideal soil does not exist, it must be created with your own hands, skills, through constant observation of plants.
- Lack of basic nutrients - nitrogen, potassium or phosphorus. Moreover, phosphorus can have a significant effect on the absorption of nitrogen, and only with a lack of nitrogen will the foliage begin to turn pale and then turn yellow.
- Spring frosts and temperature changes have a negative effect on cucumber seedlings.
- Diseases of cucumbers - viral or fungal. Invasion of garden pests.
- Using unsuitable fertilizers with chlorine or the presence of aluminum and manganese salts in excess.
- Natural processes when old leaves gradually die off.
As can be seen from the list possible options, you will have to think about what was done incorrectly, at the wrong time, or not done at all.
Improper watering
The first place in the causes of yellowing of leaves is occupied by improper or insufficient watering. Cucumbers prefer humidity in the air, but the roots should not be flooded. This leads to oxygen starvation and root system begins to rot, nutrients do not reach the leaves and the plant dies.
Insufficient watering in hot summers stops the activity of soil microorganisms that absorb nitrogen and make it available to the root system of cucumbers. There is sufficient nutrition in the soil, but without bacteria the nutrition process is disrupted. Without nitrogen, the leaves turn yellow. A characteristic feature wilting occurs - the leaves and shoots of cucumbers droop.
Solution to the problem: dig up the soil 10 cm deep and see what condition it is in. First you need to set up watering and observe for a couple of days. If the situation improves, continue to follow the norms and hydration regime. To better retain water in the soil, it can be mulched with straw and leaves.
Incorrect spraying
For foliar treatments you need to choose morning time so that the leaves have time to dry by lunchtime. Or evening, when the sun completely sets. Presence chemical substances in solution causes a burn. Most likely there will be spots on the leaves of cucumbers yellow color, which then dry out and turn into holes.
Lack of microelements
Micronutrient deficiencies can be divided into two groups:
- the first, which causes yellowing and death of old leaves;
- the second is problems at the growth points, that is, yellowing of young leaves and shoots.
Lack of zinc and magnesium appears on older leaves. In this situation, the plant tries to move nutrients to young leaves and retain them. The same goes for nitrogen, potassium and phosphorus. A lack of magnesium causes a complete loss of pigment - cucumber leaves turn white - completely or in places.
Video: A simple way to prevent cucumber leaves from turning yellow
Deficiency of calcium, iron, sulfur, boron, manganese and copper is more detrimental to plants because it causes stunting. Chlorosis or necrosis of the leaf blade occurs.
- The top is constantly withering - there is not enough copper.
- The veins darken, the leaf curls from the top to the base - lack of boron.
- Young leaves curl downwards, the leaf blade breaks - lack of calcium.
- Cucumber leaf looks like chessboard color – lack of manganese.
- Veins are lighter than the leaf - lack of sulfur.
- Yellowing between the veins is an iron deficiency.
How to feed cucumbers so that the leaves do not turn yellow from a lack of microelements? The most in a fast way will buy concentrate, dilute it and apply foliar feeding.
You can feed cucumbers in a greenhouse with organic substances containing the full composition of microelements. Such a substance is wood ash– the best folk remedy, which contains about 30 different components, not counting potassium and phosphorus.
For this you need dilute and infuse 300 g of the substance in a bucket of water. The infusion needs to be kept for 3-4 days so that the necessary microelements are transferred into the liquid, which is then watered at the roots of the plants.
Important! The use of ash is useful not only from the point of view of fertilizing, but also as a way to combat fungus and pests
Cucumber fruits turn yellow - what to do
If the ovaries or young fruits turn yellow, this means that there are more of them on the plant than it can feed. This process can be stopped by feeding with yeast a couple of times during the season. The yeast fungus, entering the soil, serves as food for soil bacteria. This serves as additional nitrogen fertilizer, and a safe one.
Lack of essential nutrients in cucumbers
If the cucumbers have turned yellow due to a lack of nitrogen, which is often observed on sandy soils, then you can feed them with urea leaf by leaf. Continue to apply nitrogen fertilizers in smaller doses, but more often - sandy soils lose nutrients faster. Nitrogen starvation of cucumbers is manifested by a light green color of the leaf over the entire area of the plate.
The root system of cucumbers may be underdeveloped due to a lack of phosphorus. You need to inspect the root; if it turns yellow, then it’s time to apply fertilizer. It is advisable to use phosphorus first to help the roots. Next comes complex mixtures.
If the yellowing started from the old leaves along the edges, and the edges are drying out, then you need to figure out how to feed the cucumbers so that they get potassium. This can be potassium sulfate, potassium salt, ash solution, green fertilizer.
