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Cucumber plants turning yellow and brown


Why are my cucumber leaves turning yellow? |

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'Why are my cucumber leaves turning yellow?' – it's an enduring question amongst gardeners who grow this quirky fruit – but the answer is simple. 

Knowing how to grow cucumbers is the same as any other plant: meaning light and water levels are crucial to healthy growth. So, if you notice your cucumber leaves turning yellow, it is likely down to one of these factors. 

Whether you're learning how to grow cucumbers vertically – or you're growing from the ground or pot – your fruit is not immune from yellow leaves. Here's exactly what causes discoloring and how to avoid it in your produce. 

Why are my cucumber leaves turning yellow? 

(Image credit: GettyImages)

According to Tom Hilton, director of outdoor and indoor garden specialists at National Greenhouse , yellowing occurs when the leaves lose chlorophyll – a pigment that gives plants their green color. Chlorophyll also aids photosynthesis (allowing the plant to convert light into energy).  

'The minute you see those cucumber leaves yellowing, it's time to take action,' Tom says. 'The main causes of this discoloration can be issues with the soil, overwatering, and of course, sunlight problems.' 

Alongside these key problems, Oliver Hill, Founder of Garden List , suggests that pets may be responsible for yellowing leaves. 'Aphids, whiteflies, and cucumber beetles are all common pests that can damage cucumber plants,' she adds. 'If you suspect that your cucumber plant is suffering from one of these problems, be sure to take action immediately to keep your plant healthy.'

(Image credit: GettyImages)

How to stop cucumber leaves from turning yellow

Knowing when to plant cucumber seeds is one way to set your fruit up for success, but perfecting a care routine is equally impactful. Here's what the experts recommend.

1. Maximise sunlight 

Your cucumber plants should receive at least six hours of sunlight daily – to boost their health and avoid discoloring. If your cucumbers aren’t getting enough sunlight, they will likely droop, and yellowing will appear in the leaves. Therefore, Tom suggests moving your cucumbers from shady spots (where possible) to a sunnier area of your garden. 

2. Avoid overwatering

Emma Loker from DIY Garden explains that overwatering is one of the most common reasons your cucumber leaves turn yellow. Knowing when to water plants is key to their success, but what is the best time for the job? The expert recommends watering in the morning – avoiding the leaves as this 'encourages diseases.'

However, 'the best way to water cucumber plants is using a drip irrigation system or soaker hose,' Emma says. This allows you to keep track of the water levels, so your crop is never at risk of drowning. 

3. Monitor nutrients in the soil

Your cucumber plant's diet is another crucial issue in regard to yellowing. 'You should check the cucumber plant is getting the right soil nutrients,' Tom instructs. 'Potassium and nitrogen are two key ingredients they love, helping to encourage growth in foliage and keeping the leaves healthy and green.

To ensure your cucumber receives a good diet, you can invest in a fertilizer that fills the soil with everything they need to grow healthier. 

(Image credit: Getty Images)

Should I cut yellow leaves off cucumber plant?

Yes, it is better to remove any leaves that have turned yellow as they may limit light from reaching the healthy part of your fruit. It will also encourage air circulation, which is beneficial to the plant overall. However, after removing the leaves, it is important to follow the prevention steps above to allow other leaves to grow healthier for a tasty crop.

What do overwatered cucumbers look like?

Overwatered cucumbers often show signs of yellowing leaves first. As Emma suggests, finding the correct water levels is imperative to your fruit's success, and if you're overwatering them, your leaves will suffer. To avoid this, you should water slowly in the morning or set up a drip irrigation system that monitors the water levels automatically. 

Megan is the News and Trends Editor at Homes & Gardens. She first joined Future Plc as a News Writer across their interiors titles, including Livingetc and Real Homes. As the News Editor, she often focuses on emerging microtrends, sleep and wellbeing stories, and celebrity-focused pieces. Before joining Future, Megan worked as a News Explainer at The Telegraph, following her MA in International Journalism at the University of Leeds. During her BA in English Literature and Creative Writing, she gained writing experience in the US while studying in New York. Megan also focused on travel writing during her time living in Paris, where she produced content for a French travel site. She currently lives in London with her antique typewriter and an expansive collection of houseplants. 

Cucumber Leaves Turning Yellow: What to Do?

There are many reasons behind yellow cucumber leaves. These could include disease, pest attack, water levels, light, or nutrient deficiency. We are here to explain why this happens and the best solutions to prevent it.

Cucumbers are a popular plant for home gardeners to grow. They are tasty, nutritious, and great for the summer season.

Although cucumbers are simple to grow, they can become susceptible to many problems. When these issues become more severe, the vegetable gets dry faster.

Contents

Cucumber plants yellowing is not a minor issue. In some cases, the plant may die before producing fruits.

Below are some reasons you might see cucumbers with yellow spots:

1. Light

Light can be the main reason behind yellow cucumber leaves. Whether you’re growing indoors or outdoors, make sure they are getting enough sunlight. Cucumbers need six to eight hours of sunlight daily.

What to Do?

2. Water Levels

Your cucumber plants must have the right amount of water. Overwatering or underwatering can be quite problematic for your cukes.

Overwatering results in a lack of oxygen in roots. This also makes cucumber leaves turn yellow and start wilting.

Insufficient water can also be responsible for yellowing leaves on cucumber plants. Remember, the plant requires one to two inches of water every week.

What to Do?

3. Chlorosis

Chlorosis is a condition that causes plant leaves to produce insufficient chlorophyll. As you know, chlorophyll is the green leaf pigment that grabs sunlight to fuel the production of food. Thus, without enough chlorophyll, cucumber starts turning yellow and starving.

What to Do?

4. Pests

Pests are also one of the reasons behind cucumber leaf discoloration. Common pests that attack cucumber include potato leafhoppers, spiders, aphids, mites, or whiteflies.

a) Spider Mites

Spider mites, whether adults, nymphs, or larvae, can wreak havoc on your cucumber plants. They damage the leaves by sucking the sap from them. These insects stay on the underside of leaves, where they leave a fine silver web.

Mites appear in late June through August. They are more widespread in dry and hot weather. Adult spider mites are very small (around 1/50 inch). They have yellow to dark crimson coloring.

Feeding marks display as light dots on the leaves. As the feeding progresses, you’ll see yellow cucumber leaves. In worst cases, it may dry out and fall off.

What to Do?

b) Whiteflies

An infestation of whiteflies can also lead to yellow cucumber leaves. Several species of whiteflies can attack cucumbers. Greenhouse and Silverleaf varieties cause the majority of destruction. They are usually found on the underside of leaves as they love to feed on sap.

What to Do?

c) Aphids

Sometimes, your cucumbers suffer from aphid infestation. These little bugs can cause them to become stunted and mottled. Aphids are small oval insects with a long mouth.

These yellow and green insects suck the fluids out of plants. They are often challenging to control. That is why it is pivotal to get rid of these tiny insects early. Cucumber leaves bent downwards at the edges have likely been attacked by aphids.

What to Do?

d) Potato Leafhopper

The potato leafhoppers are insects much larger than the bugs mentioned already. They stay on the leaves of cucumbers to suck the sap out of them. As they feed, they inject toxins. This makes the leaves weak and turns yellow.

Once the leaves get too much damage, they fall from your cucumber vine. This can also hinder the production of cucumbers. Moreover, these pests also leave behind a sticky substance known as honey crew. It causes sooty mold to develop.

What to Do?

5. Plant Diseases

Bacterial and fungal diseases are often responsible for yellow spots on cucumber leaves. They will also lead to the death of plants. Common cucumber diseases include the following.

a) Mosiac Virus

The mosaic virus affects more than 150 plant varieties, including cucumber. They live in the soil, so they can keep infecting other plants throughout the year.

This virus causes cucumber leaves to wrinkle or curve downward with yellow or brown spots. If you leave your infected plants in the garden untended, the virus will spread via leafhoppers and aphids.

What to Do?

There is no way to treat plants infected with the virus. All you can do is…

b) Verticillium Wilt

This is a wilt disease caused by six species of Verticillium fungi. The pathogen can survive in the soil for as long as eight to 10 years. You can notice the symptoms on only one side of the cucumber.

c) Downy Mildew

Downy mildew is one of the most destructive foliar diseases. Pseudoperonospora Cubensis causes it. The telltale signs include yellow spots on the cucumber leaves and gray mold underneath. These spots turn brown later on.

Remember, humid and cool conditions encourage the development of this plant disease.

What to Do?

d) Fusarium Wilt

Fusarium wilt is a ground-dwelling disease caused by the Fusarium oxysporum f. sp. cucumerinum. This fungus can thrive in the soil for long periods. It causes cucumber leaves turning yellow around edges and then inwards. The virus develops on older cucumber plants and leaves.

What to Do?

e) Anthracnose Leaf Spot

Colletotrichum Orbiculare fungus causes Anthracnose. The pathogen can attack all types of cucurbits, but they target cucumbers, watermelons, and muskmelons. Anthracnose infection starts with irregular water-soak leaf spots. These spots turn yellow and then change to brown color.

This disease develops in moist and warm environmental conditions.

What to Do?

6.

Nutritional Deficiency

Cucumbers also need many nutrients to thrive and grow. When they are not getting enough of these nutrients, chlorosis occurs. To determine whether your plant is nutrient deficient, get your garden soil tested.

Below are the common deficiencies that can cause yellow cucumber leaves.

a) Nitrogen

Nitrogen is a crucial nutrient for cucumber plant growth. Leaves will turn yellow at the tips and along the central veins due to decreased nitrogen levels. Nitrogen deficiency also inhibits plant growth.

What to Do?

Note: Always follow instructions on your fertilizer. Avoid using too much fertilizer in the soil to prevent plant reproduction.

All these tips will prevent cucumber leaves from turning yellow.

b) Phosphorous

Do you see bronze or deep yellow cucumber leaves? If yes, this indicates a phosphorous deficiency. Phosphorus is vital for the normal development of reproductive organs and roots. Its deficiency can stop fruit production and hinder growth. Phosphorus-deficient plants are stunted and have weak roots.

What to Do?

c) Potassium

The potassium deficiency in cucumber first occurs on older leaves. They make cucumber leaves turn yellow at the edges and tips. After that, it spreads between the primary veins towards the center of the leaf.

Young leaves tend to look dull and small. Cucumber fruit appears narrow at the end of the stem. It gives the fruit a club-shaped appearance.

What to Do?

d) Zinc

Zinc deficiency causes cucumber leaves to turn yellow and droopy. Leaf size also gets very small. Moreover, it blocks the cucumber’s growth.

What to Do?

e) Iron

Iron deficiencies cause young cucumber leaves to develop interveinal chlorosis. This is the yellowing with green veins, but the older leaves stay green.

What to Do?

There are two ways to fix it: either treat the soil or the cucumber plants.

Note: You can even do a soil pH test and amend it to get it below 7.

f) Calcium

When cucumber grows under humid conditions, they can also get calcium deficiencies.

Other factors can include…

You can spot the deficiency in the young and growing leaves with low rates of transpiration. Growing leaves look distorted and may cup downwards. Calcium deficiency also causes yellow cucumber leaves to be tasteless.

What to Do?

g) Magnesium

Magnesium deficiency causes older cucumber leaves to turn yellow and cause veins. In case of severe deficiency, a light tan burn will occur in the yellow areas. It also reduces fruit yield.

What to Do?

Conclusion

Growing cucumbers at home allow you to have this crunchy treat available year-round. Cucumber leaves turning yellow and dying shows that something is wrong with plants. It can happen to every gardener from time to time.

By implementing our tricks, you can save your vine crops. When dealing with cucumber plant problems, talk with a skilled local agricultural specialist. The expert can offer you more tips to treat yellow leaves on cucumber plants.

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what to do, why they appear, how to treat and process in a greenhouse and open field

Interesting facts about growing cucumbers

India is the birthplace of cucumbers (1). There they often grow in tropical and subtropical forests, climbing trees. And their origin leaves a mark on the requirements for growth.

Soil Neutral, slightly acidic (Ph 6.2 - 7)
Temperature0010
Watering every other day
Care Weeding, Watering, top dressing, formation, garter
Flowers are divided into male (without ovary) and female (there is a ovary in the form of crumbs)
Pollination There are varieties and hybrids pollinated by insects and parthencarpic (form ovaries without pollination (2)

Why yellow spots appear on cucumber leaves

Most often, the cause lies in the disease, the causative agents of which can be pathogenic fungi, bacteria or viruses. However, the influence of external factors should not be dismissed from the shields either.

Diseases

Yellow spots on cucumber leaves can be signs of several diseases.

Bacteriosis (angular spotting). The causative agent is the bacterium Pseudomonas syringae. Spots of a characteristic angular shape appear on the reverse side of the sheet. They are weeping, light brown in color.

Cucumber mosaic. The causative agent is the cucumber green mottled mosaic virus (GGMV). This disease usually manifests itself in the phase of 3-4 pairs of leaves. Leaf blades are covered with light green and yellow spots that develop into a mosaic. The leaves shrivel and dry up.

Cucumber mosaic. Photo: shutterstock.com

Black leg. Pathogens - how many types of fungi: Rhizoctonia solani, Fusarium solani, etc. First, the cucumber stem turns black, then yellow spots appear on the leaves.

Anthracnose. The causative agent is the fungus Colletotrichum orbiculare. The spots on the leaves are extensive, often depressed, gradually openings form in their place.

Anthracnose. Photo: shutterstock.com

Ascochitosis. The causative agent is the fungus Ascochyta cucumis. Along the edges of the leaves, extensive watery spots of yellow-gray color are formed, which gradually dry out and crumble. The disease can also affect fruits.

Downy mildew. The causative agent is the fungus Pseudoperonospora cubensis. Numerous yellow spots appear on the leaves, inside which brown patches gradually appear. The area of ​​spots grows rapidly, capturing the entire plant.

Downy mildew. Photo: shutterstock.com

Brown spot. The causative agent is the fungus Cladosporium cucumerinum. Small yellow spots on the leaf plates grow very quickly, inside the spots the leaf dries and crumbles. More often the disease occurs in a greenhouse.

Pests

Yellow spots on cucumber leaves may be signs of pests. Most often, plants are harmed by spider mites, aphids, and whiteflies. Small yellow spots appear on the leaf blades at the puncture points, through which the pests suck out the juice of the plant.

If cucumbers are infected with spider mites, a thin web with mites crawling on it is clearly visible on the back of the leaves.

External factors

Lack of nutrients. Yellow spots on the leaves often appear due to the lack of micro and macro elements in the soil. For example, with a lack of magnesium and potassium, iron, manganese or copper.

Sunburn. If cucumbers are watered in bright sunshine, water drops on the leaves turn into convex lenses, and the same effect is obtained as when the beam passes through a magnifying glass - the leaf under the drop gets burned.

Hypothermia. Early or late frosts on the ground sometimes cause frostbite on the leaves, resulting in yellow spots on them.

What to do if yellow spots appear on cucumber leaves

First you need to understand what caused this phenomenon. After all, as we saw above, yellow spots on cucumber leaves are not always the result of a disease. Therefore, try to exclude all other factors: think about whether you are fertilizing the soil enough, whether you violate the irrigation regime, whether there were frosts before the spots appeared. If you come to the conclusion that you overlooked the plantings, just start caring for the cucumbers correctly, and the spots will disappear.

It is also easy to detect pests: whiteflies usually hover over cucumber bushes in large numbers, and aphids and spider mites stick to the leaves and stems of plants. In this case, you will need to treat the plants with natural or chemical insecticides.

If the above reasons are eliminated, then it becomes clear that your cucumbers are still sick. The most common pathogens are fungi, but bacterial and viral diseases also occur. To combat them, cucumbers need to be treated with fungicides.

How to treat and process cucumbers from yellow spots on the leaves

The axiom “it is easier to prevent a disease than to cure” works not only for people, but also for plants. Therefore, in order for your cucumbers to always be healthy, green and bear excellent fruit, you need to properly care for them and be sure to carry out the prevention of diseases and pests.

For these purposes, there are both folk remedies that have been tested for centuries, as well as modern chemical preparations. The first ones are good because they are completely harmless, and the ingredients for their preparation are cheap and available. These are soap, soda, medicinal herbs, mustard, ash, milk, etc. However, such agents act rather weakly, therefore they are more suitable for the prevention or treatment of plants in the early stages of infection.

The same can't be said about chemicals used to control pests, pathogenic bacteria, viruses and fungi. They act quickly, effectively, however, as a rule, they are poisonous, therefore they require very careful handling.

Do not forget that for the greenhouse and open field use different means of treatment (3).

In the greenhouse

Any folk remedies are suitable for processing cucumbers in protected ground, and Bordeaux mixture is most often used among chemical preparations - a truly universal “medicine” that protects plants from a number of diseases.

From fungicides (drugs for fungal and bacterial diseases) suitable for greenhouses: Fitosporin (black leg and a number of other fungal diseases), HOM (complex of fungal diseases), Previkur energy (peronosporosis).

Suitable insecticides for greenhouses (against pests): Bitoxibacillin (spider mite), Bison, Imidor, Phytoflavin (whitefly, aphid) (4).

In the open ground

If your cucumbers grow in an open-air garden, then any folk remedies (soap solution, ash, tobacco dust, whey, herbal decoctions, etc. ) are also suitable for processing them.

As for chemical and biological preparations, the following fungicides can be used for outdoor cucumbers: Abiga-peak (peronosporosis, anthracnose, bacteriosis), Oxyhom, Baksis, Intrada, Signum, Orwego (peronosporosis) (4). And from insecticides it is worth using Confidor, Fufanon Expert (whitefly, mites), MatrinBio (aphids, mites), Ultor (spider mites, aphids) (4, 5).

Popular questions and answers

We talked about the nature of yellow spots on cucumbers with candidate s.-x. Sciences, scientific agronomist, director of the nursery "Flower of the Urals" Daniil Kostylev.

How to treat cucumbers from yellow spots on the windowsill at home?

First of all, you need to understand the cause of the spots. If they are uneven, with subsequent darkening, then these are diseases - we treat them, for example, with biological preparations (Fitosporin-M, Gamair, etc.).

How to treat cucumbers from yellow spots with a lack of elements?

If yellowing of the edges of the leaves, this may be a potassium deficiency - fertilize with potassium monophosphate (2 g per 1 liter of water), and if yellowing throughout the leaf with green veins - there is not enough nitrogen or iron, we feed fertilizers with these elements.

Will folk remedies help with yellow spots on cucumber leaves?

If folk remedies are used proactively in advance, then this may well protect plants from most fungal diseases. As a rule, at home, it is safest to wipe the leaves with a mild soapy solution, which will protect not only from fungi, but also from pests.

References

  1. Renner SS., Schaefer H., Kocyan A. Phylogenetics of Cucumis (Cucurbitaceae): Cucumber (C. sativus) belongs in an Asian/Australian clade far from melon (C. melo) // BioMed Central Journal, Vol. 7, 2007
  2. Zhukovsky P.M. Cultivated plants and their relatives. Systematics, geography, cytogenetics, immunity, ecology, origin, use. Ed. 3rd, revised. and additional // L.: Kolos, 1971 - 752 p.
  3. Demidova L. Diseases of cucumbers in protected ground // L.: Kolos, 1975 - 63 p.
  4. State catalog of pesticides and agrochemicals approved for use on the territory of the Russian Federation as of July 6, 2021 // Ministry of Agriculture of the Russian Federation https://mcx. gov.ru/ministry/departments/departament-rastenievodstva-mekhanizatsii- khimizatsii-i-zashchity-rasteniy/industry-information/info-gosudarstvennaya-usluga-po-gosudarstvennoy-registratsii-pestitsidov-i-agrokhimikatov/
  5. Pankratova A.B. Cucumbers. Growing in the soil, greenhouse, on the windowsill // M.: Sotsium, 2012 - 60 p.

in greenhouse and open field. What to do if the leaves of cucumbers turn yellow.

An attentive gardener, by the first signs of "malaise" of cucumbers, can make the correct diagnosis and take action in time. Healthy plants delight with their appearance: they have large leaves of rich green color. As soon as the cucumber leaves begin to turn yellow, you need to find the cause and eliminate it.

As soon as the leaves began to turn yellow - look for the reason!

Cucumber leaves turn yellow for several reasons:

Transplant stress

After planting seedlings in a permanent place, cucumbers often turn yellow and wither leaves. The reason for this is stress from the transplant. Cucumbers, like all pumpkins, have fragile roots, so they endure transplantation extremely painfully. Cucumber seedlings are best grown in individual containers with a volume of at least 1 liter.

Cucumber seedlings are planted in a permanent place as soon as 3-4 true leaves form on the plants. When planting overgrown seedlings that have already bloomed, the plants get sick for a long time, the leaves of the cucumbers turn yellow and dry out.

In order to reduce the stress of plants from transplanting, it is necessary to sow seeds no earlier than a month before planting seedlings in a permanent place.

So that the seedlings do not outgrow, the plants are treated with growth regulators, such as the drug "Krepen" . It stimulates the development of the root system and inhibits the pulling of seedlings. The drug improves the survival of seedlings and reduces stress from transplantation.

After planting seedlings, cucumbers need to be shaded for a week or two, while the plants take root in a new place. During this period, the soil should be moderately moist, the drying of the earth in the root zone is not allowed. Dense spunbond will save plants from the scorching rays of the sun.

Cold stress

At the beginning of summer, the weather often brings unpleasant surprises in the form of return frosts, unexpected cold snaps, squally winds or hail. Cucumber, this tropical vine, is difficult to perceive such cataclysms. At temperatures below + 8 ° C, cucumbers fall into a state of shock, the roots stop working, the plant “freezes” and waits for the heat to return.

If return frosts caught cucumbers in a greenhouse or in open ground, then they need to be saved by all possible means. In unheated greenhouses, cucumbers are additionally covered with a dense spunbond; in the open field, arcs are installed above the cucumbers and covered with plastic wrap.

After the end of the cold weather, the plants look sad for some time, the cucumbers have small shriveled leaves, the plants do not burst into growth. During this period, it makes no sense to do root dressing, because. Cucumber roots are under stress and unable to absorb nutrients.

After a cold snap, frost or hail, it is useful to treat the plants with an anti-stress preparation with vitamins and amino acids, this will help them regain strength and recover from shock. Treatment is carried out with preparations "Epin" , "Zircon" , "Vitamin" , "Amicid" , etc.

Heat stress

Despite the fact that the cucumber is a heat-loving plant, it can be too hot for it. The optimum temperature for cucumber growth is +22-25°C during the day and +16-18°C at night. However, such ideal conditions are rarely created. At the height of summer, the daytime temperature goes off scale and rises to + 30-32 ° С in the shade, while in the sun or in a greenhouse it is + 40-45 ° С. In such conditions, cucumber leaves turn yellow and wither, which is not surprising.

In the southern regions, it is better to grow cucumbers in partial shade, planting them in places that are illuminated by the sun for only half a day. To save cucumbers from the scorching sun will help a special mesh. It is stretched over the beds, and the plants are in a light lacy shade. Unlike dense spunbond, the mesh is well blown, so windage is not created, and the shelter does not fly away in strong gusts of wind.

To reduce the temperature in the greenhouse, it is covered on top with a dense white spunbond or stretched inside the greenhouse, under the ceiling. In hot summers, you can whitewash the ceiling of the greenhouse with a solution of chalk, this will reduce heating, because. the sun's rays will be partially reflected.

Single yellow spots on the leaves of cucumbers can form as a result of sunburn, if water gets on the leaves during morning watering. In a glass greenhouse, plants can get burned from touching hot glass.

Wrong watering

Cucumbers are extremely demanding on watering. With prolonged drought, cucumber leaves turn yellow, leaf plates coarsen, and greens are bitter. For cucumbers, soil moisture is more important than its friability and breathability.

But this does not mean that cucumbers can grow in damp, dense soil, everything needs a measure. In rainy summers, when the ground does not have time to dry out, root rot of cucumbers may develop.

Most likely, the leaves turned yellow from insufficient watering

Ideally, the soil under cucumbers should always remain slightly moist in the root zone, at a depth of 10-15 cm. In hot weather, cucumbers are watered daily or every other day. Watering is carried out under the root, trying not to erode the soil in the root zone.

It is better to water cucumbers in the evening: in the open field, this allows the roots to be saturated with moisture during the cool night hours, and in the greenhouse, evening watering helps to increase air humidity, which is good for cucumbers.

For weekend summer residents, daily watering is impossible, so they cannot do without mulching. A layer of organic mulch 7-10 cm thick protects the soil from overheating and retains moisture until the next watering. In addition, when using mulch, the soil does not compact as much, so there is no need to loosen it.

Mulching with organic matter must be combined with the use of biological products. Outdoors, as soon as the heat turns to rain, the organic mulch will begin to rot and become a favorable environment for the development of pathogenic microflora. In greenhouses, the use of biopreparations is no less important, because. soil in a greenhouse always contains more pathogens.

Before mulching, "Trichoderma veride" or a complex biological product 9 is embedded in the top layer of the earth0204 "Atlas helper bacteria" . Trichoderma in the composition of these preparations accelerates the decomposition of organic matter and inhibits the growth of pathogenic fungi. The introduction of trichoderma into the soil reliably protects cucumbers from root rot.

Lack of power

The leaves and fruits of cucumbers quickly react to the lack of some nutrients. Gardeners need to learn the "language" of plants in order to distinguish nutritional deficiencies from signs of the onset of disease.

Nitrogen

Cucumbers consume a lot of nitrogen. When planting cucumbers, the bed is filled with humus or complex mineral fertilizers are applied. Cucumbers quickly use up the supply of nutrients and already in the middle of summer they begin to starve. In addition, nitrogen and potassium - two of the most important elements for cucumber growth - are quickly washed out of the soil due to frequent watering.

The pale green color of the leaves, thin lashes and narrow-tipped fruits indicate that cucumbers are deficient in nitrogen. Feeding with urea or a liquid organic fertilizer such as mullein infusion, chicken manure or fermented green manure quickly eliminates nitrogen deficiency.

Potassium

If the cucumber leaves turn yellow around the edges, and the greens swell and take on the shape of a light bulb, it’s a lack of potassium. Excessive application of nitrogen fertilizers leads to a deterioration in the absorption of potassium.

Nitrogen top dressing is better to alternate with potash. Organic potassium is found in wood ash. Granular ash is embedded in the topsoil, it will gradually dissolve with watering and rain. Wood ash can be applied as a solution under the root at the rate of 1 glass of ash per bucket of water.

Magnesium

Chlorosis on the leaves indicates a lack of magnesium, iron or zinc. With a deficiency of these elements, the veins of the leaf remain green, and the space between them brightens.

Chlorosis on the lower leaves indicates a lack of magnesium. Plants are able to reuse magnesium when it is deficient, they take it from old leaves, directing it to the growth of young ones.

Magnesium is an important trace element involved in photosynthesis and other processes. Regular use of complex mineral fertilizers with magnesium in the composition provides plants with a balanced diet.

Cucumbers need to be fed once every two weeks. Root fertilizing "Healthy Turbo for cucumbers, pumpkins, zucchini and squash" provide plants with all the necessary nutrition during the summer. They contain the main elements in the right proportions: 12% nitrogen, 6% phosphorus and 28% potassium, as well as magnesium, boron, zinc and other trace elements.

Iron

If chlorosis appears on young leaves, the plant lacks iron or zinc. It is very easy to eliminate the lack of iron, it is enough to treat the cucumbers with iron chelate along the leaf or use a special fertilizer with nitrogen and iron - "Sequestren Turbo" . Iron deficiency impairs nitrogen absorption, this drug quickly eliminates both problems.

Tightness and aging

With a thickened planting of cucumbers, some leaves are in deep shade. This is often the reason why cucumber leaves turn yellow in a greenhouse. They cannot get to the sun through dense thickets, so photosynthesis in the leaves is worse, they turn yellow and gradually die off.

There is nothing wrong with this, but you need to take into account the signals of the plant about thickening. In dense foliage, some flowers remain unpollinated, and the ovaries turn yellow and fall off. In addition, with excessive thickening, the plants are less ventilated, therefore, with increased soil and air moisture, the rapid spread of fungal diseases begins.

When growing cucumbers on a trellis, they are planted at a distance of 35-40 cm from each other and form into one stem with shortened side shoots. With this method of formation, the plant looks like an inverted pyramid. The lower part of the stem should be free from stepchildren and leaves for good air circulation.

In the open field, cucumbers are allowed to grow freely, without shaping, spreading the lashes in all directions. To avoid thickening, it is necessary to maintain a greater distance between plants in a row - 60-90 see

The aging of the lower leaves is a natural process. As the cucumber grows, it takes nutrients from the lower leaves and sends them to the growth of new shoots and the formation of ovaries. Old yellow leaves on cucumbers should be gradually removed.

Cucumber diseases

Cucumber leaves often turn yellow and curl due to fungal diseases. As a rule, they appear closer to August, when cold nights begin, and abundant condensation forms on the leaves of the cucumber. But in a rainy warm summer, fungal diseases can attack plants as early as June - July.

Powdery mildew

Powdery mildew appears as white spots on the upper side of the leaf. As the disease spreads, the spores of the fungus cover the entire leaf with a powdery coating, after which the leaves dry out and die. Powdery mildew spreads not only in rainy summers, high temperatures also contribute to the development of the disease.

The causative agent of powdery mildew spreads very quickly, but if it was possible to notice the development of the disease at an early stage, it can be stopped. Any copper-containing preparations are effective against powdery mildew, such as "HOM", "Oksihom", "Abiga Peak" , 1% copper sulfate . Copper is not too toxic, but it is still advisable to first remove all greens that have reached the size of a gherkin, and then process them so that there are 3-5 days before the next harvest.

In the fight against powdery mildew, sulfur-based contact fungicides, such as "Thiovit Jet" , are effective, sulfur is harmless to humans, greens can be eaten the next day after processing. It should be borne in mind that in the heat, sulfur vapor causes burns on the leaves. Processing is carried out at a temperature from +27°C to +32°C. For a longer effect, you can treat with a systemic contact preparation Serpen .

Downy mildew or downy mildew

Peronosporosis is a common disease of cucumbers, it also affects onions grown for turnips. The causative agent of peronosporosis lives in the soil, gets on the leaves with drops of dew, rain or water during irrigation. The disease begins with the lower leaves, quickly spreads to the entire plant.

Peronosporosis manifests itself in the form of yellow spots on cucumber leaves, which are limited by the veins of the leaf, which is why the shape of the spots is not round, but more like a honeycomb. The spots quickly capture the entire leaf, in a matter of days the leaves of the cucumber turn yellow and dry out.

The causative agent of peronosporosis is similar to the causative agent of late blight, these are oomycete fungi, which require special fungicides to combat. Peronosporosis and phytophthora are partially suppressed by copper, therefore it is included in the preparations as the second component, for example, in fungicides "Ordan" and "Bronex" .

Treatment for peronosporosis should be started at the first sign of the disease and repeated twice with an interval of 10 days. Preparations are also used for processing "Revus" , "Ridomil Gold" , they have a long period of protection, so you need to pay attention to the waiting time before picking greens.

Fusarium and tracheomycosis wilt

Cucumbers infected with Fusarium are easy to distinguish from healthy ones. In the heat, their leaves hang with “rags”. At the initial stages of the disease, after watering, the leaf turgor is restored, but with the further development of the disease, the vessels of the plant fail more and more, and water ceases to flow into the shoots and leaves. Leaves on cucumbers turn yellow and curl. Fusarium and other types of tracheomycosis wilt often appear in greenhouses, since eggplants, peppers, and tomatoes are also susceptible to this disease.

Fusarium wilt cannot be cured. by the time it is diagnosed by its withering leaves, the plant's vascular system is almost destroyed.

To prevent crop loss due to Fusarium, timely prevention is needed.

The causative agent of Fusarium must be destroyed in the soil even before cucumbers are planted in it. If fusariosis was noticed in the greenhouse last year, serious measures are needed, such as soil treatment with a potent fungicide, for example, "Maxim" .

For the prevention of Fusarium, antibiotics of bacterial origin are used, such as "Fitolavin" , or preparations based on hay bacillus, for example, "Bacterra" or "Fitosporin" . For the effectiveness of the use of biological products, they must be applied to the soil once every two weeks. It is necessary to maintain regular moistening of the earth and not allow it to dry out; for this, the beds are mulched. When the soil dries out and overheats, the beneficial microflora dies or becomes inactive.

Pests

Cucumbers have several dangerous enemies, they all settle on cucumber leaves, feed on their juices, which gradually leads to the fact that cucumber leaves turn yellow and curl. Insects are highly prolific, so if you do not notice their invasion in time, it will be difficult to cope with the problem.

Spider mite

The spider mite loves to settle on the leaves of cucumber and eggplant. Tiny insects are not visible to the naked eye, they can only be seen with a magnifying glass. You can find out about the presence of a spider mite by multiple small punctures on cucumber leaves. As the juices are sucked out of the leaves, they lose their vitality, turn yellow-brown, the edges of the leaf curl up.

Spider mite on cucumbers in a greenhouse

The spider mite is very prolific and reproduces at an incredible rate. A new generation hatches every 10 days. Since acaricidal preparations act only on adults, one treatment is not enough, several successive treatments must be carried out in order to destroy all insects.

Spider mites love dry air and high temperatures. When growing cucumbers in a greenhouse, the development of the mite can be significantly slowed down if the air humidity is increased by sprinkling on the leaves and soil in the evening.

To combat the tick, insect-acaricidal preparations, chemical or biological, are used. Before the start of fruiting, cucumbers can be shed with Aktara , it has a long period of protective action, while the toxic substance does not accumulate in the fruits. During the fruiting period, it is better to apply treatment with biological products with a minimum waiting period, such as "Fitoverm" .

Whitefly

The whitefly is often planted in greenhouses. Tiny white flies hide on the underside of the leaves and take to the air in a cloud when they are disturbed. Insects spread quickly, winter well, so if they once appeared, it is quite difficult to clean the greenhouse from them. Whitefly larvae suck the juice from the leaves, leaving a sticky secretion.

Yellow sticky trap for whiteflies and other flying pests

You can notice the presence of insects by numerous white spots on the upper side of the leaves. Larvae and adults are very small, but they can be seen.

To kill adults, yellow glue traps are hung in the greenhouse. Careful treatment of the lower leaves with Fitoverm and Biokill significantly reduces the number of whiteflies, for the complete destruction of insects it is necessary to carry out 2-3 treatments with an interval of 10 days.

"BioKill" can be applied even 3 days before harvest

Melon aphid

The gourd aphid can be found on all plants of the gourd family. It is not difficult to notice it, every summer resident is familiar with aphids, whether it is green, brown or black is not so important. Aphids are carried by ants to plants, so it is important to ensure that an elemental anthill does not appear next to the cucumbers.

Any chemical insecticide, such as "Kortlis" , however, they have a rather long waiting period. To destroy melon aphids on cucumbers, it is better to use the same Fitoverm or Biokill preparations, they are of biological origin, the waiting period before picking the fruit is 3 days.

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