Yellow spots on the leaves of cucumbers - the result of improper care or violation of the rules of cultivation. Much less often, this symptom indicates diseases or pests. It is not difficult to understand the reason, it is necessary to clearly understand when exactly the leaves began to turn yellow, and what factors could serve as a source of this phenomenon.
The influence of external conditions
Violation of vegetative development can occur due to: low light, sunburn, a small amount of water or nutrients, a sharp change in temperature, too rapid cooling of air and soil, infection by diseases or damage to all kinds of insects.
Yellow spots have their own characteristics. To determine the exact cause of their occurrence, it is necessary to carefully examine the stain, the damage differs:
- edging spots;
- additional symptoms of plant ailment.
Based on the signs of yellowing, it is necessary to choose the right measures to eliminate them, in different cases they will differ.
Cucumbers react very quickly to changes in air temperature, if on the eve it quickly dropped or heavy rain fell, then yellow bushes will appear on the bushes. The reason is that during a decrease in temperature, plants do not absorb nutrients, so vegetation is poor.
Normalization of temperature will lead to the return of a healthy color of cucumber leaves. Pay attention to weather forecasts, if there are signs of frost or rain, then cover the plants with a non-woven fabric, it passes air and does not allow the bushes to freeze.
Lack of light
Lack of sunlight occurs at different periods of cultural development. Often, it is observed at the time of growing sprouts and directly during fruiting.
If the leaves began to turn yellow during seedling cultivation, the reason is an unsuccessful location or cloudy weather. Photosynthesis slows down, and cucumbers cease to receive a sufficient amount of useful components. The problem is solved very easily - transfer the seedlings to a bright place or use phytolamps as a light source.
Having grown enough green mass, the plants begin to shade, so the leaves located below the stem do not receive the normal amount of light and turn yellow. This process is inevitable, in this case, you can simply cut off the yellow parts of the cucumber and cut the lashes that do not bring the crop. Such an event will help to partially increase the growing season.
If the plants appeared yellow damage with a clear edging, and before that you carried out watering on a sunny day, then the cause is a burn. The phenomenon of harm will not bring, but you must remember that watering should be carried out in the morning or in the evening.
It is impossible to water cucumbers under scorching sunshine.
Features of agricultural technology
Agrotechnics is a system of measures aimed at obtaining a high harvest. Sometimes non-compliance with at least one item leads to the appearance of yellow damage on the bushes.
Lack of pollination
The main reason for yellowness is the insufficient pollination of already flowering cucumbers. This may be due to the fact that only self-pollinated bushes have been planted. Due to the absence of insects, pollination of bushes does not occur.
In this case, use the “Bud” or “Ovary” means. There is also a folk remedy for attracting insects and restoring pollination: spraying with special “tasty” water (1 tbsp. Sugar or honey in 2 liters of water). Next year, do not make such a mistake and plant seedlings next to cucumbers that attract insects.
On 1 bush, leave no more than 25 ovaries. The reason for this is too fast bush development, the ovaries are rapidly gaining mass and growth. Many hybrids of cucumbers are capable of forming about 150 ovaries on 1 bush, but they will all be small and twisted.
It is necessary to timely pinch the shoots to provide them with a chance to fully ripen. Otherwise, extra shoots and ovaries lead to deformation of the fruit and the appearance of yellow damage.
Cucumbers are a moisture-loving culture. The reason for their yellowing and drying out is a lack of moisture and excessive scorching sun. On plants, the tips dry first, and then the entire leaf. To solve the problem, it is necessary to adjust competent and regular watering.
Spraying plants also benefits, but remember that excessively large amounts of water adversely affect the development of the bushes.
Read the rules and methods for watering cucumbers in the next article .
Moles, mice, shrews and other pests can damage the root system not only of cucumbers, but also of other crops growing in your area. Do not forget about the proper loosening of the soil, do not deepen too much, otherwise you yourself will damage the root system of plants.
Microclimate disturbance in the root of the culture is the source of the appearance of yellow spots on plants.
Yellowing of foliage in adult plants is normal, there is no point in fighting this. The bushes have already fulfilled all their destinations, now they are drying out, and they should be removed from the site.
Lack of fertilizer
A small amount of nutrient components in the soil can cause yellowing of the foliage of the plants. Often this culture thus shows a lack of nitrogen. Lack of fertilizer begins with the fact that the leaves become lighter, and then become yellow. As a result of a lack of nutrients, all the lashes on the cucumbers turn yellow, the fruits grow in the form of hooks.
Lack of nitrogen causes a large amount of wood ash, potash top dressing in the soil. To avoid this, you need to seedlings of this culture a couple of days before transplanting into open soil to feed with nitrogen fertilizers. During digging in spring and autumn, rotted manure is brought into the ground (1-2 buckets per 1 sq. M). Thus, there will be no shortage of nitrogen.
If during the transplantation of sprouts no useful substances were introduced into the soil, then during the growing season, feed the culture with chicken droppings or mullein. Also use an infusion called "herbal tea."
You can save the culture by applying mineral fertilizers, which contain nitrogen. Also, the leaves may turn yellow due to the huge amount of mineral fertilizing. Before putting them into the ground - read the instructions carefully. About how to properly feed cucumbers in the open ground, read the next article .
You will learn about the reasons for the appearance of yellowed leaves on cucumbers from the following video:
Diseases and Pests
In addition to agricultural errors, yellow spots can also appear due to diseases and pests. With them you need to be as careful and attentive as possible so that you can detect the ailment in time and rid the plants of it.
Symptoms: the sprouts sprout safely and develop quickly, but during the formation of the ovaries, first the leaves of the bushes acquire a yellow tint, and then they completely dry out. The fungus, penetrating the inside of cucumbers, releases toxic substances that stop the flow of micronutrients to the leaves.
Control options: change of cucumber varieties in the greenhouse, partial replacement of “sick” land.
Powdery mildew is one of the most dangerous fungal diseases of the culture. The disease does not allow photosynthesis to develop normally. First, small spots of light color form on the bushes, which eventually spread throughout the plant.
A white or yellow coating forms, then the plants dry.
Preventive measures against powdery mildew: stop the choice on varieties resistant to this disease, treat the soil with potassium permanganate, plant green manure.
Powdery mildew is not very different from powdery mildew. The first time the lesions appear on the lower side of the sheet, and then go to the upper part and become black. However, the first signs are unchanged - the formation of yellow or white spots on the foliage limited by veins. If nothing is done with the disease, then after a couple of days the plants will die.
The reasons for the appearance of downy mildew are: sudden changes in temperature, the presence of root rot, watering plants with cold and not standing water. First, weak plants fall under the influence of this disease, and then strong ones are affected.
Methods of struggle: treat 2 times per season the root parts of the culture with Previkur.
Yellowing of the leaves of the plant may be the result of root rot. The disease destroys the roots of cucumbers, from a lack of nutrients they begin to die. The reason is almost always the same - too much water.
If the bushes have already begun to fade, then the seedlings were improperly planted and improperly taken care of. Use a garden stick and move the soil from the stems of the bush. Just be extremely careful, you cannot damage the root system.
For treatment, treat the bush with a mixture: water 1 l + copper sulfate 2 tsp. + wood ash 6 tbsp. l You can use chalk or activated carbon. If these actions did not help to save the bush, then dig it and burn it. Pour copper sulfate solution into the depression where it grew.
The most dangerous pests for cucumbers are spider mites and gourds. The second insect populates the lower part of the leaf of the culture and drinks the juice of the bush, aphids can be destroyed only by spraying and airing the greenhouse in a timely manner.
A spider mite is easy to recognize, it creates small cobwebs on the back of the leaf. Spots of a characteristic shade appear on the bushes, then they completely turn yellow and dry. The tick brings tremendous harm, they fight with such substances: “Akarin” and “Fitoverm”.
How to process cucumbers so that the leaves do not turn yellow?
Yellowing of leaves of this culture can be avoided, it is only necessary to adhere to certain preventive recommendations:
- When planting seedlings in open soil, keep a distance between plants (0.2-0.3 m).
- Make good lighting, plant cucumbers in a sunny area.
- Do not overfill and dry the bushes.
- Ventilate the greenhouse, but do not drafts.
- Regularly feed the cucumbers you need.
- Loosen the soil so that the root system has time to be saturated with oxygen.
- Control the number of ovaries on one plant, take the crop on time.
So that the leaves do not turn yellow, treat the plantation with solutions that are safe for people, but effective for various diseases. Some of them:
- Milk and soap. Pour 1 liter of milk into a 10 liter bucket. Dip 20 g of grated soap and 25 drops of iodine. Fill the mixture with warm water. Stir until the soap has completely dissolved. Use this tool as soon as the plant releases 4 true leaves.
- Iodine and brown bread. Pour 1 loaf of bread with 10 liters of water. Once it is completely swollen, add 1 jar of iodine to the mixture. Use this product only in diluted form (1 liter of substance per 10 liters of water). Treat the bushes once every 2 weeks.
- Husk from onions. Take a 0.5 L jar of husk, pour 10 L of water, bring the product to a boil and leave it overnight. Dilute 2.5 l of the product with 10 l of water and use for processing bushes.
- Potassium permanganate. As soon as you notice yellowing on the leaves - immediately use a solution of potassium permanganate (1%). It will disinfect and rid the bushes of fungal spores.
For how a solution of brilliant green from yellowing leaves will help, see the following video:
Features of the fight against yellowing leaves on cucumbers
Depending on the place of cultivation of cucumbers, the rules for caring for them also differ. In violation of agricultural technology, yellowing of plant foliage may begin.
In the greenhouse
The main reasons for the appearance of yellow spots on the bushes are non-compliance with agricultural standards of cultivation. Basic rules for the care of cucumbers in a greenhouse:
- Follow watering rules. When the plants begin to bloom and bear fruit, apply water 3 times a week. For 1 square. 10 liters of water is enough. On hot days, increase the amount of water.
- Stick to one temperature regime. Stress after a sharp change in temperature does not need the plant. From time to time, air in the greenhouse, so you will attract insects to fertilize the bushes, and destroy all spores of fungi.
- Feed your plants regularly. Lack of nutrients leads to yellowing of cucumber leaves.
- Follow the correct landing pattern. Do not allow thickening of the beds, otherwise excess crowding will lead to yellowing of the lower sheets.
In the open ground
The main rules for the care of cucumbers in the open ground:
- Cover plants in a timely manner. Do not leave the plantations without shelter, especially if the temperature has dropped to +15 degrees. Use agrofibre or polyethylene film arcs. On sunny days, remove the covering material.
- Do moderate watering. When the leaves begin to dry from a lack of water - bring it in more than before. If the reason is an excess of water, then stop watering the bushes.
- Loosen the soil in time so that the root system is fully saturated with oxygen. You can add wood ash or sand to the ground at this point.
- Treat bushes from pests. In the open field, “catching” the disease is much easier than in the greenhouse, so check the plantings three times a week. Control the amount of fertilizing.
- Do not fertilize if plants do not need them. It is better to immediately feed the soil during planting seedlings.
On the balcony
Growing cucumbers on the balcony is a very difficult task. Why the leaves of cucumbers on the balcony turn yellow:
- Too small containers for growing this crop. Young plants begin to turn yellow if their root system is too crowded. Transplant the plants into other pots and then the green shade of the leaves will be restored.
- High humidity. Fungal diseases begin to attack in a too humid environment. Ventilate the balcony or loggia regularly.
- Large or small amount of water. Watch the watering, based on the size of the bush and humidity in the room.
- Not enough fertilizer. A plant from a small pot gradually draws out all the useful trace elements, so they need to be added to the soil all the time. The first top dressing is introduced after 2 leaves have appeared on the sprouts. You can use the finished mixture or make it yourself: 5 l of water + 5 g of ammonium nitrate + 5 g of potassium salt + 5 g of superphosphate.
Yellowing leaves of cucumbers is the result of improper care for them. Follow the basic rules of agricultural technology, and you will significantly reduce the risk of yellowness on plants.