The first answer to the question: "why do cucumber leaves turn yellow?" there will be a lack of moisture. Everyone needs water and especially fruit plants, which, when there is a lack of water, begin to save it and for this they shed the leaves, and before the leaf falls, it turns yellow due to the fact that the plant begins to draw magnesium from the leaf and redirect it to the stem and roots.
- Many summer residents make mistakes when watering cucumbers.
- Why do the leaves turn yellow if watering is established?
- Cucumber protection
Many summer residents make mistakes when watering cucumbers.
- or watered often and little, believing that this way the plants get better moisture. But in fact, with low and frequent watering, moisture does not reach the roots in depth, but is distributed in the soil. The plant begins to adapt, and the roots rise higher, where, in strong sun, they overheat, and are also damaged when loosening;
- or watered a lot, but rarely. It turns out: the culture is flooded with water at some point, but during a hot summer, the water quickly leaves and, as a result, the honey agaric plant does not receive the necessary moisture or the roots begin to rot.
It is very important to correctly organize watering of cucumbers so that the fruits are undeformed and tasty, and the leaves are green. The norm for watering cucumbers is about 25 liters per plant with two watering a week.
You also need to test the soil for moisture, periodically take a piece of earth from a ten-centimeter depth and squeeze it in your hand, determining whether the soil is wet or not, in order to avoid overflow or underfilling.
Why do the leaves turn yellow if watering is established?
- the wrong area for cucumbers was selected. Cultures need to be alternated, and for cucumbers, the site should be such where the sun does not shine very much at the peak;
- moisture gets on the leaves and in strong sun the leaf gets burned, it is better to water it in the evening or early hours of the day;
- cucumbers suffer from elevated air temperatures (usually this is strongly manifested in greenhouses). A systematic air supply, regular ventilation is required;
- cucumbers lack mineral fertilizers. So, the lack of nitrogen will noticeably affect the development of the entire plant: the lashes will be thin, the foliage will first become light salad color, then turn yellow and fall off. Even yellow spots on the foliage of the cucumber may indicate a lack of calcium. The appearance of a yellow edging in the old lower leaves of cucumbers characterizes a magnesium deficiency. Conversely, if young cucumber leaves turn yellow, then this is a lack of copper. Dark green veins on cucumber leaves with yellow spots are characteristic signs of iron deficiency. Also, the lower leaves of cucumbers die off, the tips of the leaves turn yellow with a lack of zinc;
- the plant may have been attacked by parasites or disease. A frequent greenhouse guest for cucumbers is whiteflies, they suck juice from plants and the leaves turn yellow. Aphid colonies lead to yellow leaves, they are located below the leaves of cucumbers, as well as on young growths.
Of the diseases that cause yellowness of cucumber leaves, first of all, fungal diseases should be pointed out. They develop strongly when crop rotation is not followed. Fungi and pathogens accumulate in the soil.
The Fusarium fungus causes the roots of the cucumber to die off, which leads to yellow leaves, and then the plant withers. Affected specimens are easily pulled out of the ground. Often, the development of the disease is observed with sharp daily fluctuations in atmospheric temperature, but with stabilization of weather conditions, many weakly affected cucumbers can straighten out. Also, the cause of wilting of cucumbers can be pityosis. It is also a fungal parasite that causes cucumber root necrosis.
So, choosing the right planting site, timely deep watering of cucumbers and feeding them will largely ensure the good health of the plants. When applying fertilizers, be careful about the dosage.
To curb the development of fungal diseases, a crop rotation is necessary, in which pumpkin crops are planted on the previous beds no earlier than four seasons. In greenhouses, it is recommended to periodically replace the soil or carry out disinfection.
In addition, biological methods of soil disinfection are used, in which the soil is carefully removed from the greenhouse and placed outside in a stack no more than a meter high. Each layer is spilled by biologically active microorganisms (preparations "Baikal EM-1", humus tinctures, etc.), you can add compost. Such disinfection takes 2-3 years.
Remember that the spread of fungal diseases is promoted by mechanical damage to the roots and trunks of cucumbers. Since their roots are very susceptible to damage, it may be best to do without loosening the soil. In this case, pay more attention to preparing the soil before planting.
In addition to the alternation of vegetable crops, biofungicides containing trichodermine can be recommended for biological protection of cucumbers. It is necessary to introduce mycelium into each hole at a distance of 3-10 cm from the shoots. Trichodermine inhibits the development of pathogens and has a stimulating effect on the development of vegetable crops. Not phytotoxic, harmless to insects, humans and animals.
It is better to prevent yellow leaves by observing the growing conditions and providing cucumbers with the necessary nutrients. In addition, it is necessary to monitor the state of the microflora of greenhouses and the site, to prevent the development of pathogenic fungal diseases. Then you will always have healthy plants and a high yield of cucumbers.