What is the reason for the yellowing of the leaves of cucumber seedlings

There are several reasons for the yellowing of cucumber leaves:One is to water it too much, the root system will rot due to lack of oxygen in the soil, and yellow leaves will appear.

The second is to apply too much fertilizer to it, and if there is excess nutrition, it will also cause the leaves to turn yellow.

The third is to be directly exposed to the sun by the intensity of summer.

Fourth, there is a lack of trace elements.

Reasons for yellowing of cucumber seedling leaves:

1. Watering discomfort.

Reason: Cucumbers have a high demand for water during the seedling period, and if the substrate is dry for a long time, the seedlings will soon wilt and turn yellow. In addition, the ability of seedlings to tolerate water and moisture is relatively poor, and if the soil is in a state of stagnant water for a long time, it will cause its roots to be unable to breathe, resulting in yellow water.

Solution: If it is caused by excessive drought, it is enough to water it in time, and keep the substrate in a slightly moist state, which is most conducive to its growth. If it is caused by overwatering, such as rainwater accumulation, it needs to be drained in time, and proper loosening of the soil ensures that the root system has good air permeability.

2. Improper lighting.

Reason: The stress resistance of cucumber seedlings is relatively poor, if the growth environment is exposed to strong light for a long time, it is easy to sunburn its seedlings, resulting in yellowing. If it is too shaded, it will also affect the normal growth of the seedlings, and they will not be able to carry out sufficient photosynthesis, resulting in yellowing.

Solution: If it is caused by too strong light, it needs to be shaded in time, and black gauze can block part of the sunlight for it and relieve the growth pressure of seedlings. If it is caused by poor lighting conditions in the growth environment, it needs to be transferred to a good lighting location in time to strengthen the daily light time, and the seedlings will recover soon.

3. Lack of nutrients.

Reason: cucumber seedlings in the growth period of the nutrient demand is still relatively large, if the substrate is poor, the nutrient content is relatively small, the seedlings can not absorb enough nutrients, the growth is getting weaker and weaker, there will be yellowing.

Solution: It needs to be applied top dressing in time, you can spray the foliage of the seedling with potassium dihydrogen phosphate, or apply it fully decomposed farmhouse fertilizer water.

Fourth, too much fertilization.

Reason: cucumber seedlings have poor tolerance to fertilizer, if the one-time fertilization is too much or the concentration is too large, it will lead to fertilizer damage to cucumber seedlings, resulting in dry yellow leaves, zooming.

Solution: It needs to be watered in time, so as to dilute the concentration of fertilizer in the soil, if it is a potted plant, it is best to replace it with new potting soil in time to avoid it from continuing to suffer from fertilizer.

The possible reasons for the yellowing of cucumber seedling leaves are as follows:

1. Downy mildew.

The leaves of cucumbers are yellow, and some of the leaves wilt may be downy mildew, and the temperature is between 16 and 22 degrees, and cucumbers are prone to downy mildew in poor growth. Cucumbers have downy mildew, and after cutting off the diseased leaves and burning them, they can be controlled with chemicals such as mancozeb, prick, anker, enoylmanganese zinc and gold redomir.

2. Viral diseases.

If the cucumber leaves are yellow and some of the leaves are wilted during the seedling period, it may be a viral disease. Viral diseases can cause the leaves of cucumber seedlings to turn yellow, dry and curly. If the cucumber has a viral disease, the diseased leaves should be cut off first, and then the cucumber should be sprayed with poison buster, which can be sprayed once in 7 10 days, and the disease can be relieved after spraying 3 or 4 times.

3. Bacterial keratopatch.

During the seedling period, cucumber has bacterial horn spot disease, yellow-brown lesions appear on the leaves, and the leaves will gradually dry up in the later stage. If the cucumber has bacterial horn spot disease, cut off the diseased leaves and branches and burn them intensively, spray the cucumber with copper succinate or Garry pesticide agent, and use a variety of agents alternately, and the effect is better.

Fourth, whitefly.

Whitefly is a common insect pest of cucumbers, which will attach to the young leaves of cucumbers and suck up nutrients and water from the leaves, which will make the leaves yellow and dry. If there are whiteflies on the branches and leaves of cucumbers, the branches and leaves should be cut off and burned in time, and the cucumbers can be sprayed with chemicals such as thiazinone, fenvalerate or deltamethrin for insect control.

The second possible cause of cucumber yellow leaves is the common disease of melons caused by bacterial infection, which is called macular disease. This disease is caused by a fungal infection buried in the ground, and it is also the deadliest disease of melons. If it is found that the growing melons have a yellow spot disease, they can only be temporarily maintained with drugs, and after the end of the season, the land where the melons have been planted will be thoroughly disinfected, and then the land where the melons have been planted can be cultivated in rotation, and the original melon plots will be desertified, and then replanted after two or three years.

Only in this way can we effectively control the occurrence of cucumber yellow spot disease!

Ensure that the base fertilizer is sufficient, and the urea aqueous solution can be sprayed on the foliar surface. Through the method of extra-root topdressing, the lack of nitrogen can be quickly supplemented. The earlier it is found that the leaves turn yellow, the more timely supplementation is conducive to improving the yield of cucumbers.

Watering too much can lead to the appearance of stagnant water, which will cause its fundamental respiration to weaken, affect photosynthesis, and the cucumber will appear yellow leaves. Treatment: You can pause the watering and let the water dry, and it will get better after a period of time.

Rotting disease mainly damages its stems and vines, and eventually the entire vine will rot, resulting in the cessation of nutrient transport and the serious impact on the growth of the fruit, which is most serious in the first half of the year.

Prevention method: rot disease is caused by too high temperature in the planting environment, it may also be that it grows too fast, causing it to crack, after finding the cracking, we must disinfect it in time, which can effectively prevent the occurrence of rot disease. Cucumber root nematode mainly harms the roots, can not absorb water and fertilizer, the wound formed by the root nematode damage, will make other bacteria invade, the aboveground part of the cucumber damaged by the root nematode appears yellow leaves, plant dwarf and other phenomena.

Use the lineicide granule furrow, hole or whole field application to provide a good growth environment for crops; If nematodes appear in the growth period, irrigate the roots with aqueous nematodes and flush them, and if they are used together with water-soluble fertilizer, the effect is better.

It may be that the cucumber seedlings are short of water, or it may be that there are insects in the roots of the cucumber seedlings, so they will turn yellow.

The yellowing of cucumber seedlings may be due to nutritional deficiencies and need to be replenished, because malnutrition of the plant will lead to insufficient nutrients transported to the leaves, resulting in yellowing of the leaves.

It is because the cucumber seedlings cannot fully react to light because they do not receive sufficient light, so they will turn yellow.

Excessive fertilization: Although cucumber planting has a lot of nutrient demand, it is not possible to arbitrarily increase the amount of fertilizer, too much nutrients will cause excess nutrients in cucumber plants and cause yellow leaves.

The leaves of cucumber seedlings are yellow, due to changes in the external environment, too much watering, too much fertilization, and cucumber deficiency.

1. Changes in the external environment.

Sudden changes in temperature, humidity and light can cause cucumber leaves to turn yellow. Cucumber is a typical thermophilic plant, with a fertility temperature of 10 32. The suitable temperature is higher during the day, about 25 32, and the lower temperature at night, about 15 18.

The appropriate temperature for photosynthesis is 25 32 and should be adjusted according to these temperatures.

2. Overwatering.

Yellowing of cucumber leaves due to excessive moisture: The leaves of the plant are generally yellow, especially the top leaves are small, and the growth is slow, and wilting occurs in severe cases. The suitable soil relative humidity is 85% 90%, cucumber has a strong adaptability to air humidity, and the relative humidity of the air at night can reach 90% 100% can also be tolerated, but the humidity is too high and prone to disease, so it is not possible to water cucumber seedlings many times, so as to prevent the root system from being too much water and lack of oxygen and rotting the root system to prevent the root system from growing normally.

3. Excessive fertilization.

Although cucumber planting has a lot of nutrient demand, it is not possible to arbitrarily increase the amount of fertilizer, too much nutrients will cause excess nutrients in cucumber plants, resulting in yellow leaves. Cucumber fertilization should be carried out according to different growth stages, such as seedling fertilizer such as 20-10-20+te at the seedling stage, and balanced and high potassium fertilizer in the middle and late stages.

4. Cucumber is deficient.

Cucumber demand for trace elements is also a lot such as magnesium, boron, iron, zinc, calcium, etc., if a large shortage of these elements will reduce the quality of cucumber plants, fruits, etc., for this in the middle and late stage of the topdressing process should also take into account the addition of trace elements.

The environment in which cucumbers are grown

1. Temperature. Cucumbers prefer warmth and are not tolerant of cold. The fertility temperature is 10 32.

Generally, 25 32 during the day and 15 18 at night grow best; The most suitable ground temperature is 20 25, and the lowest is about 15. The optimal temperature difference between day and night is 10 15. Cucumber high temperature 35 poor photosynthesis, 45 high temperature obstacles, low temperature -2 0 freeze to death, if the low tree bush warm refining seedlings can withstand 3 low temperature.

2. Illumination. The North China variety has not strict requirements for the length of the sunshine wheel, and has become a sunshine neutral plant, with a light saturation point of 10,000 lux and a light compensation point of 1500 lux, and most varieties grow well under the condition of 8 11 hours of short sunshine.

3. Moisture. Cucumbers have a high yield and a large water requirement. The suitable soil moisture is 60% 90%, the water at the seedling stage should not be too much, the soil moisture is 60% 70%, and sufficient water must be supplied during the fruiting period, and the soil moisture is 80% 90%.

The suitable air relative humidity of cucumber is 60% to 90%, and excessive air relative humidity is easy to develop diseases and reduce yield.

The reasons for the yellow leaves of cucumber seedlings are: environmental changes, excessive watering, and improper fertilization.

1. Environmental changes.

Cucumber seedlings grow in the environment of temperature, humidity and light changes will cause the leaves to turn yellow, the plant likes warm, humid climate, the suitable temperature for growth is between 10-32 degrees, pay attention to the management of water and light during the maintenance period.

2. Overwatering.

When watering cucumber seedlings too much, it will lead to water accumulation in the root system and can not breathe normally, which will affect the growth and development of leaves, and the soil moisture can be kept at 85-90% during the maintenance period to avoid blind irrigation and rooting.

3. Improper fertilization.

The fertilizer concentration applied during the growth of cucumber seedlings is too large or too high, which will cause excess nutrients and yellowing of leaves, and potassium fertilizer can be applied every 10-15 days at the seedling stage.

How to grow cucumber seedlings

1. Soil preparation and fertilization.

Cucumbers are suitable for growing in loose and breathable, nutrient-rich soil, planting to choose an open, sunny and ventilated field, and use a hoe to dry the field deeply, eliminate weeds and bacteria, but also mix farm fertilizer into the soil to provide a fertile growth environment for cucumbers.

2. Select seedlings.

Before planting cucumber seedlings, cucumber seedlings with a seedling age of more than 35 days, robust growth, thick leaves and intact cotyledons should be selected from the seedlings, and then the roots that are too dense and weak will be cut off with sterilized scissors, so that the plants can better adapt to the environment.

3. Planting.

When planting cucumber seedlings, dig a soil ditch with a distance of 40 centimeters and a depth of 5 centimeters in the soil, and then place the selected cucumber seedlings in the ditch according to the plant spacing of 20 centimeters, and then cover a layer of fine soil that can be changed, and after planting, the cucumber seedlings should be watered and moistened with all the soil.

<> cucumber seedlings have yellow leaves, which may be caused by improper hydration during the maintenance process, and it is necessary to water the cucumber in time, or it may be that the cucumber seedlings do not have sufficient light in the process of growth, and need to supplement the light, or it may be that the cucumber seedlings suffer from diseases, and the plants need to be sprayed with sterilizer immediately, so that the yellow or silver melon seedlings can resume growth.

1. Strict water control.

Watering too much or too little when maintaining cucumber seedlings will lead to yellowing of cucumber seedling leaves, so it is necessary to provide water for the plant correctly when maintaining cucumber seedlings, replenish water in time when there is a lack of water, and strengthen ventilation and dehumidification when there is too much water.

2. Supplemental lighting.

Cucumber seedlings leaf yellowing may also be a light problem, cucumber seedlings in the process of growth can not do without light, insufficient light or excessive light will make the plant can not carry out normal photosynthesis, resulting in yellowing leaves, so in the maintenance of cucumber seedlings need to provide sufficient light, in the light is too strong to shade it, to avoid sunburn.

3. Reasonable fertilization.

The yellowing of the leaves of cucumber seedlings may also be due to the fact that the nutrients provided to the plant during maintenance are too simple or too much fertilizer is applied. Therefore, the fertilization of cucumber seedlings should be adjusted according to their growth stage, and the variety of fertilizer should be adjusted to provide them with balanced nutrients for slag, so as to improve the quality of cucumber plants.

4. Disease prevention and control.

Cucumber seedlings are affected by pests and diseases in the process of growth, which will also lead to the phenomenon of yellowing of leaves.