12 Reasons Causing Plant Leaves Turn Yellow
When you see the leaves turning yellow, it's time to put on your Sherlock Holmes hat and do a little sleuthing to find possible causes and solutions. Environmental conditions, cultural causes, pests or diseases, or even the medium in which the plant is grown are among the reasons why the leaves turn yellow.
1. Premature Aging
It is mainly caused by the aging of the roots of the crop, reduced uptake of water and fertilizer, lack of nutrient supply at the early stage, and lack of water and fertilizer supply at the late stage.
Poor growth vigor, yellow leaves.
Use organic fertilizer, microbial fertilizer, biological organic fertilizer to enhance root growth and absorption activity.
Use high nitrogen and potassium fertilizer to enhance growth vigor and green leaves.
Use urea, potassium dihydrogen phosphate, brassinolide, amino acid, magnesium/iron containing foliar fertilizer, etc., for quickly foliar nutrition supplement, enhance leaf photosynthetic capacity, and extend the life of green leaves.
Use functional fertilizers such as amino acid, mineral source potassium fulvic acid and chitin to enhance root growth activity and nutrient absorption capacity.
Overwatering can waterlog the soil. Without oxygen, roots start to die, and the plant starts yellowing.
Yellow, drooping, and dull, lifeless leaves
Loose soil and drain in time to control the amount of irrigation.
Foliar spraying urea, potassium dihydrogen phosphate, brassinolide and compound sodium nitrophenolate.
Properly supplement with micro-fertilizers containing boron, calcium, and silicon to promote root growth.
Use amino acid, chitin, etc., to promote roots, and use fungicide to prevent disease and rot.
It is mainly caused by a lack of water for a long period during the growing season of the crop.
Yellow, dry, and curling leaves
Frequent watering to keep the soil moist.
Foliar spraying potassium dihydrogen phosphate, brassinolide, amino acid, and etc.
4. Nutrient Deficiency
It is mainly caused by the lack of iron, potassium, nitrogen, magnesium, calcium, and other nutrients during crop growth.
Iron deficiency – This causes yellowing, stunted growth and interveinal chlorosis. You will see it normally in new growth first. Test your soil and maintain a pH below 7.
Potassium deficiency – The leaves, especially older leaves, may have brown spots, yellow edges, yellow veins or brown veins.
Nitrogen deficiency – This causes stunted growth and yellow edges on the tips of the leaves. The veins may be yellow, and sometimes the whole leaf will be pale yellow.
Magnesium deficiency – This causes yellowing of the leaves between the veins with the veins remaining green and usually appears on lower leaves first.
Calcium deficiency – This will cause crinkled, mottled or distorted leaves and will not allow the tips of the leaves to grow.
Depending on the type of crop nutrient deficiency, use a foliar fertilizer containing iron, potassium, nitrogen, magnesium, calcium, sprayed 2-3 times, such as urea, calcium nitrate, chelated magnesium, chelated iron, chelated calcium, etc.
5. Light Deficiency
It is mainly caused by the lack of light and weak light in the process of crop growth for a long time and the failure to synthesize sufficient chlorophyll (or a large amount of chlorophyll decomposition in leaves) through photosynthesis.
The leaves look droopy and faded and easy to dropping early.
Increase the time and amount of light for crops.
Improve light by pruning, branching, thinning leaves, etc.
6. High Temperature and Excessive Light
It is mainly caused by the continuous high temperature and intense light irradiation of the weather, as long periods of high temperature and intense light will cause large amounts of leaf water to evaporate rapidly.
Withered, yellow leaves, easy to dropping early. Young leaves and fruit are prone to scorch spots.
In cases of high temperatures and strong light, take care to add shade to cool down or sprinkle straw on the ground to avoid direct sunlight and cool down.
Spray water on stems and leaves in the morning and evening to increase humidity and reduce high temperature hazards.
Use potassium dihydrogen phosphate + brassinolide to enhance crop resistance to high temperatures and strong light, and foliar spraying amino acids or new high-lipid films to reduce evaporation from leaves.
7. Low Temperature
It is usually caused by a sudden strong cooling of more than 10 degrees or a long period of cold conditions below 0 degrees, mainly in early spring or winter.
Poor growth vigor, withered and yellow leaves.
Use organic fertilizer, cultivate loose soil in advance, root mulch, field irrigation, temporary warming (such as smoking and cold driving, setting warming equipment, etc.), covering manure and straw, spraying antifreeze or potassium dihydrogen phosphate + brassinolide and so on to avoid or reduce the low temperature freezing damage on crops.
Yellow leaves are mainly caused by diseases on crops (especially leaves), the main types of diseases are fungal diseases, bacterial diseases and viral diseases.
Fungal diseases: Diseases with white, black, red, yellow, pink, orange, brown and other colorful appearances.
Bacterial diseases: Fluffy bacteria pus/liquid, water immersion/oil immersion disease spots and soft rot, etc.
Viral diseases:Leaf deformity, curling, yellowish-green disease spots, yellow leaves, etc.
According to the type of disease, spraying the fungicides.
Usually, you will be able to easily tell if pests are the reason your plant’s leaves turn yellow! The most common pests are aphids, whiteflies, scaly bugs, spider mites, thrips, etc.
The yellow spots on plant leaves will often surround bite marks or ‘bullet’ marks (indented, ringed spots, similar to bullet holes).
According to the type of pests, spraying the insecticides.
10. Pesticide Phytotoxicity
It is mainly caused by improper use of pesticides, such as pesticide drift, excessive dosage or high concentration, application at crop growth sensitive period, etc.
Yellow leaves, disease spots or leaf deformity, sudden slow growth of crops, a large number of fallen flowers, fruits and leaves, etc.
Large amounts of irrigation water in the field.
Repeated washing of the leaves with clean water.
Use urea, potassium dihydrogen phosphate, brassinolide, GA3, etc. to reduce drug damage and promote recovery.
11. Fertilizer Phytotoxicity
It is mainly caused by over-fertilization, use insufficiently fermented manure, and ammonia poisoning after fertilization in poorly ventilated greenhouses, etc.
Burning roots, seedlings, leaves.
Large amounts of irrigation water in the field.
Spray urea + potassium dihydrogen phosphate + brassinolide to accelerate growth and reduce the fertilizer damage.
Use root function fertilizers to stimulate rapid growth of new roots.
For ammonia poisoning of crops in greenhouses, enhance ventilation.
For foliar damage, Repeated washing of the leaves with clean water.
12. Acid-Base Imbalance
The main reason is that the acidity and alkalinity of the soil is not suitable for crop growth, as some crops grow in alkaline soils and others in acidic soils.
Moss or salinization of the soil, yellow leaves
Apply the fertilizer that is opposite to the acid and alkalinity of the soil.
Application high-quality organic manure, farm manure, microbial manure, green manure, etc.
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