Leaf chlorosisis a physiological disease that causes the leaves to turn yellow as a result of disruption of photosynthesis and chlorophyll production. We explain what may besymptoms of leaf chlorosison various garden plants, how to determine the causes of this disease, as well as how tocontrol leaf chlorosisto prevent its formation in future. We also present photos that will help you identify the causes of leaf chlorosis!
Leaf chlorosis
Fig. pixabay.com
Leaf chlorosis - causes and symptoms
1. Chlorosis caused by too high pH of the soil
This type of leaf chlorosisoccurs most often in soils with a pH close to neutral (pH about 7.0). The higher the pH, the lower the availability of certain elements to plants: iron, magnesium, manganese, nickel, copper, boron and zinc. When the soil pH is too high, plants cannot take these nutrients from the ground, despite the presence of these nutrients in the soil.
The acidophilic species are particularly susceptible to chlorosis due to too high pH of the soil . Growing on too alkaline soil, these plants are unable to take up nutrients, despite their availability in the soil.
Plants are particularly sensitive:
- ornamental:hydrangea, rhododendron, heather and heather, genera, witch hazel, hibiscus, St. John's wort, roses, camellia, wisteria, magnolia, surfinia, gerbera,
- fruit:actinidia, blueberry, cherry, cherry and strawberries,
- vegetable:tomatoes, peppers, potatoes.
Good advice!It is not without reason that we start the article by describing chlorosis due to the wrong pH of the soil. Before looking for other causes of leaf chlorosis and supplementing minerals with fertilizers, measure the pH of the soil and determine if it is appropriate for the plants being grown.
If the soil pH is in line with the plant requirements,chlorosis may be caused by a nutrient deficiency in the soil . Most often we are dealing with a deficiency of iron, as well as magnesium, potassium and nitrogen.
2. Chlorosis due to a lack of iron (Fe)
Iron is one of the main elements necessary for photosynthesis. Therefore, its absence quickly leads to yellowing of the leaves and the formation of chlorosis.Lack of iron in the plant can be caused by :
- high soil pH above 6.5
- high levels of calcium or phosphorus, copper, manganese, magnesium or zinc, which impede iron absorption,
- soil is too compact.
Rose leaf chlorosis caused by iron deficiency
Fig. depositphotos.com
Symptoms of iron deficiency in the plant are :
- chlorosis, initially as lighter patches between the veins. With a very strong deficiency of elements, the leaves and the veins turn yellow and even turn white,
- leaf yellowing occurs mainly on young leaves,
- weakening of growth and flowering.
3. Chlorosis due to a lack of magnesium (Mg)
Magnesium is involved in photosynthesis and is one of the main building blocks of chlorophyll.Magnesium deficiency is usually caused by:
- excess potassium and calcium in the soil,
- rain or water too much.
Chlorosis of zucchini leaves caused by a lack of magnesium
Fig. depositphotos.com
Symptoms of a lack of magnesium in the plant are :
- chlorotic yellow spots form between the main veins of the leaves, which remain green,
- necrosis,
- leaves curve upwards along the main vein,
- the symptoms of magnesium deficiency initially appear on older leaves, but at a later stage they may also appear on younger leaves,
- yellowing and browning of the youngest growths of conifers (thuja, spruce and cypress are particularly sensitive to magnesium deficiency).
4. Chlorosis due to a lack of nitrogen
Nitrogen is an indispensable component of proteins in all plant tissues.Nitrogen deficiency is usually caused by :
- insufficient supply of plants with some micro- and macronutrients, such as: magnesium, potassium, sulfur, phosphorus, copper, molybdenum or manganese,
- low organic matter content in the soil,
- frequent and heavy rainfall or over-irrigation (nitrogen is easily washed away).
Chlorosis of grapevine leaves caused by lack of nitrogen
Fig. depositphotos.com
Symptoms of a lack of nitrogen in the plant are :
- fading, yellowing of the entire leaf blade, including the veins,
- in some species, the main nerves can turn red or reddish-violet,
- browning and drying of the leaves.
Nitrogen deficiency in grapevinesapart from the discoloration of the lamina yellow-green, it is characterized by a red discoloration of the petioles and the beginnings of the veins.Chlorotic changes initially affect older leaves, but with time the discoloration begins with those located higher. In the case ofcucumber chlorosis , the lower leaves lose their normal green color, which gradually changes from pale green to green-yellow, and finally to bright yellow.
5. Chlorosis due to a lack of potassium
Potassium plays an important role in the water management of plants and protein synthesis.Potassium deficiency is usually caused by :
- inappropriate soil reaction (too acidic and too alkaline soils hinder the absorption of potassium by plants),
- lack of water during the growing season.
Leaf chlorosis caused by nitrogen and potassium deficiency
Fig. depositphotos.com
Symptoms of a lack of potassium in the plant are :
- leaf blade yellowing starting at the edges and gradually moving deeper into the blade,
- drying of the altered tissue,
- reduced growth, dwarfism and poorer yielding of plants.
Leaf chlorosis - how to prevent
The best and long-lasting results incombating leaf chlorosisare obtained by improving the structure and chemical properties of the soil and proper plant care, i.e .:
- avoid planting acidophilic species on alkaline soils,
- appropriate plant irrigation and substrate drainage,
- fertilization with compost and soil mulching with pine or spruce needles or peat and conifer bark,
- loosening the soil to loosen it and aerate it,
- soil pH control and adjustment as needed,
- proper fertilization, in accordance with the recommendations for a given group of plants,
- if necessary, use foliar fertilizers containing ingredients missing from plants.
MSc Eng. Anna Błaszczak
