Magnesium deficiency
Magnesium deficiency in plants is characterized by yellowing leaves, particularly between the veins, while the veins themselves remain green. This occurs because magnesium is a vital component of chlorophyll, and its deficiency disrupts photosynthesis.
What you see
Magnesium deficiency is a common nutritional issue in plants where the older leaves exhibit interveinal chlorosis, meaning the areas between the veins turn yellow while the veins remain green. This is because magnesium is a crucial part of chlorophyll, the pigment responsible for photosynthesis. Without adequate magnesium, plants cannot efficiently produce energy, leading to reduced growth and vitality. Unlike diseases caused by pathogens, magnesium deficiency does not involve any infectious agents and can be corrected by adjusting the plant's nutrient intake. It is important to differentiate this deficiency from other nutrient issues by observing the specific pattern of yellowing and considering the plant's overall nutrient regimen.
Symptoms
- Yellowing between leaf veins
- Green veins on yellow leaves
- Older leaves affected first
- Leaf drop in severe cases
- Stunted growth
Why it happens
The underlying cause is a lack of magnesium in the soil, which is essential for chlorophyll production and photosynthesis.
Conditions that favour it
- Sandy or acidic soils
- Excessive rainfall or irrigation
- High potassium levels in soil
- Low soil organic matter
- Poor soil fertility
Plants most affected
- Tomato
- Pepper
- Rose
- Azalea
- Rhododendron
- Citrus
- Grapevine
- Apple
- Potato
- Cucumber
How to correct it
Educational information only, and not a substitute for professional diagnosis. Identify the problem before treating it, and check that any product is registered for this plant and this use where you live.
Cultural control
- Improve soil drainage
- Ensure even watering
- Incorporate organic matter
- Rotate crops to maintain soil health
Organic options
- Epsom salt
- Dolomitic lime
Prevention
- Regular soil testing
- Balanced fertilization
- Use of magnesium-rich amendments
- Avoid over-irrigation
- Maintain proper soil pH