How to recognise it
Leaves become pale, yellowed or with pink tints. In extreme cases the whole plant can become discoloured, growth is stunted and flowering/fruiting can be reduced.
Here is a quick guide to the types of nutrient deficiencies causing chlorosis and the key symptoms you can use to identify them:
- General paling of leaf colour, sometimes with yellow or pink tints, whole plant is yellowed and spindly – Nitrogen deficiency
- Foliage turns blue, yellow or purple with brown discolouration in blotches or on leaf tips/margins – some leaves may roll inwards – Potassium deficiency
- Dull, yellowed foliage and slow growth – Phosphate deficiency
- Yellowing or browning which starts at the leaf margins and extends between the leaf veins, affects youngest leaves first – Iron deficiency (see inter-veinal chlorosis)
- Yellowing or browning which starts at the leaf margins and extends between the leaf veins, affects older leaves first – Manganese deficiency(see inter-veinal chlorosis)
- Yellow (or occasionally red or brown) patches grow between leaf veins and leaves fall early – Magnesium deficiency(see inter-veinal chlorosis)
- Foliage turns blue-green and later yellow, and may be partly wilted – Copper deficiency
- Yellowish mottling on leaves which also become elongated and twisted – Molybdenum deficiency
What causes it
Nutrient deficiencies, either due to the nutrient lacking in the growing media or because other growing conditions are preventing the plant from taking up the nutrient (eg alkaline conditions or waterlogging). The nature of the chlorsis can indicate the nutrient which the plant requires.
Why it’s a problem
The discolouration of the leaves is unsightly. In more extreme cases the plant’s growth, flowering and fruiting will be reduced.
Where you are likely to find it
Any plants can be affected, but particularly nutrient deficiencies are more common on certain plants, such as ericaceous plants.
How to prevent it
Ensure that plants are growing in appropriate situations and have access to the right level of nutrients and water.
How to get rid of it
Identify the nutrient that is lacking and feed the plant (a foliar feed will usually have a quicker effect). Where environmental conditions are causing/worsening the deficiency, ensure these are remedied.
Is it good for anything?!
Not really, but it is an indicator that the plant isn’t happy with its growing conditions, which could lead to worse problems if not dealt with.
Other useful information
Other problems can also cause similar symptoms. Where the yellowed areas on the leaf are in clearly defined spots or blotches, this is more likely to be a fungal infection than chlorosis. Drought conditions can cause a general dulling of the leaf colour. Inadequate lighting or waterlogging can lead to the leaves, and plant as a whole, yellowing.