is it mainly on new growth or old ?
ive added epsom and iron to my citrus
and they greeneds up quite nicely.
Iron deficiency
starts on young terminal leaves and later works inward to the older leaves. However, deficiencies in manganese,
zinc or nitrogen develop on inner or older leaves first and then progress outward.
Symptoms include leaves turning yellow or brown in the margins between the veins which may remain green,
while young leaves may appear to be bleached
magnesium
Due to magnesium’s mobile nature, the plant will first break down chlorophyll in older leaves and transport the Mg to younger leaves
Excess potassium, generally due to fertilizers, further aggravates the stress from magnesium deficiency,[2] as does aluminium toxicity.[3]
Interveinal chlorotic mottling or marbling of the older leaves which proceeds toward the younger leaves as the deficiency becomes more severe.
Manganese (Mn)
deficiency is a plant disorder that is often confused with, and occurs with, iron deficiency. Most common in poorly drained soils, also where organic matter levels are high. Manganese may be unavailable to plants where pH is high.
Nitrogen
It is a component of chlorophyll, so when nitrogen is insufficient, leaves will take on a yellow (chlorotic) appearance down the middle of the leaf. Restricted growth of tops and roots and especially lateral shoots. Plants become spindly with gen eral chlorosis of entire plant to a light green and then a yellowing of older leaves which proceeds toward younger leaves