Iron deficiency (chlorosis)
Bright yellow young leaves threaded with a fine network of green veins — a lime-induced deficiency, worst on calcareous soils and in fruit crops.
- Nutrient type
- Micronutrient
- Mobility in plant
- Immobile
- Symptoms start on
- New (upper) leaves
- Most at risk
- Calcareous, high-pH, waterlogged soils
Overview
Iron is essential for making chlorophyll, so a shortage bleaches the leaf to bright yellow or almost white while the finest veins stay green — a striking net-like pattern called iron chlorosis. Because iron is immobile in the plant, it always shows on the youngest leaves and the growing tips first.
The twist is that iron is rarely actually absent from soil. It is usually locked up — made unavailable by high pH in calcareous and over-limed soils, by waterlogging, or by too much phosphorus or bicarbonate in irrigation water. So the fix is often not "add iron to the soil" (where it just gets locked up again) but to spray it on the leaves or acidify the root zone.
How to spot it
- The youngest leaves turn bright yellow to nearly white between the veins, while even the finest veins stay green — a delicate green net on a yellow leaf.
- It always starts at the top of the plant and on new shoots; older leaves lower down stay green.
- In severe cases the whole young leaf bleaches, browns at the edges and the growing tip dies back.
- Common in citrus, grapes, pomegranate and other fruit on calcareous soil, and in soybean/groundnut on high-pH patches.
Why it happens
- High soil pH — calcareous or over-limed soils — chemically locks iron into unavailable forms even when plenty is present.
- Waterlogging and poor aeration, and bicarbonate-rich irrigation water, both worsen lime-induced chlorosis.
- Excess phosphorus in the soil ties up iron.
- Sandy soils genuinely low in iron, though this is the less common cause.
Confirm before you spend
- Iron chlorosis (green net on a bright-yellow young leaf) looks like manganese deficiency; iron’s vein network is finer and the leaf paler. Both hit young leaves — a foliar test spray on a few leaves that greens up confirms which.
- It is nearly always a high-pH / waterlogging problem, not an absence of iron — so check soil pH and drainage before buying soil iron.
How to correct it
- Spray the leaves with 0.5–1% ferrous sulphate (roughly 5–10 g/litre), repeated 2–3 times at 10–15 day intervals — foliar iron is the reliable fix because soil iron re-locks in high-pH soil.
- For fruit trees on calcareous soil, use a chelated iron (Fe-EDDHA), which stays available at high pH, applied to the soil near the roots.
- Improve drainage and avoid over-irrigation; correcting waterlogging alone often greens up a lime-induced chlorosis.
- Do not just dump more ferrous sulphate on a calcareous soil expecting a lasting cure — it will lock up; treat the pH/drainage cause and feed the leaves.
Prevent it coming back
- On calcareous soils, choose tolerant crops and rootstocks, and add organic matter/FYM, which chelates iron and keeps it available.
- Manage irrigation to avoid waterlogging and pick lower-bicarbonate water where you can.
- Keep phosphorus balanced rather than excessive, and acidify the root zone of chronic fruit trees where practical.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My leaves are yellow but the veins are still bright green. What is it?
That fine green vein network on a yellow young leaf is classic iron chlorosis. It usually means the iron is locked up by high soil pH or waterlogging, not that the soil lacks iron. Spray 0.5–1% ferrous sulphate on the leaves for a quick fix, and address soil pH and drainage for a lasting one.
I keep adding iron to the soil but it does not help. Why?
On calcareous or over-limed soil, ordinary iron (ferrous sulphate) re-locks into unavailable forms within days. That is why soil iron often fails. Use a foliar ferrous sulphate spray, or a chelated iron (Fe-EDDHA) for trees, and fix the underlying high pH / waterlogging rather than adding more soluble iron.
How do I tell iron from manganese deficiency?
Both yellow the young leaves between the veins. Iron chlorosis is brighter, almost white, with a finer green vein net; manganese leaves a broader green band along the veins and a duller, mottled yellow. A test foliar spray of each on a few leaves — whichever greens up is the one you are short of.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.