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Iron Deficiency

Q: Why do new top leaves turn yellow with green veins in tomatoes?

This classic symptom is interveinal chlorosis caused by iron deficiency. Iron is required for chlorophyll synthesis but cannot move from older tissues to new growth. The areas between veins turn yellow while veins remain dark green.

Q: Which iron chelate should I use: Fe-EDTA or Fe-EDDHA?

Use Fe-EDDHA if your soil is alkaline (pH > 7.0) or calcareous, as Fe-EDDHA stays stable and plant-available up to pH 9.0. If your soil pH is below 6.5 or for direct foliar spraying, Fe-EDTA (12%) is effective and more economical.

Ferrum Deficientia

Basic Details

Description

Nutrient Info

Identify

Seasonal Calendar

Treatment

FAQs

How to Identify Iron Deficiency on Tomato

Iron Deficiency identification guide illustration

Visible Symptoms

Interveinal chlorosis develops on the youngest, emerging leaves at the top of the plant. The leaf blade turns pale yellow or white, while even the finest veins remain dark green. In severe cases, new leaves emerge completely bleached.

Key Identification Checklist for Tomato Iron Deficiency: 1. Interveinal Chlorosis on Youngest Leaves First: Iron is completely immobile in tomato plant tissues. Symptoms emerge strictly on the youngest leaves and new shoots at the growing tip. The tissue between the veins turns bright yellow, while the vein network stays sharply dark green. 2. Bleached Ivory-White Apical Shoots: In moderate to severe cases, the youngest leaves lose almost all chlorophyll, turning nearly pure white or cream with paper-thin texture. 3. Older Lower Leaves Stay Healthy & Green: Unlike nitrogen deficiency, the mature bottom leaves retain their deep green color and vigorous size. 4. Soil pH Induced (Alkaline Soils): True iron deficiency is most commonly triggered when soil pH exceeds 7.5, or in waterlogged, compacted soils where roots cannot absorb ferric iron (Fe³⁺).

About Iron Deficiency

NameIron Deficiency

Description

Iron deficiency typically occurs in calcareous or alkaline soils (pH > 7.0) where iron becomes insoluble. Because iron is immobile in plant tissue, symptoms appear on young leaves first.

TypeDeficiency

Severity Level Early

Nutrient Role & Deficiency Cause

Affected Growth Stages

VegetativeFlowering

Why It Happens

Iron deficiency typically occurs in calcareous or alkaline soils (pH > 7.0) where iron becomes insoluble. Because iron is immobile in plant tissue, symptoms appear on young leaves first.

Also Known AsIron chlorosis, young leaf yellowing

Seasonal Outbreak Calendar

Outbreak risk and activity timeline for Iron Deficiency based on seasonal climate patterns:

Active Window:February - July

Peak Outbreak:March - May

Critical Crop Stage:Active vegetative flush

JanLow Risk

FebModerate

MarPeak Risk

AprPeak Risk

MayPeak Risk

JunModerate

JulModerate

AugLow Risk

SepLow Risk

OctLow Risk

NovLow Risk

DecLow Risk

Low Outbreak Risk

Active / Moderate Risk

High Risk / Peak Outbreak

Want to see this disease and others mapped across other regions? View Global Outbreak Calendar

Treatment & Correction Guide

Natural & Organic Methods

Elemental Sulfur Soil Acidification (pH > 7.2)

20–25 kg/acre incorporated into top 15 cm soil Broadcast once pre-planting or side-band at early stage Gradual pH drop and iron mobilization over 3–6 weeks

Fermented Humic Acid & Seaweed Extract Drench

5 ml humic acid (12%) + 2 ml seaweed extract per Liter water Drench 300 ml per plant base every 14 days Root iron uptake improvement within 7–10 days

Composted Pine Needle / Leaf Mold Mulch

2–3 inch layer around tomato root zone Single application at transplanting Sustained root zone micro-acidification

Chemical & Professional Control

Chelated Iron (Fe-EDDHA 6%) Soil Drench (Alkaline Soils pH > 7.0)

10–15 g per plant in 2 Liters water (or 1–2 kg/acre via drip) Apply once at symptom onset; repeat in 14 days if needed Rapid greening of new shoot tips in 4–7 days

Chelated Iron (Fe-EDTA 12%) Foliar Spray (Soils with pH < 7.0)

1.0–1.5 g per Liter water with non-ionic wetting agent 2 sprays at 7–10 day intervals during cool morning hours Interveinal greening noticeable in 48–96 hours

Ferrous Sulfate (FeSO4 · 7H2O) Foliar Spray

2.5 g per Liter water buffered with 1 g citric acid Apply twice at 7-day intervals Re-greening begins within 5–7 days

Frequently Asked Questions

Why do new top leaves turn yellow with green veins in tomatoes?

This classic symptom is interveinal chlorosis caused by iron deficiency. Iron is required for chlorophyll synthesis but cannot move from older tissues to new growth. The areas between veins turn yellow while veins remain dark green.

Which iron chelate should I use: Fe-EDTA or Fe-EDDHA?

Use Fe-EDDHA if your soil is alkaline (pH > 7.0) or calcareous, as Fe-EDDHA stays stable and plant-available up to pH 9.0. If your soil pH is below 6.5 or for direct foliar spraying, Fe-EDTA (12%) is effective and more economical.

Can over-watering cause iron chlorosis in tomatoes?

Yes, frequently. Waterlogged soil causes root hypoxia (oxygen starvation) and bicarbonate accumulation, which chemically deactivates iron uptake by tomato roots even when iron is abundantly present in the soil.

How quickly does foliar iron chelate work on tomato leaves?

Foliar applied Fe-EDTA or buffered ferrous sulfate begins restoring green pigment between the veins within 48 to 72 hours, with significant visual improvement across the growing tips in 5 to 7 days.

Does sulfur fix iron deficiency in tomatoes?

Elemental sulfur indirectly fixes iron deficiency in alkaline soils by biological oxidation into sulfuric acid, lowering the soil pH below 7.0 and liberating native locked iron for root uptake over 3 to 6 weeks.

Remedy Disclaimer & Safety Notice

This disease guide is for educational screening purposes only. Pathogen behavior, severity, and host susceptibility can vary dramatically based on seed variety, weather conditions, and regional microclimates. Chemical pesticides and organic treatments are subject to strict regional environmental regulations and registration mandates. Please verify all chemical registrations and review manufacturer safety labels carefully with local certified agronomists or agricultural extension service offices before applying.

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