Zn deficiency in Pelargonium

Zn deficiency in Pelargonium

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Scientific Name
Zinc (Zn)
Atomic Number
30
Atomic Weight u
65.38
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Zinc (Zn) for use in Pot and Bedding Plants

  • Zinc sulfate (ZnSO₄·7H₂O, “White vitriol”) – soluble, common foliar/substrate application.
  • Zinc sulfate monohydrate (ZnSO₄·H₂O) – slightly more concentrated form of zinc sulfate.
  • Zinc nitrate [Zn(NO₃)₂·6H₂O] – highly soluble, provides Zn and N together.
  • Chelated zinc (Zn-EDTA, Zn-DTPA, Zn-EDDHA) – stable, effective under varying pH, often used in fertigation.
  • Zinc oxide (ZnO) – slow-release, less soluble, often in granular/controlled-release fertilizers.
  • Zinc carbonate (ZnCO₃, “Smithsonite”) – less soluble, slow-release source.
  • Zinc chloride (ZnCl₂) – soluble but less common in horticulture.
  • Zinc frits (glass-fused micronutrients containing Zn) – used in slow-release formulations.

Zinc (Zn) Deficiency in Pelargonium (Pot and Bedding Plants)

Symptoms

  • Affects younger leaves first (Zn is only slightly mobile in plants).
  • Leaf size reduction: Small, narrow, “little leaf” appearance.
  • Interveinal chlorosis: Pale areas between veins, veins remain green.
  • Distortion: Young leaves may be puckered, twisted, or rosetted.
  • Internode shortening: Compact, bushy growth habit.
  • Flowering impact: Reduced flower bud initiation and smaller blooms.

Causes

  • High substrate pH (>6.5) → reduces Zn solubility and uptake.
  • Excess phosphorus fertilization → antagonizes Zn absorption.
  • High CaCO₃ content in growing media.
  • Low organic matter / CEC in substrates → Zn easily leached.
  • Imbalanced fertilization without micronutrient supplementation.

Correction

  • Foliar sprays: Zinc sulfate (ZnSO₄·7H₂O) at 0.1–0.25% provides rapid correction.
  • Substrate application:
  • Use chelated Zn sources (Zn-EDTA, Zn-DTPA) for better availability.
  • Apply controlled-release or granular micronutrient blends at planting.
  • Balanced fertilization: Ensure fertilizers used supply Zn regularly.

Prevention

  • Maintain substrate pH 5.5–6.0 for optimal micronutrient availability.
  • Incorporate Zn-containing fertilizers into standard nutrition programs.
  • Avoid overuse of phosphorus fertilizers.
  • Conduct regular substrate/tissue testing to monitor micronutrient balance.

Zn deficiency in Pelargonium

Zinc (Zn)
Scientific Name
Zinc (Zn)
Atomic Number
30
Atomic Weight u
65.38
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Zinc (Zn) for use in Pot and Bedding Plants

  • Zinc sulfate (ZnSO₄·7H₂O, “White vitriol”) – soluble, common foliar/substrate application.
  • Zinc sulfate monohydrate (ZnSO₄·H₂O) – slightly more concentrated form of zinc sulfate.
  • Zinc nitrate [Zn(NO₃)₂·6H₂O] – highly soluble, provides Zn and N together.
  • Chelated zinc (Zn-EDTA, Zn-DTPA, Zn-EDDHA) – stable, effective under varying pH, often used in fertigation.
  • Zinc oxide (ZnO) – slow-release, less soluble, often in granular/controlled-release fertilizers.
  • Zinc carbonate (ZnCO₃, “Smithsonite”) – less soluble, slow-release source.
  • Zinc chloride (ZnCl₂) – soluble but less common in horticulture.
  • Zinc frits (glass-fused micronutrients containing Zn) – used in slow-release formulations.
Zn deficiency in Pelargonium
Image Source: USDA (USA), care of ICL

Zinc (Zn) Deficiency in Pelargonium (Pot and Bedding Plants)

Symptoms

  • Affects younger leaves first (Zn is only slightly mobile in plants).
  • Leaf size reduction: Small, narrow, “little leaf” appearance.
  • Interveinal chlorosis: Pale areas between veins, veins remain green.
  • Distortion: Young leaves may be puckered, twisted, or rosetted.
  • Internode shortening: Compact, bushy growth habit.
  • Flowering impact: Reduced flower bud initiation and smaller blooms.

Causes

  • High substrate pH (>6.5) → reduces Zn solubility and uptake.
  • Excess phosphorus fertilization → antagonizes Zn absorption.
  • High CaCO₃ content in growing media.
  • Low organic matter / CEC in substrates → Zn easily leached.
  • Imbalanced fertilization without micronutrient supplementation.

Correction

  • Foliar sprays: Zinc sulfate (ZnSO₄·7H₂O) at 0.1–0.25% provides rapid correction.
  • Substrate application:
  • Use chelated Zn sources (Zn-EDTA, Zn-DTPA) for better availability.
  • Apply controlled-release or granular micronutrient blends at planting.
  • Balanced fertilization: Ensure fertilizers used supply Zn regularly.

Prevention

  • Maintain substrate pH 5.5–6.0 for optimal micronutrient availability.
  • Incorporate Zn-containing fertilizers into standard nutrition programs.
  • Avoid overuse of phosphorus fertilizers.
  • Conduct regular substrate/tissue testing to monitor micronutrient balance.