Mn deficiency in Pelargonium

Mn deficiency in Pelargonium

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Scientific Name
Manganese (Mn)
Atomic Number
25
Atomic Weight u
54.938
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Manganese (Mn) for use in Pot and Bedding Plants

  • Manganese sulfate (MnSO₄·Hâ‚‚O or MnSO₄·4Hâ‚‚O) – highly soluble, fast-acting; commonly used in foliar sprays or substrate applications.
  • Manganese oxide (MnO) – slow-release form, used in granular fertilizers.
  • Manganese carbonate (MnCO₃) – less soluble, provides gradual Mn supply.
  • Manganese chelates (Mn-EDTA, Mn-DTPA, Mn-EDDHA) – stable in wider pH ranges, ideal for fertigation or foliar application.
  • Manganese chloride (MnCl₂·4Hâ‚‚O) – soluble, occasionally used in hydroponics or foliar sprays.
  • Manganese frits – glass-fused micronutrient carriers providing slow-release Mn in controlled-release formulations.

Manganese (Mn) Deficiency in Pelargonium – Pot and Bedding Plants

Symptoms

  • Interveinal chlorosis on young leaves (yellowing between green veins).
  • Leaves may appear mottled or have a pale green to yellowish tint.
  • Reduced growth and smaller leaf size.
  • In severe cases, brown necrotic spots may develop on leaf tissue.

Causes

  • Low manganese availability in the substrate, often due to high pH (alkaline) conditions.
  • Excessive levels of other cations such as calcium, magnesium, or iron that compete with Mn uptake.
  • Poor substrate aeration or overwatering, which can limit root absorption.
  • Use of low-Mn fertilizers or prolonged cropping without Mn supplementation.

Correction

  • Apply manganese sulfate (MnSO₄·Hâ‚‚O or MnSO₄·4Hâ‚‚O) to the substrate or as a foliar spray.
  • Use chelated forms (Mn-EDTA, Mn-DTPA, Mn-EDDHA) for quick correction, especially in alkaline media.
  • Adjust substrate pH to slightly acidic (around 5.5–6.5) to improve Mn availability.

Prevention

  • Incorporate a balanced micronutrient program, including manganese, during routine fertilization.
  • Monitor substrate pH and maintain it within the optimal range for Pelargonium.
  • Avoid excessive use of high-calcium fertilizers that can reduce Mn uptake.
  • Ensure adequate drainage and aeration to support root nutrient absorption.

Mn deficiency in Pelargonium

Manganese (Mn)
Scientific Name
Manganese (Mn)
Atomic Number
25
Atomic Weight u
54.938
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Manganese (Mn) for use in Pot and Bedding Plants

  • Manganese sulfate (MnSO₄·Hâ‚‚O or MnSO₄·4Hâ‚‚O) – highly soluble, fast-acting; commonly used in foliar sprays or substrate applications.
  • Manganese oxide (MnO) – slow-release form, used in granular fertilizers.
  • Manganese carbonate (MnCO₃) – less soluble, provides gradual Mn supply.
  • Manganese chelates (Mn-EDTA, Mn-DTPA, Mn-EDDHA) – stable in wider pH ranges, ideal for fertigation or foliar application.
  • Manganese chloride (MnCl₂·4Hâ‚‚O) – soluble, occasionally used in hydroponics or foliar sprays.
  • Manganese frits – glass-fused micronutrient carriers providing slow-release Mn in controlled-release formulations.
Mn deficiency in Pelargonium
Image Source: USDA (USA), care of ICL

Manganese (Mn) Deficiency in Pelargonium – Pot and Bedding Plants

Symptoms

  • Interveinal chlorosis on young leaves (yellowing between green veins).
  • Leaves may appear mottled or have a pale green to yellowish tint.
  • Reduced growth and smaller leaf size.
  • In severe cases, brown necrotic spots may develop on leaf tissue.

Causes

  • Low manganese availability in the substrate, often due to high pH (alkaline) conditions.
  • Excessive levels of other cations such as calcium, magnesium, or iron that compete with Mn uptake.
  • Poor substrate aeration or overwatering, which can limit root absorption.
  • Use of low-Mn fertilizers or prolonged cropping without Mn supplementation.

Correction

  • Apply manganese sulfate (MnSO₄·Hâ‚‚O or MnSO₄·4Hâ‚‚O) to the substrate or as a foliar spray.
  • Use chelated forms (Mn-EDTA, Mn-DTPA, Mn-EDDHA) for quick correction, especially in alkaline media.
  • Adjust substrate pH to slightly acidic (around 5.5–6.5) to improve Mn availability.

Prevention

  • Incorporate a balanced micronutrient program, including manganese, during routine fertilization.
  • Monitor substrate pH and maintain it within the optimal range for Pelargonium.
  • Avoid excessive use of high-calcium fertilizers that can reduce Mn uptake.
  • Ensure adequate drainage and aeration to support root nutrient absorption.