Manganese (Mn) Deficiency

Manganese (Mn) Deficiency

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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 Horticultural Production

  • Manganese sulfate (MnSO₄·H₂O or MnSO₄·4H₂O, “Manganous sulfate”) – highly soluble, fast-acting; widely used for foliar sprays or substrate application.
  • Manganese nitrate [Mn(NO₃)₂·xH₂O] – soluble, supplies both Mn and N; effective in fertigation and foliar programs.
  • Manganese chloride (MnCl₂·4H₂O) – soluble, occasionally used in foliar sprays or hydroponics; rapid correction but less common.
  • Manganese chelates (Mn-EDTA, Mn-DTPA, Mn-EDDHA) – stable across a wide pH range (especially effective in alkaline media); suitable for fertigation and foliar feeding.
  • Manganese oxide (MnO, MnO₂, Mn₃O₄) – low solubility, slow-release; typically used in granular or controlled-release fertilizers.
  • Manganese carbonate (MnCO₃) – moderately soluble; provides a gradual Mn supply when incorporated into substrates.
  • Manganese frits (varied composition, “Slow-release Mn frits”) – glass-fused carriers that supply Mn slowly in controlled-release formulations.

Manganese (Mn) Deficiency

Container Nursery Stock, Pot & Bedding Plants

Symptoms

  • Interveinal chlorosis (yellowing between veins) on younger leaves while veins remain green.
  • Leaves may appear mottled, patchy, pale green to yellow, or show distortion and cupping in severe cases.
  • Reduced growth, smaller leaf size, weaker stems, and stunted overall development.
  • Necrotic spots, brown speckling, or leaf tip burn may occur in prolonged deficiency.
  • Delayed or reduced flowering and overall loss of ornamental quality in bedding plants.

Causes

  • Low manganese availability, often due to high substrate pH (>6.0–6.5) or excessive liming.
  • Alkaline or calcareous soils, or aged growing media lacking Mn supply.
  • Excessive levels of competing cations (Fe, Mg, Ca, or P) interfering with Mn uptake.
  • Poor aeration, waterlogging, or overwatering reducing root function and Mn solubility.
  • Use of poorly balanced or low-Mn fertilizers over prolonged cropping cycles.

Correction

  • Foliar sprays: Manganese sulfate (MnSO₄·H₂O or MnSO₄·4H₂O) or chelated forms (Mn-EDTA, Mn-DTPA, Mn-EDDHA) for rapid uptake.
  • Substrate applications: Incorporate Mn fertilizers or controlled-release formulations into the growing medium.
  • pH management: Maintain slightly acidic conditions (optimal range pH 5.5–6.5) to maximize Mn solubility.
  • Water management: Improve drainage and avoid prolonged waterlogging to ensure healthy root function.

Prevention

  • Regularly monitor substrate pH and Mn levels through testing.
  • Maintain a balanced nutrient program, including Mn, and avoid excess antagonistic cations (Ca, Mg, Fe, P).
  • Incorporate slow-release or chelated Mn in fertilizer programs for container crops.
  • Ensure good substrate drainage and aeration to support efficient nutrient uptake.

Manganese (Mn) Deficiency

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 Horticultural Production

  • Manganese sulfate (MnSO₄·H₂O or MnSO₄·4H₂O, “Manganous sulfate”) – highly soluble, fast-acting; widely used for foliar sprays or substrate application.
  • Manganese nitrate [Mn(NO₃)₂·xH₂O] – soluble, supplies both Mn and N; effective in fertigation and foliar programs.
  • Manganese chloride (MnCl₂·4H₂O) – soluble, occasionally used in foliar sprays or hydroponics; rapid correction but less common.
  • Manganese chelates (Mn-EDTA, Mn-DTPA, Mn-EDDHA) – stable across a wide pH range (especially effective in alkaline media); suitable for fertigation and foliar feeding.
  • Manganese oxide (MnO, MnO₂, Mn₃O₄) – low solubility, slow-release; typically used in granular or controlled-release fertilizers.
  • Manganese carbonate (MnCO₃) – moderately soluble; provides a gradual Mn supply when incorporated into substrates.
  • Manganese frits (varied composition, “Slow-release Mn frits”) – glass-fused carriers that supply Mn slowly in controlled-release formulations.
Manganese (Mn) Deficiency
Image Source: Everris Research (NL), LVG Bad Zwischenahn (D), LVG Bad Zwischenahn (D), PPO Boskoop (NL), USDA (USA), WUR Glastuinbouw, Bleiswijk (NL), care of ICL

Manganese (Mn) Deficiency

Container Nursery Stock, Pot & Bedding Plants

Symptoms

  • Interveinal chlorosis (yellowing between veins) on younger leaves while veins remain green.
  • Leaves may appear mottled, patchy, pale green to yellow, or show distortion and cupping in severe cases.
  • Reduced growth, smaller leaf size, weaker stems, and stunted overall development.
  • Necrotic spots, brown speckling, or leaf tip burn may occur in prolonged deficiency.
  • Delayed or reduced flowering and overall loss of ornamental quality in bedding plants.

Causes

  • Low manganese availability, often due to high substrate pH (>6.0–6.5) or excessive liming.
  • Alkaline or calcareous soils, or aged growing media lacking Mn supply.
  • Excessive levels of competing cations (Fe, Mg, Ca, or P) interfering with Mn uptake.
  • Poor aeration, waterlogging, or overwatering reducing root function and Mn solubility.
  • Use of poorly balanced or low-Mn fertilizers over prolonged cropping cycles.

Correction

  • Foliar sprays: Manganese sulfate (MnSO₄·H₂O or MnSO₄·4H₂O) or chelated forms (Mn-EDTA, Mn-DTPA, Mn-EDDHA) for rapid uptake.
  • Substrate applications: Incorporate Mn fertilizers or controlled-release formulations into the growing medium.
  • pH management: Maintain slightly acidic conditions (optimal range pH 5.5–6.5) to maximize Mn solubility.
  • Water management: Improve drainage and avoid prolonged waterlogging to ensure healthy root function.

Prevention

  • Regularly monitor substrate pH and Mn levels through testing.
  • Maintain a balanced nutrient program, including Mn, and avoid excess antagonistic cations (Ca, Mg, Fe, P).
  • Incorporate slow-release or chelated Mn in fertilizer programs for container crops.
  • Ensure good substrate drainage and aeration to support efficient nutrient uptake.