Mg deficiency in Magnolia

Mg deficiency in Magnolia

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Scientific Name
Magnesium (Mg)
Atomic Number
12
Atomic Weight u
24.305
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Magnesium (Mg) for use in Container Nursery Stock

  • Magnesium sulfate (MgSO₄·7H₂O, “Epsom salt”) – highly soluble, quick foliar or substrate correction.
  • Magnesium sulfate monohydrate (MgSO₄·H₂O) – more concentrated, soluble form of magnesium sulfate.
  • Magnesium oxide (MgO) – slow-release, less soluble; suitable for incorporation into media.
  • Dolomitic lime (CaMg(CO₃)₂) – supplies both calcium and magnesium; raises substrate pH slightly.
  • Magnesium carbonate (MgCO₃) – slowly soluble, provides magnesium gradually over time.
  • Magnesium nitrate (Mg(NO₃)₂·6H₂O) – highly soluble, supplies both Mg and N; suitable for fertigation.
  • Magnesium chloride (MgCl₂·6H₂O) – soluble, sometimes used in foliar sprays or hydroponics.

Magnesium (Mg) Deficiency in Magnolia – Container Nursery Stock

Symptoms

  • Interveinal chlorosis: yellowing of leaf tissue between green veins, usually starting on older leaves.
  • Leaf curling or distortion in severe cases.
  • Reduced growth and smaller leaves.
  • In extreme deficiency, leaf necrosis may develop along the edges.

Causes

  • Magnesium is a mobile nutrient, so deficiencies often appear in older leaves first.
  • Low magnesium levels in the substrate or potting media.
  • High levels of competing cations (potassium, calcium, ammonium) reducing Mg uptake.
  • Acidic soils or media pH below optimal range (pH < 5.5).
  • Excessive leaching due to high rainfall or over-irrigation.

Correction

  • Foliar spray with magnesium sulfate (MgSO₄·7H₂O) for rapid symptom relief.
  • Incorporate soluble magnesium fertilizers into the substrate (e.g., MgSO₄, Mg(NO₃)₂).
  • Adjust irrigation practices to reduce nutrient leaching.
  • Ensure balanced fertilization to avoid excessive competing cations.

Prevention

  • Test potting media periodically for magnesium levels and pH.
  • Apply magnesium-containing fertilizers as part of a routine nutrient program.
  • Maintain substrate pH within optimal range for Magnolia (around 5.5–6.5).
  • Avoid overuse of high-potassium or high-calcium fertilizers that can antagonize Mg uptake.

Mg deficiency in Magnolia

Magnesium (Mg)
Scientific Name
Magnesium (Mg)
Atomic Number
12
Atomic Weight u
24.305
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Magnesium (Mg) for use in Container Nursery Stock

  • Magnesium sulfate (MgSO₄·7H₂O, “Epsom salt”) – highly soluble, quick foliar or substrate correction.
  • Magnesium sulfate monohydrate (MgSO₄·H₂O) – more concentrated, soluble form of magnesium sulfate.
  • Magnesium oxide (MgO) – slow-release, less soluble; suitable for incorporation into media.
  • Dolomitic lime (CaMg(CO₃)₂) – supplies both calcium and magnesium; raises substrate pH slightly.
  • Magnesium carbonate (MgCO₃) – slowly soluble, provides magnesium gradually over time.
  • Magnesium nitrate (Mg(NO₃)₂·6H₂O) – highly soluble, supplies both Mg and N; suitable for fertigation.
  • Magnesium chloride (MgCl₂·6H₂O) – soluble, sometimes used in foliar sprays or hydroponics.
Mg deficiency in Magnolia
Image Source: LVG Bad Zwischenahn (D), care of ICL

Magnesium (Mg) Deficiency in Magnolia – Container Nursery Stock

Symptoms

  • Interveinal chlorosis: yellowing of leaf tissue between green veins, usually starting on older leaves.
  • Leaf curling or distortion in severe cases.
  • Reduced growth and smaller leaves.
  • In extreme deficiency, leaf necrosis may develop along the edges.

Causes

  • Magnesium is a mobile nutrient, so deficiencies often appear in older leaves first.
  • Low magnesium levels in the substrate or potting media.
  • High levels of competing cations (potassium, calcium, ammonium) reducing Mg uptake.
  • Acidic soils or media pH below optimal range (pH < 5.5).
  • Excessive leaching due to high rainfall or over-irrigation.

Correction

  • Foliar spray with magnesium sulfate (MgSO₄·7H₂O) for rapid symptom relief.
  • Incorporate soluble magnesium fertilizers into the substrate (e.g., MgSO₄, Mg(NO₃)₂).
  • Adjust irrigation practices to reduce nutrient leaching.
  • Ensure balanced fertilization to avoid excessive competing cations.

Prevention

  • Test potting media periodically for magnesium levels and pH.
  • Apply magnesium-containing fertilizers as part of a routine nutrient program.
  • Maintain substrate pH within optimal range for Magnolia (around 5.5–6.5).
  • Avoid overuse of high-potassium or high-calcium fertilizers that can antagonize Mg uptake.