S deficiency in Poinsettia

S deficiency in Poinsettia

Login to access our suggested solutions.

Scientific Name
Sulfur (S)
Atomic Number
16
Atomic Weight u
32.06
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Sulfur (S) for use in Pot and Bedding Plants

  • Magnesium sulfate (MgSO₄·7H₂O, “Epsom salt”) – soluble, quick-acting source of sulfur and magnesium for foliar or substrate application.
  • Ammonium sulfate ((NH₄)₂SO₄) – provides both nitrogen and sulfur; highly soluble for fertigation or substrate use.
  • Gypsum (CaSO₄·2H₂O) – calcium sulfate; moderately soluble, useful for long-term sulfur correction and calcium supplementation.
  • Potassium sulfate (K₂SO₄, “Sulfate of potash”) – supplies potassium and sulfur; soluble for fertigation or soil amendment.
  • Elemental sulfur (S⁰) – slow-release form; requires microbial oxidation in soil/substrate to become plant-available sulfate.
  • Calcium polysulfide (CaSₓ) – used for sulfur supplementation and pH adjustment; soluble and releases sulfate gradually.
  • Magnesium sulfate monohydrate (MgSO₄·H₂O) – more concentrated, soluble magnesium and sulfur source.
  • Chelated sulfur formulations – specialized products where sulfur is stabilized for foliar or fertigation application.

Sulfur (S) Deficiency in Poinsettia – Pot and Bedding Plants

Symptoms

  • Leaf color: Younger leaves turn uniformly pale green to yellow (S is immobile, so symptoms appear on new growth first).
  • Stunted growth: Overall plant growth is reduced, with shorter internodes.
  • Thin foliage: Leaves may be smaller, thinner, and less vibrant.
  • Delayed flowering: Bracts and flowers may develop later or be smaller in size.

Causes

  • Low sulfur in growing media: Especially common in soilless mixes like peat, coir, or highly leached substrates.
  • Use of sulfur-free fertilizers: Some modern fertilizers supply little or no sulfur.
  • Leaching: Sulfate is soluble and can be lost quickly from the substrate with heavy irrigation.
  • pH and microbial activity: Low microbial activity in media can slow the conversion of elemental sulfur to plant-available sulfate.

Correction

  • Foliar application: Use soluble sulfur sources such as magnesium sulfate (MgSO₄·7H₂O) or ammonium sulfate ((NH₄)₂SO₄) for quick uptake.
  • Substrate amendment: Incorporate gypsum (CaSO₄·2H₂O) or sulfate-containing fertilizers into the growing media.
  • Balanced fertilization: Ensure fertilizers provide adequate sulfur along with N, P, K, and other nutrients.
  • Monitor irrigation: Avoid excessive leaching which can remove sulfate from the substrate.
  • Routine testing: Periodically test media and tissue to ensure sulfur levels remain sufficient for optimal growth.

Prevention

  • Foliar application: Use soluble sulfur sources such as magnesium sulfate (MgSO₄·7H₂O) or ammonium sulfate ((NH₄)₂SO₄) for quick uptake.
  • Substrate amendment: Incorporate gypsum (CaSO₄·2H₂O) or sulfate-containing fertilizers into the growing media.
  • Balanced fertilization: Ensure fertilizers provide adequate sulfur along with N, P, K, and other nutrients.
  • Monitor irrigation: Avoid excessive leaching which can remove sulfate from the substrate.
  • Routine testing: Periodically test media and tissue to ensure sulfur levels remain sufficient for optimal growth.

S deficiency in Poinsettia

Sulfur (S)
Scientific Name
Sulfur (S)
Atomic Number
16
Atomic Weight u
32.06
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Sulfur (S) for use in Pot and Bedding Plants

  • Magnesium sulfate (MgSO₄·7H₂O, “Epsom salt”) – soluble, quick-acting source of sulfur and magnesium for foliar or substrate application.
  • Ammonium sulfate ((NH₄)₂SO₄) – provides both nitrogen and sulfur; highly soluble for fertigation or substrate use.
  • Gypsum (CaSO₄·2H₂O) – calcium sulfate; moderately soluble, useful for long-term sulfur correction and calcium supplementation.
  • Potassium sulfate (K₂SO₄, “Sulfate of potash”) – supplies potassium and sulfur; soluble for fertigation or soil amendment.
  • Elemental sulfur (S⁰) – slow-release form; requires microbial oxidation in soil/substrate to become plant-available sulfate.
  • Calcium polysulfide (CaSₓ) – used for sulfur supplementation and pH adjustment; soluble and releases sulfate gradually.
  • Magnesium sulfate monohydrate (MgSO₄·H₂O) – more concentrated, soluble magnesium and sulfur source.
  • Chelated sulfur formulations – specialized products where sulfur is stabilized for foliar or fertigation application.
S deficiency in Poinsettia
Image Source: Everris Research (NL), LVG Heidelberg (D) care of ICL

Sulfur (S) Deficiency in Poinsettia – Pot and Bedding Plants

Symptoms

  • Leaf color: Younger leaves turn uniformly pale green to yellow (S is immobile, so symptoms appear on new growth first).
  • Stunted growth: Overall plant growth is reduced, with shorter internodes.
  • Thin foliage: Leaves may be smaller, thinner, and less vibrant.
  • Delayed flowering: Bracts and flowers may develop later or be smaller in size.

Causes

  • Low sulfur in growing media: Especially common in soilless mixes like peat, coir, or highly leached substrates.
  • Use of sulfur-free fertilizers: Some modern fertilizers supply little or no sulfur.
  • Leaching: Sulfate is soluble and can be lost quickly from the substrate with heavy irrigation.
  • pH and microbial activity: Low microbial activity in media can slow the conversion of elemental sulfur to plant-available sulfate.

Correction

  • Foliar application: Use soluble sulfur sources such as magnesium sulfate (MgSO₄·7H₂O) or ammonium sulfate ((NH₄)₂SO₄) for quick uptake.
  • Substrate amendment: Incorporate gypsum (CaSO₄·2H₂O) or sulfate-containing fertilizers into the growing media.
  • Balanced fertilization: Ensure fertilizers provide adequate sulfur along with N, P, K, and other nutrients.
  • Monitor irrigation: Avoid excessive leaching which can remove sulfate from the substrate.
  • Routine testing: Periodically test media and tissue to ensure sulfur levels remain sufficient for optimal growth.

Prevention

  • Foliar application: Use soluble sulfur sources such as magnesium sulfate (MgSO₄·7H₂O) or ammonium sulfate ((NH₄)₂SO₄) for quick uptake.
  • Substrate amendment: Incorporate gypsum (CaSO₄·2H₂O) or sulfate-containing fertilizers into the growing media.
  • Balanced fertilization: Ensure fertilizers provide adequate sulfur along with N, P, K, and other nutrients.
  • Monitor irrigation: Avoid excessive leaching which can remove sulfate from the substrate.
  • Routine testing: Periodically test media and tissue to ensure sulfur levels remain sufficient for optimal growth.