Ca deficiency in Poinsettia

Ca deficiency in Poinsettia

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Scientific Name
Calcium (Ca)
Atomic Number
20
Atomic Weight u
40.078
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Calcium (Ca) for use in Pot and Bedding Plants

  • Calcium nitrate (Ca(NO₃)₂, “Calcium nitrate”) – highly soluble; primary Ca source in fertigation.
  • Calcium chloride (CaCl₂, “Calcium chloride”) – very soluble; rapid foliar correction (use carefully to avoid burn).
  • Calcium sulfate (CaSO₄·2H₂O, “Gypsum”) – sparingly soluble; supplies Ca without raising pH strongly.
  • Calcium carbonate (CaCO₃, “Calcitic lime”) – raises pH while supplying Ca; slow to moderate release.
  • Dolomitic lime (CaMg(CO₃)₂, “Dolomite”) – supplies Ca and Mg; pH adjustment.
  • Calcium hydroxide (Ca(OH)₂, “Hydrated lime”) – fast pH increase; corrective amendment.
  • Calcium chelate (Ca-EDTA, “EDTA-Ca”) – soluble; foliar/specialty use.
  • Calcium acetate (Ca(C₂H₃O₂)₂, “Calcium acetate”) – soluble; used in some liquid formulations.

Calcium (Ca) Deficiency in Poinsettia – Pot and Bedding Plants

Symptoms

  • Symptoms appear on the youngest tissues first (immobile in plant).
  • Deformed, strap-like, or cupped young leaves; tip burn and marginal necrosis common.
  • Weak peduncles and blossom/bud abortion; poor flower quality.
  • Poor root growth with stubby, brittle root tips.

Causes

  • Insufficient Ca supply in fertilizer program or low Ca in irrigation water.
  • Interrupted Ca transport due to irregular moisture or low transpiration (dense canopy, low airflow).
  • Antagonism from excessive NH₄⁺, K⁺ or Mg²⁺ competing with Ca²⁺ uptake.
  • High EC or water stress restricting Ca movement to growing tips.

Correction

  • Supply Ca through calcium nitrate in fertigation; supplement with gypsum for sustained Ca without raising EC excessively.
  • Use foliar calcium chloride for rapid correction on developing tissues (avoid spray burn; apply in cool periods).
  • Maintain consistent substrate moisture to ensure continuous Ca transport.
  • Reduce antagonists (excess NH₄⁺, K⁺, Mg²⁺) and keep EC within target range.

Prevention

  • Ensure a continuous Ca supply in fertigation (e.g., calcium nitrate) or via gypsum in the substrate.
  • Manage climate and spacing to improve transpiration (air movement, temperature control).
  • Irrigate consistently to avoid dry-down cycles that interrupt Ca movement.
  • Limit excess NH₄⁺, K⁺ and Mg²⁺ that compete with Ca²⁺ uptake.
  • Monitor EC and media Ca levels with regular testing.

Ca deficiency in Poinsettia

Calcium (Ca)
Scientific Name
Calcium (Ca)
Atomic Number
20
Atomic Weight u
40.078
Elemental Group
Meso elements (Ca, Mg, S ) | Secondary macronutrients
Available Forms

Available forms of Calcium (Ca) for use in Pot and Bedding Plants

  • Calcium nitrate (Ca(NO₃)₂, “Calcium nitrate”) – highly soluble; primary Ca source in fertigation.
  • Calcium chloride (CaCl₂, “Calcium chloride”) – very soluble; rapid foliar correction (use carefully to avoid burn).
  • Calcium sulfate (CaSO₄·2H₂O, “Gypsum”) – sparingly soluble; supplies Ca without raising pH strongly.
  • Calcium carbonate (CaCO₃, “Calcitic lime”) – raises pH while supplying Ca; slow to moderate release.
  • Dolomitic lime (CaMg(CO₃)₂, “Dolomite”) – supplies Ca and Mg; pH adjustment.
  • Calcium hydroxide (Ca(OH)₂, “Hydrated lime”) – fast pH increase; corrective amendment.
  • Calcium chelate (Ca-EDTA, “EDTA-Ca”) – soluble; foliar/specialty use.
  • Calcium acetate (Ca(C₂H₃O₂)₂, “Calcium acetate”) – soluble; used in some liquid formulations.
Ca deficiency in Poinsettia
Image Source: Everris Research (NL), care of ICL

Calcium (Ca) Deficiency in Poinsettia – Pot and Bedding Plants

Symptoms

  • Symptoms appear on the youngest tissues first (immobile in plant).
  • Deformed, strap-like, or cupped young leaves; tip burn and marginal necrosis common.
  • Weak peduncles and blossom/bud abortion; poor flower quality.
  • Poor root growth with stubby, brittle root tips.

Causes

  • Insufficient Ca supply in fertilizer program or low Ca in irrigation water.
  • Interrupted Ca transport due to irregular moisture or low transpiration (dense canopy, low airflow).
  • Antagonism from excessive NH₄⁺, K⁺ or Mg²⁺ competing with Ca²⁺ uptake.
  • High EC or water stress restricting Ca movement to growing tips.

Correction

  • Supply Ca through calcium nitrate in fertigation; supplement with gypsum for sustained Ca without raising EC excessively.
  • Use foliar calcium chloride for rapid correction on developing tissues (avoid spray burn; apply in cool periods).
  • Maintain consistent substrate moisture to ensure continuous Ca transport.
  • Reduce antagonists (excess NH₄⁺, K⁺, Mg²⁺) and keep EC within target range.

Prevention

  • Ensure a continuous Ca supply in fertigation (e.g., calcium nitrate) or via gypsum in the substrate.
  • Manage climate and spacing to improve transpiration (air movement, temperature control).
  • Irrigate consistently to avoid dry-down cycles that interrupt Ca movement.
  • Limit excess NH₄⁺, K⁺ and Mg²⁺ that compete with Ca²⁺ uptake.
  • Monitor EC and media Ca levels with regular testing.