Boron (B) Deficiency

Boron (B) Deficiency

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Scientific Name
Boron (B)
Atomic Number
5
Atomic Weight u
10.811
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Boron (B) for Horticultural Production

  • Boric acid (H₃BO₃, “Boric acid”) – soluble; common foliar and drench source.
  • Sodium tetraborate decahydrate (Na₂B₄O₇·10H₂O, “Borax”) – soluble; used in substrate incorporation or stock solutions.
  • Disodium octaborate tetrahydrate (Na₂B₈O₁₃·4H₂O, “Disodium octaborate”) – highly soluble; common in liquid concentrates (e.g., Solubor-type).
  • Boron ethanolamine (“Boron ethanolamine”) – liquid organic complex suitable for fertigation and foliar application.
  • Sodium borate solutions (“Sodium borate solution”) – soluble borate complexes for use in stock solutions and fertigation systems.
  • Boron frits (varied composition, “Slow-release B frits”) – controlled-release sources incorporated into container substrates.

Boron (B) Deficiency

Container Nursery Stock, Pot & Bedding Plants

Symptoms

  • Death or distortion of growing points; new leaves become thick, brittle, or malformed.
  • Short, bushy plants with cracked, corky, or brittle stems and petioles.
  • Flower and bud abortion; poor pollen viability and reduced seed/fruit set.
  • Interveinal chlorosis on young leaves may appear in severe deficiencies.
  • Overall stunted growth and poor canopy development.

Causes

  • Low B levels in fertilizer, water, or soilless substrates prone to leaching.
  • Over-liming or high substrate pH (>6.0–6.5) reducing B solubility and uptake.
  • Antagonism from excess calcium (Ca) or potassium (K), which can restrict B transport.
  • Erratic irrigation or drought stress reducing B mobility to meristematic tissues.

Correction

  • Low-rate B applications: Apply boric acid or sodium borate (e.g., Solubor) as foliar spray or drench; distribute evenly to avoid toxicity.
  • Maintain fertigation supply of 0.3–0.5 ppm B, adjusted based on tissue analysis.
  • Restore uniform irrigation to ensure consistent delivery of B to growing tips.
  • Adjust substrate pH to 5.5–6.0 to improve B availability.

Prevention

  • Maintain 0.3–0.5 ppm B in ongoing fertigation programs, verified by tissue testing.
  • Keep substrate pH in the optimal 5.5–6.0 range; avoid over-liming.
  • Ensure even substrate moisture; avoid drought stress or prolonged drying cycles.
  • Incorporate complete micronutrient blends containing B at planting for sustained release.

Boron (B) Deficiency

Boron (B)
Scientific Name
Boron (B)
Atomic Number
5
Atomic Weight u
10.811
Elemental Group
Micro elements (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn) | Micronutrients
Available Forms

Available forms of Boron (B) for Horticultural Production

  • Boric acid (H₃BO₃, “Boric acid”) – soluble; common foliar and drench source.
  • Sodium tetraborate decahydrate (Na₂B₄O₇·10H₂O, “Borax”) – soluble; used in substrate incorporation or stock solutions.
  • Disodium octaborate tetrahydrate (Na₂B₈O₁₃·4H₂O, “Disodium octaborate”) – highly soluble; common in liquid concentrates (e.g., Solubor-type).
  • Boron ethanolamine (“Boron ethanolamine”) – liquid organic complex suitable for fertigation and foliar application.
  • Sodium borate solutions (“Sodium borate solution”) – soluble borate complexes for use in stock solutions and fertigation systems.
  • Boron frits (varied composition, “Slow-release B frits”) – controlled-release sources incorporated into container substrates.
Boron (B) Deficiency
Image Source: Everris Research (NL), IFAS (USA), LVG Bad Zwischenahn (D), PPO Boskoop (NL), WUR Glastuinbouw, Bleiswijk (NL), care of ICL

Boron (B) Deficiency

Container Nursery Stock, Pot & Bedding Plants

Symptoms

  • Death or distortion of growing points; new leaves become thick, brittle, or malformed.
  • Short, bushy plants with cracked, corky, or brittle stems and petioles.
  • Flower and bud abortion; poor pollen viability and reduced seed/fruit set.
  • Interveinal chlorosis on young leaves may appear in severe deficiencies.
  • Overall stunted growth and poor canopy development.

Causes

  • Low B levels in fertilizer, water, or soilless substrates prone to leaching.
  • Over-liming or high substrate pH (>6.0–6.5) reducing B solubility and uptake.
  • Antagonism from excess calcium (Ca) or potassium (K), which can restrict B transport.
  • Erratic irrigation or drought stress reducing B mobility to meristematic tissues.

Correction

  • Low-rate B applications: Apply boric acid or sodium borate (e.g., Solubor) as foliar spray or drench; distribute evenly to avoid toxicity.
  • Maintain fertigation supply of 0.3–0.5 ppm B, adjusted based on tissue analysis.
  • Restore uniform irrigation to ensure consistent delivery of B to growing tips.
  • Adjust substrate pH to 5.5–6.0 to improve B availability.

Prevention

  • Maintain 0.3–0.5 ppm B in ongoing fertigation programs, verified by tissue testing.
  • Keep substrate pH in the optimal 5.5–6.0 range; avoid over-liming.
  • Ensure even substrate moisture; avoid drought stress or prolonged drying cycles.
  • Incorporate complete micronutrient blends containing B at planting for sustained release.