Ultra-Fine Soluble Boron for Fertigation, Foliar & Hydroponic Use

Solubor by US Borax (Rio Tinto) is the industry-standard soluble boron fertilizer — delivering 20.5% boron (B) guaranteed (20.9% typical) as disodium octaborate tetrahydrate (Na₂B₈O₁₃·4H₂O). With a particle size under 75 microns, Solubor disperses and dissolves rapidly even at low temperatures, making it the preferred boron source for fertigation injection, foliar programs, hydroponic nutrient solutions, and liquid fertilizer formulation.

Boron is essential for cell wall formation, pollen viability, sugar transport, and calcium utilization. Deficiency is common in sandy, leached, or high-pH soils and shows up quickly in fast-growing tissue. Solubor’s amorphous particle structure and high inherent solubility make it the most reliable way to correct or prevent boron deficiency at any scale.

Guaranteed Analysis

• Boron (B): 20.5% guaranteed (20.9% typical)
• Formula: Na₂B₈O₁₃·4H₂O — Disodium Octaborate Tetrahydrate
• Particle size: <75 microns
• Target range in nutrient solution: 0.1–0.5 ppm B

Application Rates

• Hydroponic stock concentrate: Dissolve 0.25 g per liter of pure water; apply at 5 mL/liter (19 mL/gallon) to achieve 0.25 ppm B in working solution
• Fertigation & foliar: Apply per label recommendations; consult a certified crop advisor or agronomist for crop-specific rates

Key Features

• 20.5% boron — highest-concentration soluble boron fertilizer; economical use rates
• Ultra-fine <75 micron particle size — rapid wetting and dispersion, even in cold water
• Minimal crystallization effect — up to 2.7% Solubor can be added to common liquid fertilizer formulations while maintaining crystallization temperatures below 1.7°C (35°F)
• pH buffering action — slight buffering maintains solution pH stability
• Versatile — suitable for fertigation, foliar spray, hydroponic, solid fertilizer coating, and liquid formulation
• 50 lb bag — commercial scale; ideal for greenhouse operations and large fertigation programs

Use in accordance with recommendations of a qualified individual or institution. Tech Data Sheet | Spec Sheet | Safety Data Sheet | Label | Heavy Metals Report