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Explore our product resources.  

Data Sheet

Discover more product details, including technical features and primary uses of Granubor.

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Safety Data Sheet

Find proper handling and storage information, as well as important supplier details.

Safety data sheet

Specifications Sheets

Get details on chemical and physical specifications.

Specification sheet

Field Studies

Explore our field studies to see how Granubor improves crop performance. 

Field studies

Technical Specifications

Granubor is a calcium-and-magnesium-free borate, produced solely from sodium tetraborate pentahydrate. You’ll find no added impurities, ingredients, fillers, or coatings.  

Technical features include: 

  • 15% boron content 

  • Physically refined, non-chemically treated 

  • Uniform average particle size, matching standard granulated fertilizers 

  • Limited segregation and dust content  

Download product data sheet
Boron (B): 15%
Material required for 1 lb (.45kg) of B: 7 lb (3.18kg)

  • Screened between -4 and +14 mesh.
  • Typical flow rate: 11 lb (4.99kg) per minute
  • Particle strength: 9 lb (4.08kg) per granule
Bulk density
Loose pack: 
57 lb/ft3
Tight pack: 60 lb/ft3 (961 kg/m3)
Angle of repose: 30°
Tight pack: 280

Bulk option (super bags):
2500 lb (1134 kg)
Plastic bags: 50 lb (22.7 kg)

Additional resources


Deliver 100% of the boron you pay for to your crops with Granubor.

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The main differences between ulexites and Granubor

Research data from a percolation study to compare the release rate of various boron sources shows that Granubor provides benefits over ulexites.


Crop Study: Growing Rice in China

Hear the key results of a two-year rice trial, conducted by U.S. Borax and the International Rice Research Institute, on the effect of borates on rice quality and yield in China.

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Corn (Mississippi, USA)

Mississippi, USA (2021): Granubor shows a better performance than the control and ulexite.

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Price of Granubor vs. Ulexite

Price of Granubor vs. Ulexite

The true cost of using less expensive borates: Price per pound of plant available boron

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Why Granubor Is Perfect for Your Crops

Why Granubor Is Perfect for Your Crops

A comparison among boron alternatives on the speed of release of boron, including sources of boron released after 140 days

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Get more Granubor information

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles. Learn more about Rio Tinto.

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