Give your crops full access to boron

Granubor | 15% Boron | 100% Soluble

Proven to correct boron deficiency and improve crop yields

With Granubor®, you get what you pay for. Granubor is the only pure, 100% water-soluble granular boron product on the market. Its unmatched solubility provides crops with a fully available and reliable source of boron throughout the growing season. Ultimately, you get higher yields.

See how Granubor delivers a greater ROI than unrefined alternatives.

Made in the USA

  • 15% boron (100% water soluable)
  • Proven to deliver a higher ROI
  • Refined for purity
  • Uniform particle sizes
  • OMRI Listed®
  • Perfect for bulk blend or direct soil application

Don't pay for boron that doesn't work

Ulexite isn't 100% available to plants. That forces you to:

Apply more

Ulexite products release at less than half the rate of Granubor (40%). That means you’ll apply more product to equal just one Granubor application.

Sacrifice more yield

Boron deficient crops can limit yields by 1-4% annually. Ulexite’s partial solubility leaves plants prone to boron deficiency.

Spend more

Unrefined products can cost up to 2.5 times more over a growing season. 

See how you can get more value per acre with Granubor

Discover the ROI you can expect when you choose 100% soluble, completely available refined boron.

Purity matters: Protect your soil’s health

Choosing Granubor is the smartest choice for protecting soil’s long-term health. We mine a special, highly pure form of borate ore and then refine it with physical means only. We do NOT use chemical treatments. So, when Granubor reaches your fields, you won’t have to worry about any harmful contaminants accumulating and compromising future yields.

Pure ingredients only 

Our refining process removes arsenic and other heavy metals. Unrefined products often contain high levels of impurities. 

See the difference 

Organic and traceable 

Granubor comes from one of the world’s cleanest borate sources. Every batch is OMRI listed, made in the USA, and traceable. 

Learn more: OMRI certification  

Field tested, research backed 

We’re a trusted leader in borates research and actively invest in studies to show why purity is so important. 

Explore our research 

Proven consistency

Granubor features consistent particle sizes and a release profile that aligns with crop needs. You can feel confident that you’re supplying the right amount of boron at the right time. 

Even size, even distribution 

We subject every batch of Granubor to tight screening parameters (-4 and +14 mesh), making it easier for you to distribute evenly in the field. 

See distribution field tests  

Perfect for blending 

Granubor’s average particle size (2.8mm) is a perfect fit for bulk blending. Consistent sizing also minimizes risk during bagging, transport, and application. 

Get technical details 

Crush resistant 

Featuring a particle strength of 9 lb per granule, Granubor can withstand force and resist crushing, while maintaining extremely low dust content. 

See product specs 

Addressing boron deficiency

Boron is an essential micronutrient that enables healthier and higher crop yields. Therefore, preventing and correcting boron deficiency is key to optimal growth. 

Learn more


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.

Copyright © 2024 Rio Tinto. All Rights Reserved.