Reading the signs for boron deficiency in pepper plants

:: Monday, April 1, 2024 :: Posted By Abigail Jiang
The leaves of pepper plants provide a narrative to its nutrient needs. Boron deficiency often shows up in the leaves as loss of color, yellowing, and leaf cupping. Observation of plant leaves allows producers to gain early and valuable insights into plant nutrition. This proactive approach can let producers know that an application of boron may be needed.

Boron deficiency in pepper plants can cause a variety of issues including:
  • Underdeveloped roots
  • Flower and/or bud drop 
  • Stunted or terminated flowers
  • Dwarfed plants   
  • Uneven fruit maturity and fruit damage 

Start with the soil

Soil application of Granubor® or Fertibor® is important for root development in the beginning stages of pepper growth. The pH level of the soil can impact a plant’s uptake of boron through the roots, and ultimately the rest of the plant. Factors such as drought, sandy soils, alkaline  soils, and cold and wet weather can all affect boron availability in pepper growing regions. In addition, different varieties of pepper plants may require different amounts of boron. Foliar application with Solubor® may be recommended as a complementary application to soil when needed. 

The presence of other elements in the soil and their uptake in pepper plants can also be affected by the amount of boron available for the plant to use. Boron plays a symbiotic role with calcium in stabilization of plant tissue aw well as plant strength—helping ensure a high-quality crop and yield. Consult your local agronomic professional and conduct soil or tissue analysis to find out what levels of boron you need to add for your pepper production. 

Ensure robust flower formation

Monitoring peppers at flowering period is crucial—especially since peppers tend to require more boron during this phase. Because boron is associated with the transport of photoassimilates, it plays a unique role in the formation of pepper flavor, color, and texture. As a grower, it's essential to grasp the significance of monitoring boron levels at this specific stage to prevent any harm to fruit formation.

Achieving a pepper yield involves paying close attention to all these environmental factors, but also aligning your expectations for yield as a grower. Striking the right balance between optimizing yields and managing fertilizer expenses is pivotal in meeting your growth objectives. U.S. Borax products such as Granubor , Fertibor , and Solubor  provide a premium boron product for better results in your fields. 

Contact our sales team for more informaiton


Pepper crop guide
U.S. Borax products

Sarafi, Eleana & Siomos, Anastasios & Tsouvaltzis, Pavlos & Therios, Ioannis & Chatzissavvidis, Christos. (2018). The influence of Boron on pepper plants nutritional status and nutrient efficiency. Journal of soil science and plant nutrition. 18.10.4067/S0718-95162018005001903. 


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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