{Persea americana}

Boron Deficiency in Avocados

Boron is a key element for proper avocado nutrition. Lack of boron can cause:

  • Malformed fruit
  • Necrotic spots on the fruit and seed
  • Spongy stem tissue
  • Poor fruit set from improper pollen tube elongation

Research has shown that boron amendments in avocado affected by boron deficiency can increase yield, increase quality of fruit produced, and strengthen root development.

View field studies
Avocado (South Africa)
Avocado Resource
Peduncle position comparison (PDF)

Spotting Boron Deficiency in Avocado

How much boron is enough?

The amount of boron fertilizer needed depends on the soil and climate in which the avocado is grown, the seasonal growing conditions encountered that year, and the timing and method of boron application.

Rates of boron fertilization should be based on soil tests and/or plant analyses, previous experience, yield and quality goals, timing and application methods. Standard ranges of boron fertilization are normally suggested to meet avocado needs under average local conditions.

Timing your boron application

  • Boron can be applied using a foliar spray of Solubor® while flowers are at the cauliflower stage or immediately after flower emergence
  • Liquid suspensions of boron using either Fertibor® or Solubor can be injected into the soil under the canopy during periods of root flush
  • Season-long applications of boron can be achieved by topdressing Granubor® on the soil under the canopy

U.S. Borax Products for Avocado

15% Boron |  | OMRI Certified
Optimum product for suspensions

A fine crystalline borate ideal for NPK compound fertilizers and suspensions. Manufactured as free-flowing granules, Fertibor is easily handled and offers superior flow and consistency.

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15% Boron |  | OMRI Certified
Made especially for bulk blenders

A pure, 100% water-soluble micronutrient that meets boron demand during the growing season. Made especially for bulk blenders, Granubor helps to ensure uniform distribution in nutritional blends and in the field.

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20.5% Boron |  | OMRI Certified
Product of choice for foliar applications

A concentrated, highly soluble, and fast dissolving powder that is ideal for foliar and other sprays. With the highest concentration of boron in any approved product, Solubor is an economical choice for nutritional formulations.

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20.8% Boron
Boron for fertilizer manufacturing

This refined U.S. Borax product is made from the dehydration and fusion of borax. Depending on the grade, Anhybor can be used to produce boron-enriched compound fertilizers or to coat different fertilizer products, such as NPK blends with the aid of a binder.

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10% Boron
Solubor Flow
For fertigation or hydroponic growing

First and only aqueous suspension of sodium borate microcrystals.

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14.5% Boron | 29% Zinc
Perfect combination of zinc and boron

Because zinc and boron deficiency are widespread around the world, a product with both nutrients is a good fit in many regions. Zincubor brings these two important micronutrients together in one product.

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Calculate Your ROI

Soil Application (Suggested rates of application)

  Granubor Fertibor
LBS/ACRE 2.5 - 7.1 2.5 - 7.1
KG/HA 1.1 - 3.2 1.1 - 3.2

Foliar Application (Suggested rates of application)

LBS/ACRE 1.8 - 5.3
KG/HA .81 - 2.0
Value in Use
Current Yield (Per Acre)
Expected Sale Price

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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