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Boron Fertilizer for Plants – Best Brands and Application Rates

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Using boron fertilizer for plants, including foliar, liquid, or granular formulas, is one way to meet plants’ boron needs. Other methods are to amend soil pH to 6.0-6.5, deal with soil salinity, increase organic matter, and reduce stressors (low humidity, inadequate watering or extreme temperatures, etcetera.

Discover more on boron fertilizer for plants, including application rates and methods. We will also tell you when to apply and give you some of the best boron fertilizers brands.

However, before that, let us appreciate the role of boron in plants, why plants may lack this essential micronutrient, and what signs you may notice. We will also tell you why soil and plant tissues are important to confirm a deficiency.

Solubor Boron fertilizer for Plants
Solubor Boron fertilizer for plants

Deficiency and why is boron important to plants?

Boron is an essential micronutrient for optimal growth and development, the best crop quality, and maximum yield. It forms part of the cell wall membrane and ensures its integrity, increases sugar transport, and aids in calcium absorption and transport.

Growing sites (buds, stem tips, root tips, newly formed leaves) need boron, and it also promotes flowering, fruiting, and seeding. Also, it helps regulate hormones and is involved in protein synthesis, among many uses.

Drought, cold root zone, extreme pH, waterlogged soils, excessive rain or irrigation, salinity, high humidity, and coarse-textured or sandy soils are common reasons for boron deficiency. Also, overfarming, low organic matter, and using water or fertilizer boron low may be reasons.

Signs of boron deficiency will first affect vegetative terminal points (shoots, buds, and expanding leaves), root tips, and reproductive sites (flowering and fruiting).

Common symptoms that your plants need boron include stunted growth, death of growth tips or terminal buds, and fewer and smaller fruits. Also, newly growing leaves may be thickened, curled, hardened, wrinkled, or have twisted tips.

Conduct soil and plant tissue tests

Before applying any boron fertilizer, submit your soil and plant tissue to laboratories for tests. Results from these tests will help to determine the level of deficiency accurately and, consequently, the application rate.

Usually, soils with less than 0.5 ppm of hot water-extractable boron and plant tissue with less than 20 ppm are deficient. However, this depends on plant requirements and tolerance/sensitivity. For instance, alfalfa and canola require more and can withstand soils with higher boron concentrations than barley.

What are the usual boron application rates?

The boron application rate will depend on plant sensitivity, soil texture/type, deficiency level, soil status, and application method, among other factors.

In most cases, sensitive plants will need application rates of 0.5 to 1 lb. per acre, while low-sensitivity plants require as high as 3 lb. per acre. In coarse-textured soils, 0.4 lb. per acre may be enough, and levels above 1 lb. per acre are detrimental.

When to apply boron fertilizer

Plants need boron during their growing season. Therefore, you should apply it to your annuls and perennial crops during spring or fall, especially during the early bloom, reproductive stage, and fruiting. However, spring will be the best time if you have coarse or sandy soil.

How to apply boron fertilizer

There are many ways to use boron fertilizer, including foliar, fertigation, broadcasting, banding, etc. Common methods include the following:

1. Broadcasting

Broadcasting is the most common method, with a slightly higher application rate than foliar. Incorporate these fertilizers to full cultivation depth before seeding unless you do a surface broadcast, especially for hay crops. Please, don’t overlap areas, including on headlands.

2. Foliar boron spray application

The use of boron foliar sprays is another method that has been gaining popularity in the recent past. One big advantage of the foliar application is that you can reduce overall costs by mixing boron foliar products with pesticides, fungicides, and other chemicals.

It works best where the soil’s pH is high or plants cannot absorb boron via roots. However, for plants where boron is immobile, apply severally, including pre-bloom and early reproductive stage. For plants, it is mobile, you can apply it at any time, and it will provide for future developing tissue needs.

The typical boron foliar spray dosage/application rate is 0.25 to 0.5 lb. per acre, with higher concentrations increasing risks of leaf burns/injury. Some plants can tolerate up to 1 lb./acre. However, we recommend you go for several low-concentration applications as the overall requirement depends on plant requirements.

Also, quick evaporation during a hot clear day may result in salt scorching. Also, excessive uptake of foliar boron during cool, humid days characterized by low evaporation may cause toxicity/injury. However, if you use the right concentration, these issues are unlikely.

One concern when using other chemicals (fungicides, pesticides, and other chemicals) is that the pH rise will affect these chemicals. However, the breakdown is slow, and most will remain effective for several hours to days.

Also, there is no strong evidence to support such breakdown, and you can add a buffer like citric acid to help maintain favorable pH. However, be sure to follow the given instructions.

How much plants will take in depends on the boron thin film’s duration on the applied surface; early morning application when dew is present is ideal as the moisture helps nutrients pass to inner tissues.

Lastly, some of the foliar-applied boron will end up in the soil. So, regularly test the soil to avoid toxicity.

3. Banding

We don’t recommend boron banding or seed placing since these methods will result in localized concentrates, resulting in toxicity, especially for sensitive crops, unless you cultivate the soil before seeding. However, plants resistant to toxicity, like alfalfa and canola, can withstand banding if you apply the correct rates.

4. Side dressing

Side dressing with boron fertilizer is ok for people with sandy or highly draining soils or those low in organic matter.

5. Fertigation

Fertigation of the highly soluble boron fertilizer is an excellent method. It will help improve water-soluble boron in the soil.

Best boron fertilizers for plants

If you are interested in the best brands, some of the top ones to buy include the following:

1. Borax Solubor, Granubor, Fertibor and Zincubor

With over 150 years of experience, US Borax, part of Rio Tinto Group, is a global leader in borate supply, technology, and science, providing over 30% of the refined borates for various uses, including industrial and agricultural for their world-class boron mine in California, 100 miles NE of Los Angeles

Their top boron products you should consider using include the following:

a). Solubor® boron fertilizer

Solubor is an OMRI-listed, highly economical, quick liquid dispersing, highly concentrated (20.5% boron) liquid fertilizer that leaves minimal residue. It is, without a doubt, the number one choice of boron foliar application.

You can use it to make high-performance fertigation liquids or as part of nitrogen fertilizer applications. Also, it is ideal for hydroponics or multi-element soluble powder for foliar application. 

b). Granubor®

If you need a 100% water soluble, dry granulated 15% boron fertilizer perfect for blending or alone use, look no further than Granubor®. This OMRI-listed product will ensure your crops meet boron needs during growing months.

c). Fertibor®

Fertibor® is a highly soluble, OMRI-listed, granular 15% boron fertilizer ideal for adding to liquid, suspension, or solid fertilizer. Also, you can apply it to the soil and mix it with growing media or compost, and is popular for various perennial crops, especially palm oil crops.

c). Solubor® Flow

Solubor® Flow is a liquid sodium borate microcrystal aqueous suspension with 10% boron that readily disperses and rapidly dissolves when added to water.

You can use it for foliar application, especially in young plants, hydroponics, or fertigation. Also, you can add urea ammonium nitrate and apply the mixture to the soil.

We find Solubor Flow a unique pick because of its compatibility with most plant protectants and the non-oily, non-viscous, and solvent-free formulation.

d). Zincubor® (zinc boron fertilizer)

Zincubor is a boron zinc fertilizer with a perfect zinc-to-boron ratio of 2:1, i.e., 29% zinc and 14.5% boron, intended to curb deficiencies of these two micronutrients often occur together.

Some of the use of Zincubor include a direct application as a raw material for suspension fertilizer, making fortified/compound material, or for micronutrient coating.

e). Anhybor®

With 20.8% boron, Anhybor is made via borax dehydration and fusion. This brand is specifically designed for fertilizer manufacturers. However, it is usable as an intermediate ingredient for direct application to the soil via fertilizer mixture.

2. OMEX Foliar Boron 11.0%

OMEX Foliar Boron is another excellent brand with 11% boron and 4.8% nitrogen. You can use it on root crops, cotton, vines, oil seeds, brassica, and other vegetables. All you need to do is to follow the provided mix rates for various crops.

This quality product is by OMEX, a UK company with a presence in the US, Canada, and Brazil. OMEX, a family-owned company incepted in 1976, focuses on liquid fertilizer (suspension, solution, and foliar), horticultural nutritional advisory, wastewater treatment, and Agrifluids.

You can trust their products as they are efficient and will achieve desired results. Just make you follow application and storage guidelines.

3. OrganiBOR® by Grochem and Omnia 

Made from Magnesium and calcium borate rock that naturally occurs only in Andes Argentina, OrganiBOR® is a slow boron release brand popular in New Zealand and Australia sold by Omnia and Grochem. It releases boron almost at the rate that plants need it.

A great thing about OrganiBor is that it is not as highly soluble as sodium borate, whose quick release can cause toxicity to plants necessitating smaller, often applications. Also, OrganiBOR will not quickly leach, meaning it will continuously provide your plant with boron for 1-3 years, depending on the crop, climate, and soil condition.

Lastly, OrganiBOR, a revolutionary BioGro Certified organic fertilizer, is perfect for any crop, including vegetables, shrubs, trees, vines, apples, grapes, avocadoes, and other fruits. However, since its slow release, OrganiBOR takes a little longer (4-8 weeks) to give visible results.

4. Foliar-Pak® Boron 7.0%

Foliar-Pak® Boron is a concentrated liquid boron made and guaranteed by ENP Investments, LLC., at their facility in Mendota, Illinois. This highly soluble boron-amino acid complex has 7.0% water-soluble nitrogen and 3.0% boron from boric acid.

You can use it on your gold course greens, tees, sports tuff, lawns, hanging and bedding plants, trees, and shrubs. Also, it is compatible with most pesticides and fertilizers and is applicable as foliar, or you can drench it in the soil.

Lastly, besides boron, Foliar Park also has superior-quality nutrient enhancers, Amino acids, specialty nutrients, and wetting agents.

5. WUXAL® Boron Plus 7.7%

If you need highly concentrated boron suspension for foliar application with nitrogen, phosphate, and other micronutrients (iron, copper, manganese, molybdenum, and zinc), look no further than WUXAL Boron Plus.

Since 1963, WUXAL®, a German brand, prides itself on offering premium foliar liquid/suspension fertilizers, biostimulants, and seed treatments. This German brand has a presence in over 70 countries worldwide.

Their boron foliar fertilizer penetrates more efficiently thanks to the phosphorus and nitrogen effect and has great buffering (at pH 6.5) to maximize nutrient absorption and use with pesticides. You can apply it to vegetables, viticulture, fruit, and arable crops/

We love it because it will improve drought stress for young crop plants and provide excellent adhesiveness and rain fastness. Also, it is usable with hard water up to 40° dH and will provide phosphate to your plants even during unfavorable conditions, like drought or cold spring season.

6. Plant Food Company, Inc. Liquid Boron 10%

You can trust liquid Boron 10% by Plant Food Company, Inc., a family-owned company that makes premium quality fertilizers, started by Edward Platz in 1946 in New Jersey. It has several other products, including tuff pigments, fungicides, micronutrients, bio-simulants, wetting agents, accessories, etc.

This boron liquid fertilizer is ideal for various vegetables, field crops, fruits, and nuts. You can apply it alone or mix it with most of their liquid fertilizers, pesticides, or micronutrients except Ag-Cal 10% Foliar Calcium.

Lastly, you can use foliar, broadcast, side dressing, solid set, or trickle irritation when applying it. However, for broadcast, don’t exceed a gallon/acre; for trickle and side dressing application, use (no more than 2 quarts per acre).

7. Active Boron™ 6.0%

Active Boron, with 2.5% total nitrogen and 6.0% actual boron, is perfect for ensuring your berries, grapes, fruit trees, vegetables, and fruit crops get enough or fixing any boron deficiencies. This foliar product by Active AgriScience Inc. is compatible with most fertilizers and pesticides.

Active AgriScience Inc. began operations in 2013 and works with top Canadian universities to ensure it provides superior quality, effective foliar plant nutrition, seed treatment, and nitrogen management product. Its headquarters is in Saskatoon, Canada, with distributors in Canada, the UK, Germany, and Australia.

8. Nano-chelated Boron fertilizer 9%

A good example of nano-chelated boron is the High-Tech Nano Chelated Boron Fertilizer 9% sold by Al Barea Al Amin Trading (Dubai). It is highly absorbable and water soluble; you can apply it on leaves (foliar) or in the soil.

It will help reverse some damage if you apply it early, and you can use it on trees including fruits trees (citrus, kiwifruits, stone and olive fruit), sugar beets, cotton, ornamental plants, vegetables, and other farm crops

9. Aspire Boron Fertilizer

Aspire is a revolutionary fertilizer with boron distributed throughout potassium chloride granules by The Mosaic Company. This fertilizer features Nutriform® technology with quick-release sodium borate and gradual calcium borate to ensure your plant has boron throughout the growing season.

The granular form ensures you can evenly distribute it, which traditional fertilizers struggle to achieve.

Tips to avoid boron toxicity

To avoid toxicity arising from boron application, do the following:

  • Use correct application rates depending on what soil analysis and tissue tests reveal, soil type, plant sensitivity, etc.
  • Apply at early stages in crop rotation to ensure the little residual effect on sensitive plants.
  • Beware of residual effects. The previous application may last up to 3-4 years, depending on application rate, soil texture/type, rainfall, and irrigation amounts. Most products have a lifespan of three years except for sandy or well-drained, irrigated soils.
  • Avoid planting grass crops like milo, fescue, or corn immediately after applying boron.
  • Always incorporate boron after application. However, you can still opt for no-till.