Notes on boron and Florida specialty crops.
In the field: Kozan, Adana, Turkey
Approximately 1 ton of İB-BOR, the Turkish-market product of VerdeBor®'s manufacturer, has been used by growers in the Kozan region of Adana, Turkey, on citrus, persimmon, olive, pomegranate, and grain crops. To date, no adverse effects have been reported.
The Role of Boron in Citrus, Strawberry, and Blueberry Production
Boron is one of the essential micronutrients plants need in small but critical amounts. While required in far smaller quantities than nitrogen, phosphorus, or potassium, boron plays a specific and non-substitutable role in plant development — particularly during flowering and fruit set.
Why Boron Matters
Boron supports several key physiological processes in plants:
- Flower and pollen development — boron is involved in pollen tube growth, which directly affects fruit set.
- Cell wall formation — it contributes to the structural integrity of new plant tissue.
- Sugar transport — boron assists in moving sugars produced during photosynthesis to where the plant needs them, including developing fruit.
Because boron is not very mobile within the plant, a steady, adequate supply — rather than a single large application — tends to support more consistent results across a growing season.
Boron in Florida's Specialty Crops
Florida's sandy, well-drained soils often have limited micronutrient retention, which can make consistent boron availability a challenge for growers. This is particularly relevant for:
- Citrus — boron deficiency in citrus has been associated with issues in fruit set and internal fruit quality.
- Strawberries — as a crop with a relatively short but intensive fruiting period, strawberries benefit from stable micronutrient availability during flowering.
- Blueberries — grown in Florida's acidic, sandy soils, blueberries have their own specific nutrient uptake patterns that growers monitor closely.
Testing Before Applying
As with any fertility program, a soil or tissue test is the most reliable way to confirm whether a boron deficiency is present before applying any boron-containing product. Over-application of boron can be as detrimental as deficiency, since the margin between adequate and excessive boron levels is narrower than for most other nutrients.
About VerdeBor®
VerdeBor® is a liquid boron fertilizer, distributed under Florida Fertilizer License No. F003942 issued by the Florida Department of Agriculture and Consumer Services (FDACS) to VERDEBOR LLC, with a guaranteed analysis of 2.10% boron (B), derived from boric acid. VerdeBor® is intended for professional and agricultural use only. Always conduct a soil or tissue test to confirm boron deficiency before application, and follow label directions for application rates.
Liquid vs. Granular Micronutrients: What Florida's Soils Change
Growers choosing between liquid and granular fertilizer formulations often find that the right answer depends less on the nutrient itself and more on the soil it's going into. In Florida, soil texture plays an outsized role in that decision.
Florida's Soil Profile
Much of Florida's agricultural land sits on sandy, well-drained soils with relatively low organic matter and cation exchange capacity. These soils drain quickly — which is good for preventing waterlogging, but it also means nutrients, especially mobile ones, can move past the root zone before a plant has a chance to take them up.
Where Liquid Formulations Fit
Liquid fertilizers are fully dissolved before application, which has a few practical implications:
- Immediate availability — there's no dissolution step in the soil, so nutrients are accessible to roots (or leaf surfaces, in foliar applications) right away.
- Even distribution — liquids spread uniformly through irrigation or spray equipment, reducing the risk of uneven granule placement.
- Foliar option — some nutrients, boron included, can be applied directly to foliage when a fast, targeted correction is needed, which isn't possible with granular products.
Where Granular Formulations Fit
Granular fertilizers release more gradually as they dissolve with rainfall or irrigation, which can be an advantage for nutrients you want to make available over a longer window, or in situations where fewer applications per season is a priority for labor and logistics reasons.
The Practical Middle Ground
Many Florida growers use both: granular materials for baseline soil fertility, and liquid micronutrients — often applied via fertigation or foliar spray — to correct specific, fast-onset deficiencies that show up during a critical growth stage like flowering or fruit set.
Boron is a common example of this pattern. Because boron deficiency symptoms can appear quickly during bloom, and because boron doesn't stay in sandy soil profiles for long, a liquid application timed to the crop's flowering window is often more practical than relying solely on a granular program applied earlier in the season.
Testing Guides the Decision
Regardless of formulation, a soil or tissue test remains the starting point for any nutrient program. It tells you not just whether a nutrient is deficient, but how urgently it needs correcting — which is often the deciding factor between a granular baseline application and a liquid, in-season correction.
Why a Soil or Tissue Test Should Come Before Any Micronutrient Program
It's tempting to treat visible symptoms — pale leaves, poor fruit set, stunted growth — as a signal to apply more of whatever nutrient seems most likely to be missing. But for micronutrients like boron, guessing can cost more than it saves.
The Narrow Margin Problem
Unlike macronutrients such as nitrogen, where the range between "not enough" and "too much" is relatively wide, boron has a much narrower safe range. Too little boron causes poor flowering and fruit set. Too much can cause leaf burn and toxicity symptoms that look surprisingly similar to deficiency at first glance. Without a test, it's genuinely difficult to tell which direction a problem is coming from just by looking at a plant.
What a Soil Test Tells You
A soil test measures what's available in the root zone at the time of sampling. For a nutrient like boron that moves easily through sandy, well-drained soils, this snapshot can change meaningfully between seasons — which is part of why boron programs are often re-evaluated more frequently than programs for less mobile nutrients.
What a Tissue Test Adds
A soil test shows what's present in the soil; a tissue test shows what the plant has actually taken up. The two don't always agree — a nutrient can be present in the soil but unavailable to the plant due to pH, competing nutrients, or root conditions. For a fuller picture, many growers use both, particularly ahead of a critical growth stage like flowering.
Timing Matters
For boron specifically, testing ahead of bloom is common practice, since that's when boron's role in pollen tube growth and fruit set becomes most relevant. A correction applied after flowering symptoms are already visible is working against a narrower window than one applied proactively.
Where This Fits Into a Fertility Program
Testing doesn't replace a fertility program — it directs it. Knowing the actual boron status of a field before applying a liquid or granular boron product means applying the right amount, at the right time, rather than treating every field the same way regardless of its actual nutrient status.