3 Ways to Make the Most of Your In-Season Boron Application

“When we’re talking about micronutrients, boron often doesn’t get the attention it deserves,” said Sara Beasley, sales manager at Koch Agronomic Services (KAS). “But if you don’t have enough boron available when the crop needs it most, yield will suffer, no matter how well you manage the rest of your fertility plan.”

In corn, boron plays a key role in the structural components of plants and various plant processes, including cell wall formation, cell division and the movement of sugars and nutrients within the plant. But the most significant role boron plays happens during pollination, where it supports reproductive growth in tassels, silks and ears by aiding pollen development, pollen tube formation and successful fertilization. 

“Boron deficiency is a major concern for growers because of its role in pollination and grain fill. If we miss that window, there’s no way to get it back — even a short-term deficiency during pollination can lead to stunted ears, kernel abortion and tip back,” said Cody Hornaday, technical agronomist with Koch Agronomic Services (KAS). “That’s why it’s so important for growers to prioritize boron in their nutrient management plans.” 

Unlike macronutrient deficiencies, which often present visible symptoms early on, boron deficiencies tend to fly under the radar, only revealing themselves when it’s too late to correct the issue. Often, the first signs show up during pollination, when poor fertilization leads to stunted ears, kernel abortion or tip back that Hornaday mentioned. This concept aligns with Liebig’s Law of the Minimum, which describes that crop performance is limited by the nutrient in shortest supply, even if all others are sufficient. In many cases, boron may be that limiting factor, quietly capping yield potential until it's addressed.

To maximize yield potential, it’s about how, when and what source of boron you apply. These three strategies can help you get the most from your in-season boron application:

1. Time it right for maximum uptake: 

The reproductive stage is when corn needs boron the most, but it’s also when deficiencies are most likely to appear. Boron isn’t mobile within the plant, so if it’s not available in the soil when the crop needs it, the plant can’t pull it from older tissues for new growth. 

On top of that, boron is highly mobile in the soil, meaning it can leach out of the root zone with heavy rainfall events. Applying it too early in the season could mean it’s no longer available when uptake begins.

In corn, boron demand increases rapidly starting around V10 to V12 and remains critical through R1–R2. To get ahead of that spike, plan to apply boron between V4 and V10, with V4–V6 offering the best opportunity for the nutrient to be available in the root zone, reducing early-season loss risk. 

“We know corn’s demand for boron increases as it approaches pollination,” said Beasley. “By applying boron ahead of that window, you’re setting the crop up with what it needs before potential pollination stress kicks in.”

2. Pair boron with your nitrogen application: 

In-season nitrogen applications are a common and necessary part of corn fertility programs, and they present a great opportunity to deliver boron at the same time. Boron and nitrogen share similar uptake windows, so combining them in a single pass is both convenient and efficient.

While you're already making that nitrogen application, it's also worth considering a nitrogen stabilizer to protect against potential losses. Regardless of timing, nitrogen is vulnerable to volatilization, leaching and denitrification which can significantly impact both yield and return on investment. As Hornaday explained, ammonia volatilization alone can account for up to 40% of nitrogen loss when urea or UAN is surface-applied without proper incorporation.

Using a stabilizer like ANVOL™ during that same application can help safeguard your nitrogen investment and support season-long crop performance.

This approach helps growers stay efficient while giving their crop access to the nutrients it needs, when it needs them most.

3. Choose the right boron source for your operation:

The effectiveness of a boron application depends not just on timing, but on how well it's distributed across the field. Traditional granular boron can be inconsistent — some plants get too much, others too little or none at all.

That’s where WOLF TRAX™ Dry Dispersible Powder (DDP™) stands out. Its patented EvenCoat Technology, coats each granule of dry fertilizer, ensuring even boron distribution with every pass.

“With WOLF TRAX Boron DDP, you’re not relying on one big boron granule every 10 feet,” said Hornaday. “Instead, you get a more consistent application, which means more plants have access to the nutrient at the root zone when they need it.”

Hornaday explains that when you’re trying to apply a half-pound of boron per acre using a 10% borate source, that only amounts to five pounds of product which is far too little for consistent spread. But when WOLF TRAX is blended with a nitrogen carrier like urea, the boron is evenly distributed throughout the field.

“The even coating of boron around each fertilizer granule means better dispersion,” explained Hornaday. “You’re setting up each plant to access the nutrient instead of relying on a few scattered pellets.”

Set the stage for stronger pollination and better yields

As crops approach their most critical growth stages, every pass across the field becomes an opportunity to do more. Applying boron early, and pairing it with your nitrogen application protected by a stabilizer like ANVOL, helps make sure your crop has access to the nutrients it needs for successful pollination and grain fill. Choosing a source like WOLF TRAX DDP, which delivers even distribution across the field, adds even more value to that pass. With the right timing, products and strategy, you can maximize the value of every pass across the field.