Minding Micronutrients: Elements That Can Make or Break Your Crop

Micronutrients are typically measured in ounces, not tons. But these small elements play an outsized role in your crop’s success. And as more growers sharpen their focus on plant nutrition and its role in plant health, these secondary elements are moving from an afterthought to a front-line tool in crop production.

That’s good news — and also a potential landmine.

Micronutrients are essential, but a little goes a long way,” says Kaan Kurtural, Senior Agronomy Information Technology Manager at Wilbur-Ellis. “It’s not uncommon for toxicity to show up if application rates aren’t precisely calculated.”

The challenge? Unlike macronutrients like nitrogen or potassium, micronutrients — boron, zinc, iron, copper, and others — don’t follow a one-size-fits-all script. Their availability, mobility, and effectiveness are closely tied to your soil pH, organic matter, and even your application method.

Why It Matters

Growers across the country are incorporating micronutrients into their programs. Many, like California’s Taylor Farms, have seen striking yield and quality improvements from what Agronomy Manager Kim Horton called “a few little tweaks.”

But the margin between helpful and harmful is narrow.

“Without enough boron and zinc, flowering won’t happen. And without flowering, you don’t have a crop,” Kurtural says.

Kurtural recommends a tissue test to confirm deficiencies, rather than relying on traditional soil tests.

“Soil tests are great for pH, EC, and major nutrients,” he says. “But micronutrients like boron or zinc? They’re much more accurately measured in plant tissue.”

As for sap tests? Kurtural is cautious.

“Everyone’s selling a sap test right now. But we don’t know what the values mean,” he says. “We can’t rite a recommendation from it.”

Signs of Trouble — and How to Avoid It

Micronutrient toxicity typically shows up too late to reverse. Symptoms can vary by element, but often appear as leaf bronzing, curling, or distorted shoot growth.

“The most common cause is an application error,” Kurtural says. “Not necessarily the product itself, but a miscalculation of the rate, especially with liquid formulations. These are potent products.”

Most micronutrient formulations contain only 5% to 6% of the target metal. That’s deliberate — it’s designed to reduce risk. But only if applied with precision.

“There’s no real luxury zone with micros. They’re either deficient, optimal, or in trouble,” he says.

To stay in that optimal zone, Kurtural recommends a two-part strategy: combine soil and tissue tests, and lean on experienced PCAs or CCAs to write conservative prescriptions.

For more on managing micronutrients for optimal plant health, click here to continue reading the full article as part of our special report on Plant Health.

In addition, check out the previous reports in Meister’s Global Insight Series covering a range of topics from Irrigation Innovations to Agricultural Technology.