Since You Asked…

Crops have a lot to say. TPS Lab’s Ask The Plant program is making sure growers hear.

Published online: May 02, 2018 Articles Tyrell Marchant, Editor
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This article appears as the cover feature in the May 2018 issue of Potato Grower.

Over the course of the last half-decade or so, there has been a growing movement among elite athletes to better understand how their individual bodies function when “healthy,” in an effort to avoid injury and ultimately lengthen athletic careers. Its practitioners have dubbed it “applied sports science.” The idea is that if an athlete—say, a basketball player who cuts to his left with 20 percent more force than to his right—can identify inefficient idiosyncrasies in his movement, he can decrease unnecessary wear and tear on a particular part of his body, thereby reducing the risk of injury.   

That same idea of seeking pre-injury prescription, rather than post-injury damage control and rehabilitation, is what drives the agronomic minds at the 80-year-old TPS Lab in Edinburg, Texas. Situated in South Texas in the heart of the Rio Grande Valley, TPS Lab has for 64 years administered its Ask The Plant program in growers’ fields by “listening” to crops’ faint whispers in advance of the occurrence of yield- and profit-robbing nutritional deficiencies.  

“By the time you see deficiencies,” says TPS Lab’s senior consultant and vice president of operations, Noel Garcia, CCA, “they’ve already been costing you yield and quality. We want to fix those problems before they get to that point.”

Ask The Plant begins with TPS Lab’s carbonic acid extraction soil tests. Most traditional tests, particularly in soils with a high pH, overestimate what nutrients are actually plant-available, Garcia says. Carbonic acid is naturally formed in the soil around the roots. It is only the carbonic acid and water-soluble nutrient compounds that the plant can absorb.     

“We’re mimicking the roots,” explains Garcia. “So regardless of the soil, whether the crop is growing in South Texas or in the Pacific Northwest or in Ireland, the test is accurate. It doesn’t matter; carbonic acid is formed the same way. The test calibrates very well back to plant uptake.”

But the soil test is only the season’s start of crop success in the Ask The Plant program. The real game changer is the regular plant sap and tissue tests throughout the season. “That’s where we really ‘ask the plant,’” says Garcia.

“While there are many labs that perform plant sap and tissue analyses, they typically use 60-year-old (or older) published standards for their interpretations and recommendations—if they give any specific recommendations, at all,” says Garcia. “The critical key to remarkable crop successes is timing—when and where to put how much of what. At the end of the day, all growers and consultants want to know is really only that.

“There have been many new discoveries in plant nutrition and a lot of new crop varieties introduced since the ’50s,” he adds. “Additionally, there are now more efficient fertilizer products available that go way beyond just N-P-K. Biological inoculants, amino acids and hormones can yield really dramatic results, especially when there is disease or nematode infestation, or physical damage, as by hail or sandstorms.”

Ask The Plant tests provide closed-loop feedback about a crop’s nutritional status. As Garcia points out, a potato plant’s nutritional requirements are changing all the time. Ask The Plant gives growers seven to 21 days to correct nutritional problems before crop performance is impacted for the season. Even accounting for the time it takes to ship samples to TPS Lab, Garcia says that time frame still leaves plenty of time for the grower to fix any potential problems.

Garcia recommends potato growers start taking plant tissue samples when plants reach eight to 10 inches in height, then continue weekly to the end of the season.  

“You have to stay on top of nutrition to keep the plants happy,” he says. “You can’t do that by doing a little test and some hope-for-the-best fertilization two or three times a year. If you want to maximize the capabilities of your potato crop, you’ve got to stay on it more aggressively.

“We need to micro-manage potato plant nutrition because there’s no guarantee that what we apply actually gets into the plant,” Garcia continues. “If we can micro-manage all nutrients in-season, we can alleviate the typical hidden hunger and chronic malnutrition of the plant, as well as many disease and insect pressures. Plants have the ability to resist these if they have the nutritional resources. That generally leads to higher yields, better quality and, sometimes, the reduction of input costs like water, fertilizers, fungicides and pesticides.”

In January, TPS Lab hosted its first-ever Spud School in Fort Hall, Idaho. Nearly 150 people, including manufacturers’ representatives, growers and field consultants from 13 U.S. states and four Canadian provinces attended to get an in-depth understanding of potato plant nutrition and hear growers and consultants tell about their experiences with the Ask The Plant program. According to surveys, most left impressed—so much so that TPS Lab will be offering Spud School 2019, a more advanced course in potato crop nutrition. 

“Every one of our tests is a custom test,” says Garcia. “They have to be for the grower to get outstanding crop performance.

“There’s no one, big silver bullet, but a lot of little ones.”


TPS Lab can be contacted at (956) 383-0739 or