Foliar-Applied Liquid Micronutrients Win Hands-Down


May 2016

At Growth Products, we’ve long touted the many benefits of using high-quality liquid fertilizers instead of granulars. So it’s no surprise that a recent article in Florida Turf Digest (“Turfgrass nutrition: iron, manganese and magnesium” 1), which compared liquid vs. granular applications of those nutrients, grabbed my attention.

Some of the information was really surprising. One of the studies cited showed that more than 95 percent of granular iron applied to alkaline soils becomes insoluble within one hour of entering the soil solution. Because of iron’s rapid oxidation in alkaline soils, a mere 5 percent of granular iron is still available for plant uptake 60 minutes after its application to turf.

Similarly, another university study showed that nearly 50 percent of granular manganese becomes insoluble within one hour after application to alkaline soils. The remaining 50 percent stays somewhat soluble for three weeks.

The authors of the article – Dr. Travis Shaddox, Dr. J. Bryan Unruh, and Dr. Jason Kruse – concluded that foliar applications of Fe, Mn and Mg are more effective than granular applications. As they point out, foliar applications prevent the natural oxidation of these elements in soil, they result in greater uniformity of nutrient distribution on a sports field or crop, and they allow for rapid and direct uptake through a plants’ leaves.

Figure 1. Aerial photograph of Princess bermudagrass three weeks after applying iron. Each dark green rectangle received liquid iron sulfate. All other rectangles received granular iron sources or no iron. (Florida Turfgrass Association)

Winning Solutions

Growth Products is widely known for its technologically advanced liquid fertilizers. Many of its complete fertilizers – such as The Classic 18-3-6  and ProBalance 15-0-15 – have macronutrients plus micros. If you are looking for micros only, Growth Products also has an array to choose from.

One of my favorites is Micrel Total 5-0-0 , which contains 8 chelated micros (magnesium, sulfur, boron, manganese, molybdenum, zinc, and 6% iron). Chlorotic plants respond to a single application of Micrel Total within 48 hours with a deeper green. On bentgrass turf, Micrel Total gives near-instant gratification, improving the turf’s color within 24 hours, without provoking irritating flush growth. 

Micrel Total, which is non-phototoxic, can be applied throughout the growing season, and it boosts in disease resistance and stress tolerance. When it is sprayed along with a herbicide application, Micrel greatly reduces unsightly yellowing.

Another popular liquid micro product from Growth Products is Cal-Mag-Max 7-0-3 with 4% Calcium and 2% Magnesium . Calcium and magnesium are key components of chlorophyll, and are essential to plant health.

In ornamentals, a magnesium deficiency is easily recognizes by a plant’s interveinal chlorosis, in which the leaf veins remain green but the areas between the veins turns yellow. But in turf – and in fact in all situations – it’s best to pinpoint a magnesium or calcium deficiency by soil testing. When soil levels of these two elements are low, Cal-Mag-Max™ can be used as a stand-alone spray or can be added to any fertilizer spray solution. The result will be stronger turf that is better able to withstand foot traffic and other stress.

Give Us A Call

Independent research studies such as the ones discussed in the Florida Turf Digest article continue to show that foliar is the smart way to go. To learn about all of Growth Products liquid solutions – including its liquid micronutrients – you can read our product catalog online at www.growthproducts.com. Or better yet, give us a call. We’ll be glad to discuss your turf nutrition needs. We can help diagnose any current or potential problems, help with soil or tissue tests, and work with you to plan a nutrition program that suits your needs.

1 “Turfgrass nutrition: iron, manganese and magnesium,” Florida Turf Digest, March/April 2016, by Travis Shaddox, Ph.D., J. Bryan Unruh, Ph.D., and Jason Kruse, Ph. D.