Whether you consider yourself a lawn care expert or simply take pride in producing the best lawn in the neighborhood, you’ve likely thought about, or at the very least, heard of micronutrients for the grass or micronutrient fertilizers. Micronutrients got their name, not because they are any less important than other nutrients; they’re essential for your turf to complete its life cycle, but rather, due to the small amount in which they are utilized by your turf.
Some of the most widely used nutrients commonly found in micronutrient fertilizers include iron, manganese, and zinc. These micronutrients commonly exist in fertilizers as salts. In chemistry, a salt is simply a compound that consists of two ions, one positively charged and one negatively charged, which results in a compound of neutral charge. A common example of this is table salt which consists of a positively charged sodium (Na+) ion and a negatively charged chloride (Cl-) ion held together by an ionic bond. Existing in the form of salt means that these nutrients are both water-soluble and react very readily. So what does all this mean for micronutrient fertilizers and your soil?
Micronutrients in the soil
Well, let’s start with the soil. Well-aerated soils and soils with a high pH have plenty of oxygen (O2-) and hydroxide (OH-) ions, respectively. Keep this in mind and we’ll return that in a second. Like table salt dissolving in water, which involves the separation of the neutrally charged NaCl compound back into separate positively and negatively charged ions of Na+ and Cl-, the metal micronutrient, when dissolved in solution, exists as a positively charged ion. Remember the O2- and OH- present in the soil? The positively charged metal ion will react with these negatively charged ions and form compounds that are not readily available for plants to use, like oxides and hydroxides (e.g. FeO, Fe(OH)2). So does this mean that fertilizing our lawns grown on soils that contain oxygen and hydroxide (pretty much every soil) with these micronutrients is a complete waste? Not necessarily. These metal ions can be manufactured as complexes or complexed micronutrients. Complexed micronutrients are formulated to help keep the metal ion from reacting with things like oxygen and hydroxide in the soil, keeping them readily available to your turf. This is all done by combing the micronutrient with a complexing agent.
Complexing agents are forms of ligands. A complexing agent binds with a metal ion in a system through single or multiple sites from different atoms in the complex. They include things like lignosulfonates, gluconates, humates, and amino acids. They originate from natural products and are environmentally friendly. Their primary purpose is to bind to the metal ion and keep it from reacting with other ions in the soil. Depending on the soil pH and the effectiveness of the complexing agent, the micronutrient will ideally remain in a plant-available form long enough to be taken up by your lawn.
How should you add micronutrients to your lawn? Complexed micronutrients also work well for foliar fertilization of your lawn. Foliar applications of iron lignosulfonate, a complexed iron source, showed a great greening response in St. Augustinegrass and would likely do the same if your lawn were deficient in iron, as well. Foliar applications of micronutrients are a great way to bypass the soil and deliver the nutrient right to the leaves of your lawn. Foliar applications of micronutrient lawn fertilizers are made by applying nutrients in a liquid form directly to the leaves of the plant, where they can be put to immediate use. Check out our line of liquid micronutrients for lawn like Lawn Energizer 6-0-0 containing complexed iron, magnesium, and manganese, Darker Green contains a perfect dose of complexed iron and manganese, and our Micro Booster with complexed magnesium, iron, zinc, and manganese.
So what are the best micronutrients for your lawn? This depends on your soil, so you will want to obtain a soil test to be sure. At Simple Lawn Solutions, we’re here to help demystify the complexities of micronutrient fertilization, contact us today if you have any questions about how to know what micronutrients your lawn needs.