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The Basics of Iron Application for Turfgrass


Ensure your customers’ turfgrass remains healthy and vibrant with these tips.

May 23, 2024

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The Basics of Iron

Understanding the fundamentals of iron application is essential for maintaining healthy and vibrant turfgrass. Iron, available in liquid or granule form, plays a vital role in promoting chlorophyll production and conducting photosynthesis, thereby energizing the grass. 

Iron can be chelated or nonchelated. Chelated iron sources are preferred as they enhance iron availability for uptake by turfgrass roots and extend solubility, particularly in high pH soils. Products like chelated 12-0-0, 4-4-5, Mn High Combo, and micro-mix contain chelated micronutrients, providing an optimal iron source for grass. 


Understanding Iron’s Role

Iron acts as a multivitamin for grass, providing the energy needed for chlorophyll production and facilitating photosynthesis. Although iron is not the sole nutrient required for growth, its application enhances the color of turf grass, making it more appealing to customers. 


Timing and Frequency of Application

For cool-season grasses, iron fertilization is most effective during periods of high or low soil temperatures, especially in soils with high pH, calcium, or phosphorus levels. Warm-season grasses respond well to iron fertilization in late summer and early autumn when soil temperatures naturally decrease. Applying iron once per season to every two weeks is most conducive to turf growth, and low dosage and more frequent applications are ideal to reduce runoff and enhance absorption. Often, iron applications can be combined with fungicide treatments. 


Application Methods

Iron is typically applied to turfgrass foliage through spraying, although granule application has also been found to be highly effective. Heavier rates are often necessary for nonchelated iron applied with dry fertilizers, as oxidation may render it less available to the plant. Frequent mowing increases the need for more frequent iron application, while applying iron during periods of stress maximizes absorption and minimizes runoff. Additionally, applying iron during hot summers and cold autumns can enhance the turf’s vibrancy and resistance to desiccation. 


Avoiding Overapplication 

Moderation is key when applying iron to turfgrass. Excessive iron can be mowed off since it primarily accumulates in the newest portion of the blade. Normally, 1 to 2 pounds/acre (1.1 to 2.2 kilograms/hectare) of iron per application is sufficient, with higher rates beneficial in specific conditions. 


Soil Test Limitations

Although soil tests indicate the presence of iron in the ground, it doesn’t guarantee accessibility to plants. Factors such as high pH, phosphorus, or calcium content, common in sandy soils, can restrict iron uptake. Adding Iron even when soil tests show sufficient levels ensures that plants can effectively absorb and utilize this essential nutrient. 


Get Started with SiteOne

SiteOne associates are available to answer any questions you may have regarding iron product selection or application. Visit a branch near you or SiteOne.com to get started. 

For more information about turf care, visit our Learn section

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