Iron is a micronutrient that is required for biosynthesis of chlorophyll. It is also important in reactions within the chloroplast. Due to its role in chlorophyll it can be applied to get a greening effect of the turf. Iron is most readily available to the plant under acidic conditions. As pH increases iron can become less available, requiring foliar or supplemental applications.
Although iron tends to be less available at a higher pH, foliar applications of iron when soil iron levels are high will induce a response. Although the response is not as dramatic as might be found on cool season turfgrasses, it is still noticeable.
Iron applications to couchgrass have been shown to reduce color loss during temperature stress. Iron can also promote green-up after a stress period.
The take home message is for extending greening or inducing a quicker green-up on couchgrass foliar applications are effective even if the iron levels in the soil are adequate regardless of pH.
