Lawn Care and Maintenance

Authors: Kelly Nichols

Chelated iron is one of a limited number of active ingredients allowed for use in weed control in lawns in Montgomery County. Research trials were conducted from 2023 to 2025 near College Park, Maryland, to determine the efficacy of chelated iron (Fiesta®) on summer weeds. Various rates and application timings of the liquid and granular formulations were used. Higher rates and applications closer together (less than four weeks apart) are more effective for weeds such as white clover, large crabgrass, and dandelion. More than two applications throughout the year, including in late summer, may be needed to control dandelion and plantain, perennial weeds with more carbohydrate storage in their taproots. While chelated iron shows some efficacy and can have a place in a turf weed control program, cost and labor requirements should be weighed (e.g., spot spraying instead of broadcast applications), and cultural control practices should be continued. Author: Kelly Nichols; Title: Efficacy of Chelated Iron in Turf Weed Control (FS-2026-0806).