
Moss grows in poorly drained or damp, shaded, poorly fertilized situations or where over-grazing occurs. Major improvements in these individual management practices or combinations of these management practices will control the problem.
Ferrous sulfate or ferrous ammonium sulfate are two products usually used to control moss problems in field crops, turf and lawns. These products, when applied properly, will reduce the intensity of moss development, however they will not eliminate it. Please follow the application directions from the manufacturer. The real control of moss will come through a change of management practices applied to the problem area. Before applying any soil amendment, it is always a good idea to do soil nutrient testing.
If the area is wet, improve the drainage. If the vegetation vigor is low, improve the fertility of the area by applying adequate quantities of fertilizer and/or lime. Moss thrives in shady areas. Prune or thin low branches on trees if it can be done safely and as long as it is legal to do so. If undesirable vegetation is present, reseed with improved species such as tall fescue, perennial rye grass, white clover or orchard grass. For larger acreages, KCD’s Kasco EcoDrill no-till seeder may be an option to do some reseeding. KCD’s RhinoLimer drop spreader may be an option for spreading limestome or dolomite to raise the pH (reduce acidity).
Once the vegetation is established and growing well, do not over-graze it. Grazing in a rotational manner will help improve your desirable vegetation. Graze down to a 3 to 4-inch height and then move the animals to the next pasture in the rotation. Mowing after removing the livestock will help even out the remaining grass height and give the smaller vegetation a greater chance at competing. After mowing, allow the grass to grow to a 6 to 10-inch height before grazing again.
Vegetative competition is the best answer to moss control. If permanent forage management practices are not instituted to control moss development, moss suppressant chemicals will only provide temporary relief.

Senior Resource Specialist, Rural Land Stewardship
O: 425-282-1905 – C: 425-773-8097
Jay Mirro has served the people and resources of King County as a resource planner since 2000. He has visited thousands of farms and has written over 500 farm plans. Jay has practical and academic expertise on conservation practices and enjoys helping landowners meet their goals while protecting the environment — “saving the world, one farm at a time.” He grew up in rural New Jersey, working on horse and llama farms, and then studied Livestock and Range Management at the University of Idaho. Jay and his family own a 34-acre farm in Maple Valley. He looks forward to sharing with you what he has done around his farm on his next farm tour. When not working on his own or other farms, Jay enjoys remodeling his home, reading, travel, gardening hiking and helping his two boys grow up into young men.