Moss Control

Tim Garceau's Moss Control Program

Dialogue Regarding Moss Problem



Iron Summary

Controlling Moss in Putting Greens, Tom Cook, M.S., Brian McDonald and Kathy Merrifield, M/S., Orogon State University

Normal rates of iron for turf color enhancement are ~0.03 lb. iron / 1000 sq. ft.

Under cool wet conditions 0.15 to 0.20 lb. iron / 1000 sq. ft. controlled moss marginally (90 % kill) without injury or blackening of Providence creeping bentgrass. Turf is exceptionally dark green during treatment.

Ferric sulfate is more effective at killing moss than ferrous sulfate (Fe2SO4: 7H2O as a crystalline solid, Molecular weight = 278) Both require 5 - 7 treatments at 2 week intervals.

Chemistry Note: Ferric = Fe+++, ferrous = Fe++. Ferrous sulfate is Fe2SO4: 7H2O when as a crystalline solid, Molecular weight = 278)

Moss Control Research at Cornell University, Summary of 2002 Research, Frank S. Rossi, Ph.D. Discusses copper hydroxide based materials such as Kocide and Junction.
Moss Control in Putting Greens, Tom Cook, OSU Horticulture Dept., Corvallis, OR

Specific treatments included the following:

1) Iron from Ferrous Sulfate (heptahydrate) 0.2-lb Fe / 1000 sq ft / application

2) Iron from Ferrous Sulfate (heptahydrate) 0.4-lb Fe / 1000 sq ft / application

3) Iron from Ferrous Sulfate (heptahydrate) 0.6-lb Fe / 1000 sq ft / application

Initial applications demonstrated color responses from Iron Sulfate.....

After 5 repeats.....Iron Sulfate.....had no apparent effect on plot density.

Iron turned moss blackish brown eventually killing it apparently completely.

By the end of the treatment period, no moss could be detected in any plots receiving..... Iron.......

Moss Control New Products and Strategies, Peter Landschoot, Ph.D., Joshua Cook, And Bradley Park, USGA Greens Section Record,


The summer trials included three iron sulfate treatments (0.2, 0.4, and 0.6 lb. iron/1,000 sq. ft.)

Treatments that were effective in controlling moss included iron sulfate.... The two highest rates of iron sulfate (0.4 and 0.6 lb. iron/1,000 sq. ft.) provided 90-95% moss control but caused unacceptable injury to the turf.

The lowest rate of iron sulfate (0.2 lb. iron/1,000 sq. ft.) provided 75% control of moss and caused only slight blackening, but no turf thinning. The black turf color diminished within two to three mowings.


Treatments were applied every two weeks for a total of five applications. Treatments included iron sulfate (0.2 lb. iron/1,000 sq. ft.)....

Results: The iron sulfate treatment (0.2 lb. iron/1,000 sq. ft.) provided about 45% moss control, with no serious injury.


Options for Chemical Control of Moss in Putting Greens, Dr. Peter Landschoot and Mr. Joshua Cook, Dept. of Crop and Soil Sciences, Penn State Iron sulfate:

Has been used to control moss in putting greens for decades. Studies at Penn State showed that iron sulfate applied at 0.15 to 0.2 lb iron in 2 gallons water/1000 ft2 on 14 day intervals (4 to 7 applications) provides good moss control.

Can be applied at any time during the growing season, but moss control and turf recovery is better during periods of moderate temperatures (50 to 80oF).

Produces a noticeable, but temporary black color on moss and turf. When the black color dissipates, a pleasing green up of the turf occurs.

Is not labeled for moss control in turf.

Controlling Moss in Creeping
Bentgrass Putting Greens
, Brian McDonald*, Alexander Prideaux**, and Tom Cook, Horticulture Department
Oregon State University
Corvallis, Oregon

Optimum rates & number of treatments:

Ferrous and Ferric Sulfate - 0.2 lb Fe/1000 applied 5- 7 times at two-week intervals.

Work has been done between October and late May under cool weather conditions. Experience with iron products at high rates in hot weather indicates turf injury is likely.

Typical Iron application rates for moss control (0.1-0.2 lb Fe/1000/application) turn turf very dark green during the treatment period.