Mosses are small, simple, non-flowering plants. They are typically low-growing and somewhat yellowish-green in color. They grow vigorously in the cool, moist weather of fall, winter, and spring, when lawn grasses are less able to compete. Moss in lawns generally results from low soil fertility, high soil acidity, heavy shade, improper watering practices, diseased grass, poorly drained soil, compacted soil, or any combination of these. Permanent moss control depends on eliminating conditions which favor moss growth.

Management Options

Non-Chemical Management

Maintain a vigorous, healthy lawn to prevent moss infestation.
Provide proper fertilization and irrigation.
Provide good soil drainage.
Power or hand raking to remove moss will aid in control.
Reduce shady conditions by pruning trees and shrubs.
A soil test may be necessary to aid in correcting soil fertility or acidity. Your county extension agent or WSU Master Gardeners can recommend soil testing laboratories in your area.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Apply once the moss is growing most actively. Follow label instructions.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

Lilly Miller Moss Out! Lawn Granules with 10% iron
Active ingredient: ferrous sulfate monohydrate | EPA reg no: 802-543
Scotts Turf Builder with Moss Control 23-0-3
Active ingredient: ferrous sulfate monohydrate | EPA reg no: 538-223
This list may not include all products registered for this use.

Images

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Caption: Moss Photo by: G. Stahnke
Caption: Moss: alive and dead Photo by: G. Stahnke

WSU Extension

Hortsense