As with most weeds, mosses form in moist, bare areas of a garden. But unlike most weeds, moss requires expertise to remove. Thankfully, the chemicals used to kill mosses are completely garden safe and in most cases will improve a garden's overall foliage color. Even if moss treatments are applied, however, the moss will return without additional measures.
Dilute the moss killing product as directed on the package and mix in a 20-gallon pressurized spray can. Wash your hands after handling the solution to avoid chemical residues and, in this case, stains on your skin.
Spray a thin layer of the chemical on moss in late winter or early spring before it has had time to spread.
Rake moss out of the garden once it is dead. Avoid raking it across the entire garden to prevent spores from spreading.
Sow some groundcover seeds over the area that the moss covered. Some examples are herbs such as dill, mint or parsley or flowers such as lantana or alyssum.
Cover the seeds with garden soil and keep the ground moist until the seeds establish.