Scarification: Remove loose moss in autumn, by scarification (vigorous raking). On small lawns this can be done by hand, raking out the moss with a spring-tine rake, but on larger lawns mechanical scarifiers can be hired.
MO Bacter: A non-chemical product called MO Bacter Organic Lawn Fertiliser claims good control of moss, as well as feeding the lawn. The added benefit is that the dead moss should break down in situ, negating the need for scarifying.
For moss control use a proprietary product (e.g. Vitax Green Up Mossfree), such as those based on ferrous sulphate (sulphate of iron) in spring or early autumn. When the moss blackens after two or three weeks use a spring-tine rake to remove it. The dead moss can be added to the compost heap. Although slow to rot in bulk, moss can be composted if well mixed with plenty (four times the volume of the moss) of other ingredients. Moss can be stored and added gradually as other ingredients become available. As moss is very widespread any spores that survive the composting process won’t add significantly to the risk of moss forming in the garden. Best practice is to avoid consigning moss to the green waste collection, and disposal by composting, or in extreme cases stacking or burial is recommended.
Mosskillers combined with a fertiliser (nitrogen, phosphorus or potassium, indicated by the abbreviations NPK) (e.g. Scotts Lawn Builder Lawn Food Plus Moss Control, Vitax Green Up Lawn Sand Moss Control or William Sinclair J. Arthur Bower's Autumn Lawn Food & Mosskiller) are beneficial where grass vigour is low.
Apply mosskillers either by hand or with a push-along spreader. Be careful not to apply lawn sand (ferrous sulphate mixed with a carrier) at too high a rate as this can blacken and kill the grass as well as the moss. Apply lawn mosskillers in fine weather. Some require watering after 48 hours if there has been no rain. Check pack for details.
Control with a mosskiller will only be temporary unless the conditions which allowed the moss to become established are improved.
New lawns: Good preparation should ensure moss control is rarely required on a new lawn. However, if the need does arise, double check the manufacturer's recommendations on the pack before applying. Many products should not be applied within the first six months or after a certain number of cuts.
Artificial lawns: Brinton's Patio Magic (containing benzalkonium chloride) will control moss on artificial turf. Keep artificial turf in good condition by regular brushing. Ensure water is not allowed to pool on the surface.
Note on ferrous sulphate: Although ferrous sulphate is widely offered as a fertiliser and soil acidifying agent, unless it is contained within a proprietary lawn mosskiller it is not approved for use as a pesticide and cannot be legally used to control moss. In addition, if it were to be applied as a mosskiller on lawns there is a high risk that it will blacken and potentially kill the grass - a problem seldom encountered with proprietary lawn mosskillers, especially those in pelleted forms, making them easy to apply evenly and accurately.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners - see sections 1d and 2a for lawn mosskillers)
Chemicals: using safely and effectively