Back to Info Sheets	Control of Moss in the Lawn   Copied from Department of Forestry and Agriculture. Government of Newfoundland and Labrador.  By Ross Traverse, Crops Co-ordinator.  729-6821 Moss is perhaps the most common weed of neglected turf in high rainfall areas.  Most plants have a tremendous capacity for reproduction.  They produce immense numbers of spores, each of which gives rise to a new  moss plant if provided with a suitable moist environment.  However, moss plants cannot compete with vigorous, healthy turfgrass.  It is only when the grass is weakened by unfavourable growing conditions that moss becomes established and takes over if the process is not arrested.  Conditions which contribute to a problem with moss include such factors as poor aeration, poor drainage, low fertility, high acidity and heavy shade.  These are all conditions which reduce grass vigour but encourage growth and development of mosses. To control moss the approach must include chemical treatment to eliminate the moss already established and cultural treatments to prevent re-colonization.  Chemical treatment is only temporarily effective if growing conditions for grass are not improved.   CHEMICAL CONTROL: Use one of the following: *       Apply ammonium sulphate (21-0-0) at the rate of about 10 lbs / 1000 sq  ft.  Do not water but allow the fertilizer to burn out the moss.  The grass will burn also but will recover in a few weeks.  Single super-phosphate (0-20-0) at about 6 lbs / 1000 sq ft. serves a similar purpose and is preferable if it is to be followed by over-seeding. *  Commercial moss killer applied according to label directions.  Most of these contain ferrous sulphate and ammonium sulphate.          About 2 weeks after treatment, remove dead moss by raking.  Apply lime if soil is acid (less than pH 6).  If grass is thin or bare patches are present, over-seed with an appropriate grass mixture, one with shade tolerant grass (fescue) if shade is a problem, such as the Greenfast Shade Nook grass seed that is insect and disease resistant.   CULTURAL CONTROL: *   Improve surface drainage.  In addition, subsurface drainage tiles may need to be installed if water remains in puddles at the surface after irrigation or after a rain. *   Remove thatch.  Buildup of dead organic matter forms a spongy layer that increases water retention and reduces grass vigour.  Thatch can be removed by vigorous raking or the use of a vertical mower. *    Reduce compaction and increase aeration by spiking, slicing or aerifying with a mechanical aerator. * Reduce shade if possible.  Judicious pruning of trees and shrubs can make a difference to density of shade. *    Have your soil tested using a Rapitest Soil Kit available at Murrays.  Apply limestone if your soil is acid, at a rate of 100 Lbs per 1000 sq. ft.. This application may be halved if you are liming in the spring and fall. *     Take care not to over-water.  Irrigation may be necessary in dry periods to sustain grass vigour , but excessive water will have the reverse effect. *     Improve grass vigour by use of  a balanced fertility program. *     Take care in mowing.  Mow frequently enough to remove not more than 1/3 of the top growth at mow time.  Mow at a height appropriate for the grass species (one to two  inches for fescues and bluegrass).  Mowing too closely reduces grass vigour and eventually results in thinning of grass stand with consequent invasion by weeds including mosses.ahlias are tender bulbs which need to be stored indoors over winter.  They are available in a variety of colours, forms, and sizes.   Vol 99 no 45
© Murray's Garden and Horticultural Services Last updated: March 8, 2008