How to avoid a mossy lawn;
Moss in your lawn is generally a result of poor growing conditions such as low fertility, compaction, over-acidity, poor drainage and / or excessive shade.
Listed below are a number of causes & solutions to some common problems;
Chemical control;
Circa Week 20; use a moss control based on ferrous sulphate (sulphate of iron).
Note; This product is often a constituent part of a spring lawn feed often referred to as 'Weed & Feed' or 'Spring lawn feed with added moss killer'.
So if you are planning on feeding your lawn, consider using such a product, and follow the application method written on the packaging.
Otherwise use the specific moss killer as per the manufacturers instructions.
Once treated, the moss dies and blackens.
The blackened moss can be allowed to decompose naturally, but it's better to rake it out and remove it.
Treated areas should be scarified two weeks after application of moss control.
Non-Chemical control;
This can be done by hand which extremely hard work or can be done mechanically.
By hand; use a multi-tined rake to scrape the moss off the lawn surface.
Where large areas require treatment it is advisable to hire a machine suited to the purpose.
Note; Providing the debris removed hasn’t been treated with a weed/moss killer it can be composted on the compost heap.
On completion you may find areas of the lawn devoid of grass so sow a suitable grass seed to rectify the situation.
In the remaining areas feed your lawn with a proprietary lawn feed suited to the season it is applied.
For the remainder of the season do not mow the grass too short.
By leaving longer, strong growing grass, you leave less space for moss to become established.
Impoverished soil;
Moss can thrive on poor soil as it needs less nutrients than grass.
To remedy this, apply a lawn or general fertiliser in the spring or summer. See note above!
Do not apply a high nitrogen fertiliser in late autumn, as this will encourage lush grass growth that may be vulnerable to frost and diseases.
Poor drainage;
Symptoms are; after rain, a poorly drained lawn will remain wet for longer,thus providing ideal conditions for moss to thrive in.
Type of soil can also be a major factor; e.g. heavy clay.
Poor drainage can also be caused by surface compaction brought about by children playing on children playing on it.
Moss needs constant high levels of dampness to reproduce and thrive, whereas lawn grasses wont tolerate such conditions.
Drainage can be improved by using a hollow-tined aerator which is pushed into the lawn at closely spaced intervals, resulting in cores of compacted soil being withdrawn.
Pour sharp sand or grit into these holes to produce drainage channels.
Use a lawn rake to remove the thatch of dead grass and moss.
Repeat this procedure every spring until conditions improve.
Note; this task is best not done in summer when the underlying soil can be rock hard.
Soil too acid;
Some kinds of moss prefer an acid soil, as do some of the finer lawn grasses.
Check the soil pH, and apply ground chalk or ground limestone or an alkaline fertiliser such as Nitro-chalk.
Do not overdo it or you may encourage weeds and grass diseases.
Compacted or badly aerated soil;
Grass takes in air, water and nutrients through its roots, so to remain healthy, it needs a good soil structure, whereas, moss roots are merely for anchorage, so it can tolerate compacted soil.
Spike the lawn to increase aeration and don't use a heavy roller.
Top-dressing with a mixture of sand, peat and loam will improve the surface structure after spiking.
Grass kept too long;
Lawns made of coarser grasses may be cut long 25mm (1”) or more, this provides ideal conditions for trailing types of moss.
Reduce the cutting height of your mower, and mow more frequently.
Finer lawn grasses are more suited to close mowing.
Grass kept too short;
Finer lawn grasses are usually cut very short and this encourages cushion-forming mosses, 'scalping' will damage the grass and allow moss to spread.
Use a cutting height of 13 to 20mm for finer grasses.
Too much shade;
Mosses need less light than grasses and the damp conditions associated with shade also suits them.
Prune overhanging trees and shrubs and remove tall hedges.
Too many weeds or pests;
Weeds compete with grass, pest damage the roots, so anything that weakens the grass will give moss a chance to spread.
Use lawn sand or a lawn weed killer to keep weeds at bay or a soil insecticide for pests.
Do not walk on lawns when they are frozen.