Moss

The causes of moss in lawns & turf

Moss can invade almost any type of lawn, but it is more common in neglected lawns, where the grass has been allowed to become thin and weak.

Moss is most troublesome in the spring time. This is because grass does not grow during the winter months therefore with no competition from the grass, moss can easily invade any thin or bare areas on the lawn.

However by keeping the lawn in a healthy condition you can help prevent the conditions that encourage moss to invade. The conditions that moss favours are as follows:

• Poor surface drainage - this encourages fern and tufted type mosses.
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• Lack of fertility or nutrients - Any lawn low in essential nutrients will be thin and weak and open to moss invasion.
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• Acid soil conditions - Soils with a low pH encourage moss.
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• Shaded lawns - lawns which lack light tend to have poor grass coverage which leaves it open to moss invasion.
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• Mowing lawns too close - Mowing to closely weakens the sward resulting in thin grass coverage.
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• Drought - Lack of irrigation during drought conditions causes to grass coverage to suffer and moss can invade.

Prevention & control of moss in lawns & turf

Moss is one of the most frustrating lawn problems in the spring time, however with the correct management program most of these problems can be avoided.

Take care when mowing the lawn not to shave the grass down too short especially at the end of the growing season. The most effective way to stop moss invasion is to maintain a thick healthy lawn

If for whatever reason moss does become a problem there a couple of ways to control it, these are as follows.

• There are numerous products on the market available for the control of moss. Most of these moss control products contain sulphate of iron.
  
  The use of a product called lawn sand is the traditional way of controlling moss in lawns. Lawn sand contains three ingredients sulphate of ammonia, sulphate of iron and sand (sand is used as a carrier). The sulphate of iron kills the moss and this ingredient can also be applied on its own. The sulphate of ammonia is a nitrogen based fertiliser which will help with recovery by encouraging growth. The ideal time for an application of lawn sand is in the spring time when the grass is starting to show signs of growth after the winter months.
  
  Other products available as both liquid and granular formulations are also available for the control of moss. Most of these products will contain sulphate of iron plus some nitrogen to aid recovery. There are many of these products available on the market available from most garden centers. It is important to follow the manufactures recommendations when applying any product used for moss control.
  
  Please visit our Sulphate of Iron page for more info on moss control.
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• The other control method is to use a chemical moss killer containing the ingredient DICHLOROPHEN. This product gives a longer lasting kill than lawn sand and is usually applied through a sprayer in liquid form.

Lawn sand and sulphate of iron are applied with a spreader, these products are very light and powdery so it is best to avoid windy conditions. Both lawn sand and sulphate of iron will need watering in after application.

Sulphate of iron can also be mixed with hot water into a solution and sprayed onto the lawn via a sprayer. It is important to mix it thoroughly to prevent the sprayer becoming blocked.

Timing of moss control

Removal of moss and aftercare

About 10 - 14 days after the moss treatment was applied, the moss can be raked out of the lawn. Use either a powered lawn rake or scarifier or a hand rake depending on the area.

Once the moss has been removed and cleared away you can over seed and top dress the bare areas to help speed up recovery if necessary. Applying a nitrogen based fertiliser afterwards will help with recovery, however many moss killer products now contain a fertiliser for this purpose.

To prevent any future problems keep your lawn in a healthy condition by correcting the causes of moss as outlined above because it will return if the conditions are favourable. Light applications of sulphate of iron every 4 - 6 weeks throughout the winter months (October - February) before moss becomes a problem will help prevent any moss invasion.