The Causes of Moss in Lawns

If you want a decent lawn then you need to help the grass and NOT help the moss – it’s LAWN CARE vs LAWN MOSS!

If the conditions in your lawn aren’t perfect, and they rarely are you may have a moss problem. In other words the natural balance in your lawn is towards moss and away from grass. Without any intervention the problem may get worse and, in some cases so bad that you have all moss and no grass!

There are three main causes of moss in lawns:

Lawn care practices

• Scalping the lawn by mowing too close
• Scalping high points because of a bumpy lawn
• Infrequent grass cutting
• Not following the ‘one third rule’ for mowing
• Not aerating heavily used or compacted areas
• Poor or inadequate use of fertiliser products
• Not repairing damage from heavy use
• Not removing leaves in autumn
• Not removing excess thatch

‘Local’ environmental factors

• Shady lawns
• Clay soils or poor drainage
• Poor air circulation and heavy dew
• Dry areas such as lawn edges
• North facing lawns
• Acidic soil

Climatic factors

Ideal conditions for moss growth:

• Wet climate (the West Country is usually wetter than the east)
• Excessive rainfall – 2006, 2007, 2008, winter 2014 and 2019
• Cloudy cool summers 2007, 2008, 2009, 2012, 2020

Poor conditions for grass growth:

• Hot summers 2003, 2004, 2006, 2019, 2021
• Dry summers 2010, 2019, 2021
• Cold dry spring 2010, 2013, 2015

As can be seen from the above, moss can grow in your lawn in quite a wide variety of conditions. The more suitable the conditions however, does not always mean more moss because lawn care practices can have the greater influence. A lawn scalped once a month with dull blades may well have moss even if it’s in a sunny dry location! The reverse may be true for a well maintained but slightly shady lawn.

Therefore, a lawn in an ideal environment with good lawn care practices will have little or no moss. The fact of the matter is that in this situation the grass thrives and the moss doesn’t get a look in. It is only when conditions turn against the grass such as permanent shade or mowing abuse that the grass is weakened and allows moss to take a hold.

It is no different for you. Have a few sleepless nights, over do the wine, boss on your back, over worked, stressed out and you soon feel out of sorts. And when you’re run down your health suffers and quite possibly you go and catch a cold! Not a lot different from your lawn catching moss!

Therefore, looking after your lawn, just like your health, is the most important thing in the war against moss.