How to control moss and algae in lawns

Author: Stefan Palm   Date Posted: 17 June 2020 

If you notice moss and algae growing in your lawn, I'd advise you to do what you can to get rid of it. While it can look OK, it has the potential to take over your lawn.

Winter is the time when moss and algae is most prevalent in lawns. This is because of the cool temperatures, the extra rain around and the lack of warmth to dry up surface moisture. Add shade into the picture and all of a sudden you have an irresistible environment for moss and algae to thrive in.

Moss and algae come in a variety of forms and love to grow in lawns. It can look innocent enough but can successfully out-compete a lawn in a short space of time. Left untreated, moss and algae can completely take over, especially where the lawn is weak or patchy. It does this by spreading underneath the lawn, occupying almost all of the soil space - eventually the lawn simply gets crowded out. The good news is that it is relatively easy to get rid of however you will need to consider how to stop it from growing back.

To remove it, try the following methods:

  • Apply Iron Sulphate. While toxic to moss and algae, your lawn will love it - you might even find that it greens it up during winter. Apply at the rate of 40g/m2 but avoid exposure to hard surfaces like pathways - it will leave nasty rust stains. The moss and algae should curl up its toes within 7 days. 
  • Physically remove it with a rake or by hand. 
  • By far the safest and easiest way to control moss and algae in your lawn is with a product called Wet and Forget. It’s a liquid that you mix up and spray on. Wet and forget is safe to use on lawns, pathways, furniture, timber, fibreglass and the list goes on. All you need to do is spray it on and forget about it. It’s easy to use, it's safe and it works.

Attempts to eradicate moss and algae from a lawn are rarely effective unless you understand why it grew there in the first place.  Encroachment of moss into lawns is usually the result of conditions that are not conducive to good growth of lawn. Moss and algae is most commonly associated with shallow, rocky soils, poor soil fertility, low soil pH (acid soils), heavy shade and excessive moisture. If any of these factors are limiting turf growth, moss and algae can invade the lawn and establish a permanent residence. I would recommend the following preventative measures to reduce the likely-hood of moss and algae:

  • As much as possible, remove the conditions that moss and algae love to grow in. For example, solve any drainage issues so that moisture isn't lingering on the surface and try to introduce more sunlight. Have the lawn cored and consider topdressing with gypsum. 
  • Ensure that your lawn is as healthy as possible coming into winter. The patchier your lawn is, the more opportunity moss and algae will have to grow.  
  • Fertilise your lawn in Autumn since moss and algae prefer low nutrient levels
  • Have your soil pH checked. If its too acidic, correct it using garden lime. 
  • You also need to ensure that once you have removed it that you replace it with a healthy lawn. 

If you have moss problem that you can't seem to get on top of, give us a call on 8298 0555 or send an email to

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