How to control moss in lawns

With all the rain around of late, combined with the predominantly cloudy days, you may have found moss growing in your lawn. When it comes to the health of your lawn, moss is not a good companion and must be controlled asap!

During Winter, it’s not uncommon to see moss growing through your lawn, and while it can look innocent enough, it can successfully out-compete a lawn in a short space of time. Left untreated, it 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'll need to consider how to stop it from growing back.

Why and how do moss grow?

Encroachment of moss into lawns is usually the result of a combination of wet, shady and cold conditions, which are fairly typical during Winter. In addition to this, they are most commonly associated with shallow, rocky soils, poor soil fertility, low soil pH (acid soils), heavy shade and poor drainage. If any of these factors limit turf growth, moss can invade the lawn and establish a permanent residence.

Moss spreads through several mechanisms:

• Rhizoids: Mosses have structures called rhizoids that anchor them to the soil. These rhizoids can help the moss spread laterally across the lawn by attaching to new areas of soil as the moss colony expands.
• Spores: Mosses reproduce by releasing spores, which are tiny and lightweight. These spores can be carried by the wind, water, or animals to new locations within the lawn. Once they land in a suitable environment, they germinate and form new moss plants.
• Fragmentation: Mosses can also spread through fragmentation. Small pieces of moss can break off and be transported to new areas. If these fragments land in favourable conditions, they can grow into new moss colonies. This can happen through foot traffic, lawn mowing, or animals moving through the lawn.

Why is moss more of a problem during Winter?

Moss can become more prevalent in lawns during winter for several reasons:

• Less competition from the lawn: Most types of lawns go dormant or grow much more slowly during the Winter. This reduced competition allows moss to spread more easily as it doesn't have to compete with actively growing grass.
• Higher moisture levels: Moss thrives in damp environments, providing ideal conditions for it to spread
• Higher shade levels: With the sun being lower in the sky, lawns can be exposed to shade for longer, which again favours moss growth.  

How can it be managed?

Small patches of moss in your lawn during the Winter are no big deal. It's when it starts to dominate that it becomes a problem.   I would recommend the following preventative measures to reduce its likelihood:

• As much as possible, remove the conditions that moss loves to grow in. For example, solve any drainage issues so that moisture isn't lingering on the surface and introduce more sunlight. Have the lawn cored and consider topdressing with gypsum. 
• Where possible, reduce the amount of shade present. This may include pruning tree canopies. 
• For areas that receive heavy shade, introduce shade-tolerant varieties of lawn to maintain a good cover. 
• Ensure that your lawn is as healthy as possible coming into winter. The patchier your lawn is, the more opportunity moss will have to grow.  
• Fertilise your lawn in Autumn since moss and algae prefer low nutrient levels.
• Have your soil pH checked. If it's too acidic, correct it using garden lime. 

What can you do to treat it?

Where you have significant amounts of moss, you'll need to remove it before it takes over your lawn. Try the following methods:

• The safest and easiest way to control moss 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, lawns, 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.
• A non-chemical alternative is to apply a combination of Iron Sulphate and gypsum. While toxic to moss, your lawn will love it - you might even find that it greens it up during winter. Iron sulphate is best applied at the rate of 30g mixed with 70g of gypsum per square metre of area. Adding gypsum to the iron gives it some bulk, making it easier and safer to spread. Apply the mix evenly to a dry lawn and then water in after 12 hours and avoid overapplying. 1kg of this mix must cover at least 10 square metres; otherwise, you risk over-applying, which can damage your lawn. Avoid exposure to hard surfaces like pathways - it will leave nasty rust stains. The moss and algae should curl up their toes within seven days, at which time they can be raked off.  
• Physically remove it with a rake or by hand. 

If you have a moss problem that you can't seem to get on top of, give us a call on 8298 0555 or send an email to stefan@paulmunnsinstantlawn.com.au. We'll help you get on top of it