Does Glyphosate Kill Moss?

When moss becomes a hindrance on lawns or driveways, and you want to get rid of it. But glyphosate, also commonly known through the band name Roundup, is ineffective at killing moss.
It’s understandable why glyphosate is often considered to carry out the job, as the herbicide was seen as revolutionary when it first entered the market back in the 1970s - and it still boasts a strong brand presence to this very day.

Why is glyphosate not effective at killing moss?

Roundup is a commercial herbicide that contains a mixture of chemicals designed to kill weeds. One of the chemicals it contains is called glyphosate which isn't effective at killing moss. Because plants grow in different ways, the herbicide you decide to use must be appropriate to combat said plant. That means there isn’t a blanket weed killer that will work to kill, say, chickweed as well as moss.

What is the best way to kill moss?

The best defence against moss invading your lawn or driveway is effective maintenance - so a ‘prevention is better than the cure’ approach. However, even committed maintenance can’t guarantee that moss won’t appear (even though it is an effective way of preventing it).


A few things you can do to prevent excess growth moss include:

1. Maintain soil acidity

Healthy lawn grass should have a pH level of between 6 and 7. You can check the acidity of your soil with a soil test kit, which measures the acidity levels. Remember, the lower number, the higher the acidity. And the higher the number, the higher the alkaline level. A well-known trick for reducing the acidity of the soil is to add lime to it.

2. Measure soil moisture

As well as measuring the acidity of your soil, it’s also worth testing the moisture levels. If the soil is too wet, then this will encourage moss to thrive. And if the soil is too dry, the plants or grass will begin to die which paves the way for moss to thrive, since it’s such a resilient species. You can use a rain gauge to monitor the water levels of your soil, and this will tell you whether some drainage or additional water is needed.

3. Fertilise the soil

Soil lacking in sufficient nutrients may cause grass to die and help moss to take over. Fertilising your soil with organic waste helps improve its quality and nutrient content.

4. Reduce shade

Moss thrives in the shade. Cut back trees or remove things that block your grass from getting enough sunlight. This might not always be possible, so an alternative option is to grow a grass species that is tolerant of the shade. Reducing the shade will also help kill moss on tarmac driveways.

5. Scarify your lawn

Compacted soil deprives grass of acquiring the nutrients its needs, yet moss can still flourish. You can combat compacted soil by aerating and scarifying your lawn a few times throughout the year.

But if moss growth still persists, here are some chemical products that can work to get rid of it - for both lawns and driveways.


Does Glyphosate Kill Moss? The simple answer is no


Roundup alternatives to kill moss


Moss killer for lawn

A natural substance that helps to get rid of moss on lawns is iron sulphate. You might also see it called sulphate of iron or ferrous sulphate or sulphate of iron is a natural substance that gets rid of moss. It can also be marketed differently; some companies brand it as a moss killer whereas others promote it as a fertiliser.. Iron sulphate works by rapidly killing the moss on your lawn. Once you’ve applied it to the infestation, the moss will begin to die and thus blacken. Once the moss is dead, you can sweep it away. You might be able to fertilise this moss, which you can learn about in this article on how to fertilise moss.

Moss killer for driveway

One of the UK’s best-selling moss killers for driveways, patios, deckings etc. is Pro-Kleen green mould and algae moss killer. It’s a solution that you mix with water and apply to the surface you want to treat. Since it's mixed with water, a five litre bottle can last you a long time so you can apply it throughout the year to prevent moss getting out of control. An added plus is it’s non-acidic, non caustic, and doesn’t contain any bleach.

So there you have it. Will Glyphosate Kill Moss? No. There are many more efficient solutions out there.