What is lawn sand - When & Why You Should Use It

December, 2023
Darren Spalding

Traditionally, the only way to control grass weeds and moss were by using lawn sand. Nowadays with modern weed killers and moss killers designed specifically for use on turfgrass, traditional lawn sand is considered antiquated. So little is known, in fact, that some people aren’t even aware of its existence.

In this article, I’ll explain what it is, when and how to use it as well as some other little tips & tricks!

What Is Lawn Sand?

As the name suggests, lawn sand is a sand-based material used to kill weeds and moss on your lawn. It’s generally sold in bags that are spread evenly over the top of your grass and then raked into place (this allows you to create a more even layer).

There are generally 3 main ingredients within lawn sand:

  1. Iron Sulphate
  2. Ammonium Sulphate
  3. Sand

Iron Sulphate

The thing that kills moss is called ferrous sulphate. The most common way to treat moss with Iron Sulphate is to dissolve it in water and spray it over a lawn.

Iron sulfate has other benefits too, including;

  • Hardens and protects the turf against disease
  • Reduces worm activity, which reduces the production of worm casts
  • Kills broadleaf weeds
  • It will give you a deep, dark green lawn

Ammonium Sulphate

This is a pretty traditional fertiliser, used in a large number of fertilisers it helps brighten lawns.


The sand found in most lawn fertilizers is not beneficial to your lawn at all. Rather, sand provides the fertilizer with more traction which, in turn, means that it will be easier to spread.

What Is Lawn Sand Used For?

The most common use for lawn sand is to control moss. When spread over moss, the granules asphyxiate the moss while leaving grass unharmed. Sometimes, moss can be reintroduced in a scorched lawn. The grass will come back, but moss will stay dead.

Lawn sand also kills broadleaf weeds, allowing the grass to grow more robustly in its place.

Grass likes a near-neutral soil where the pH is somewhere between 5.8 and 7.2, so it can also be added to high alkaline soils with higher acidity in order to reduce the need for lime or other materials that could alter the general chemistry of your garden.

How Does Lawn Sand Work?

Lawn sand is a granular material that quickly dries when exposed to sunlight. As it dries, the Iron Sulphate powder mixes with oxygen and water to produce iron sulphate.

Iron Sulphate or otherwise known as Ferrous Sulphate contains hydroxyl ions ( OH- ) which ultimately reacts with the moss to kill it. Left alone, this reaction of oxidisation within soil would make any lawn or garden appear dead however not immediately obvious as they disappear from view under the moss blanket. As your grass grows back through, you will see no unsightly weed patches in the lawn and no patches of bare patchy areas just an even dense green lawn growing up again - hopefully! With this lovely deep green colour.

So, to summarize, the reaction of iron sulphate combines with water and oxygen in order to oxidize. This may sound like a pretty complicated process but it really isn’t!

How Do You Kill Moss With Lawn Sand?

In order to kill moss with lawn sand, you need to have a pretty even layer of the stuff. You can achieve this by either using your hands or a rake (I recommend a rake).

The most important thing is that you spread it evenly throughout your lawn so that there are no patches leftover. It’s always better to err on the side of caution than using too much or too little.

What Are The Benefits Of Using Lawn Sand?

Lawn sand contains ferrous sulfate which helps increase iron levels in the soil as well as helping control broadleaf weeds and provides many other benefits depending upon different formulations - ample information on the internet regarding these issues!

So what are the benefits? Well: Lowers pH, Lowers mowing height, Helps kill moss and weeds, Controls snail & slug activity.

In addition to this: It adds calcium carbonate which helps fight nematodes in sandy soils as well as being an excellent source of organic matter (to improve the overall health of your lawn).

The Best Application Of Lawn Sand?

It depends on whether you have a large area that needs treating or whether it’s just a small patch that needs fixing up.

If you have a substantially large area with patches in it I suggest spreading out some thick black plastic over the ground - leave around 3-4 inches all the way around then cover with another layer of sand evenly spread over the top. At least 2-3 inches thick on top of the plastic will be enough to ensure that your grass comes back over time.

How Long Does It Take To Kill Moss? Both broadleaf and moss require approximately 3-6 weeks in order for them both to die off however it could take longer depending upon how much you use as well as moisture levels etc.

What Are The Advantages And Disadvantages Of Lawn Sand?

Using lawn sand is an easy and effective way to kill moss if you are looking for a quick solution. It will help to even out your grass over time as its effect is long-lasting, particularly in heavy soils.

The most appealing aspect of using it is that it’s cheap, easy to obtain and seems like a really simple alternative to all the other materials that can often do as much harm as good!

Now there are some disadvantages, however:  It requires a few weeks for full effectiveness meaning that you have to be patient with it; It doesn't cost an arm or leg but it isn't terribly expensive - maybe around £10-£15 for enough sand to cover 2k square feet properly depending on the size of the bag.

When To Apply Lawn Sand?

As with all treatments, it’s best to apply in the spring when your grass is first growing properly. This is because there will be more moisture in the soil and so the effects are likely to last longer and be more effective. The same applies for moss although you may need to re-treat it later on again as they can grow back over time if your pH levels are not correct or too low.

How To Apply Lawn Sand?

As I’ve mentioned a few times already, you can do this using your hands or with a rake. As long as you make sure it’s nice and even, then you are fine. You usually get the best results if you apply a thick layer of sand around 2 to 3 inches thick over the affected area(s).

To Sum Up...

Lawn sand is cheap, effective and extremely easy to use - particularly for those who dislike having to buy chemicals with all their potential side effects! It also helps fertilize your lawn in conjunction with helping kill moss so it's two birds one stone as far as that's concerned.


When should lawn sand be applied?

Lawn sand should be applied every four to six weeks over the late spring and into the summer so that moss and weeds can be gradually taken out while promoting a healthy lawn.

Is lawn sand good for killing moss?

Moss in your lawn can be a tricky weed to get rid of. Lawn sand is a traditional treatment for moss found in lawns (that works, because the dead moss will easily come off using either raking or scarifying the area) and provides other benefits as well.

Does lawn sand feed the lawn?

When you use lawn sand to feed your soil, it will help to prevent compaction and add calcium carbonate. This, in turn, helps to fight nematodes living in sandy soils and is a great source of organic matter for the overall health of your turf.

Can you mix grass with lawn sand?

To make the seed blend more evenly with the existing lawn, mix in a bucket of compost and sand. Then, sprinkle it liberally over the current landscape.

Is lawn sand safe for wildlife?

Lawn sand, applied according to the product’s instructions, does not jeopardize game animals and wildlife.

SpaldingBulb is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.co.uk.
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram