Nowadays, lawn sand has fallen out of favour – so much so that many people haven’t even heard of it. Yet it was once a popular lawn treatment, and it still has value today – and if you want to know more, here we talk about what is lawn sand & 5 reasons why you should use it.
If you want an introduction to some of the stuff we’re going to be talking about, check out this video before reading on.
What is lawn sand?
Lawn sand is something of a rarity among gardeners nowadays, and using it is considered old-fashioned – but it was once much more common.
This is because it has now been superseded by more focused products, but it is still available, and there is still a place for it in modern gardening.
Lawn sand is a treatment that is made up of three ingredients, ferrous sulphate (sulphate of iron), ammonium sulphate (sulphate of ammonia) and sand.
The ratio of these three components is usually around 1:3:10, although this can vary, depending on the producer.
The main active ingredient is ferrous sulphate, which can kill mosses as well as broadleaved weeds. At the same time, it can also discourage earthworms and even help give your grass a greener colour without stimulating excessive growth.
Ammonium sulphate is a common nitrogen-based fertiliser that grass requires to grow, and its presence helps grass recover from the harmful effects of the ferrous sulphate, allowing it to regrow faster. It can also help raise the pH level of your grass.
The sand has no effect on the grass and is added merely as a medium to carry and deliver the other two ingredients.
What is Lawn Sand used for?
The traditional and best known use for lawn sand is as a way to control moss. When spread over moss, it scorches the moss, killing it off while leaving the grass unharmed.
Sometimes, grass can become scorched at the same time, especially if the lawn sand is not applied carefully, but even when this happens, the roots will be left intact and the grass will rebound while the moss will stay dead.
As we mentioned, lawn sand also scorches the leaves of broadleaved weeds, killing them off and allowing the grass to grow strongly in their place.
The nitrogen content also fertilises the ground, and since most grasses prefer an acidity in the range of around pH5.8-7.2, it can also be used to lower the acidity in the soil where the acidity is too high.
How does Lawn Sand work?
The theory behind lawn sand is that since it’s delivered in the form of a fine powder, it sticks to the leaves of broadleaved weeds and covers any moss in the lawn while not attaching itself to the narrow leaves of the grass itself.
This is why the undesirable weeds and moss are destroyed by it while the grass is left unharmed – or at worst, only temporarily damaged.
What are the advantages and disadvantages of Lawn Sand?
There are several advantages to using lawn sand, some of which we have already mentioned. As we just saw, it selectively kills moss and weeds while allowing your grass to continue to grow, and it also increases your lawn’s overall resistance to disease.
As noted, it discourages earthworm activity while also improving the colour of your lawn. At the same time, the ammonium sulphate fertilises your grass, encouraging strong growth.
So in short, the main advantage is that applying lawn sand to your grass brings a range of benefits rather than focusing on one specific area.
However, that’s not all. Lawn sand also tends to be cheaper than many more modern herbicides or fertilisers, and it’s also extremely easy to spread.
Finally, lawn sand can be used frequently, anything up to every 4-6 weeks, unlike more potent herbicides, so despite being ‘old-fashioned’, it’s still got a lot going for it.
On the downside, however, if you want something for one specific job, other products may be more effective. For example, while lawn sand can deal with minor growths of moss, for more serious cases, dedicated moss killers are a better way to deal with the problem.
Also, the fact that it can scorch grass, leaving unsightly patches in your lawn, can put some people off – even if the grass is likely to grow back quickly after the treatment.
When to apply lawn sand
One of the keys to getting the best results from lawn sand is knowing when to apply it, and the secret is not to get over-eager and spread it too early in the year.
More specifically, if you apply lawn sand while the weather is still too cold, the ferrous sulphate will kill any moss, but the ammonium sulphate won’t help the grass grow back.
Instead, wait at least until mid-March before beginning your treatment. However, this is only a rough guideline since there is considerable variation between the north and the south of the UK as well as from one year to the next.
A better way to judge is to wait for the first signs of growth in your lawn that indicate an increase in temperature before applying lawn sand.
How to apply lawn sand
Lawn sand can be applied either by hand or using a spreader, and it is important to use the right amount. If you apply too much, it will scorch your grass as well as any moss or weeds.
The correct dose depends on the product you buy, but it is usually around 100-150g per square metre. For this reason, you should read the instructions carefully before you begin.
Spreading it by hand is a less accurate method, so you might find it helpful to divide your lawn up into squares using string and pegs. Once you’ve done this, measure out the correct amount for one square metre and spread it evenly within one of your squares.
This will show you what the correct amount should look like on the ground, and you can then use this as a visual guide to copy for the rest of your lawn.
On the other hand, if you are using a spreader, you just set it up to deliver the required amount and then start pushing it over your lawn. You just need to be careful not to overlap when turning or you can still deliver too much.
Pro tips for success
Whichever method you use, it’s best to mow the lawn before you start – and don’t mow the lawn for at least three days after you’ve finished.
Lawn sand needs water to help it into the soil, allowing it to start working; if it doesn’t rain within 48 hours after applying it, you should water your lawn to prevent it from scorching your grass.
After rain or the first watering, your lawn will be safe to walk on or for children or pets to play on – although you shouldn’t let grazing animals on it for at least four weeks.
Two weeks after the application, you should then scarify your lawn with a rake or with a scarifying machine to clear away any dead moss or weeds.
Avoid using lawn sand on newly seeded lawn for the first six months – but you can reseed or overseed your lawn four weeks after a treatment.
Reasons you should use lawn sand on your lawn
To summarise, here are some of the main reasons why you should incorporate spreading lawn sand into your regular lawn care schedule.
1. It’s a holistic treatment
Although traditionally used to deal primarily with moss, lawn sand offers you a more holistic way to care for your lawn since it deals with several problems and brings a variety of other advantages in a single treament.
2. It’s less expensive
Although not as effective as some of the more modern products designed for specific weeds or mosses, lawn sand is generally a cheaper option, meaning you can save yourself a bit of money by choosing it to deal with less serious issues.
3. It’s easy to spread
Lawn sand doesn’t require any special mixing or preparation. You just need to spread it over your grass as it is, either by hand or using a spreader. The only thing you need to be careful about is the dosage since using too much can harm your lawn.
4. It’s forgiving
Even if you do use too much and end up damaging your grass, your lawn will be able to repair itself. It may scorch the leaves, but the roots will remain intact, and your grass will quickly grow back again.
5. You can repeat treatments often
Unlike with some herbicides or fertilisers, you can repeat your grass treatments as often as every 4-6 weeks if required.
An old-fashioned treatment that still has its uses today
As you can see, despite having fallen out of favour, lawn sand still has a lot going for it. This means, if you know what it is and what it’s useful for, it can still play a vital role in your regular lawn care cycle, even today.