Using lawn sand to control lawn weeds

Lawn Sand is commonly used to control lawn weeds but just what is it and how can we use it? Lawn sand is made up from iron sulphate, ammonium sulphate and fine sand and it can be applied to the lawn by hand or by using a machine. As well as dealing effectively with many types of weeds, lawn sand can be used to control and prevent moss. Although necessary on lawns that are prone to weed and moss infestation due to stress such as shade, drought, waterlogging etc lawn sand should not be thrown at the lawn all the time. A good lawn care programme will help maintain a healthy vigorous lawn that is less susceptible to lawn weeds and moss.

How does lawn sand work?

In order to control weeds and benefit the grass, lawn sand must be selective in which plants it destroys. The difference in shape and structure between grass leaves and weed leaves / moss enables lawn sand to only harm the weeds / moss. When applied to the lawn the lawn sand ‘settles’ on the broad leaves and fibrous mass of moss and scorches them so they are destroyed. Because grass blades are fine with little horizontal surface area the lawn sand slides off and falls between the grass blades and onto the soil / thatch layer. This means that the grass blades are not scorched by the effects of the lawn sand.

When lawn sand reaches the soil it stimulates grass shoot growth and also helps to ‘green’ the lawn. In this sense applying lawn sand acts as a double-edged sword, on the one hand protecting the lawn and on the other hand strengthening the lawns vigour.


The application of lawn sand should be carried in spring (and summer if necessary). Try to choose a dry day to apply the lawn sand and if rain has not occurred after a few days then you can water the lawn.

The weeds must be in mid growth to ensure there is sufficient weed leaf area for the lawn sand mixture to settle upon. For the same reason, do not cut the lawn for at least 3 days before applying the lawn sand to ensure the weeds have sufficient leaf area.

Lawn sand is more environmentally friendly than most other chemical lawn weed killers but you should still take good care when applying it to your lawn. Make sure to follow the manufacturers instructions with regards to the amount to apply per square metre or square foot. Rather than applying the sand directly out of its bag try and find a suitable sized container and work out how much area that sized container will cover. You can then be consistent in your application by refilling the container and starting a new calculated area of lawn.

After application do not mow the lawn for at least 3-4 days so that the effects of the treatment can start to work. Avoid putting the clippings from the first mower cut on the compost heap as they can contain higher than normal levels of chemicals.

Using lawn sand to control lawn weeds

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