Top dressing the lawn

What is top dressing and why top dress the lawn

Another important task in any lawn care program is that of top dressing your lawn, especially if you desire or already have a luxury lawn.

Top dressing is the process of applying a layer of suitable material such as sand, soil and peat to the surface of the lawn. Top dressing the lawn on a regular basis has many benefits which include:

• Smoothing out any minor undulations or hollows on the surface of the lawn.

• Encouraging finer, more desirable grasses such as bents and fescues. Bents and fescues being the preferred grasses for fine turf luxury lawns.

• Top dressing the lawn encourages the grass to produce side shoots, resulting in improved sward density and a healthier lawn.

• Helps to control and dilute the thatch layer in the lawn.

• Improves the drought resistance of the lawn.

• Reduces water logging and helps with the drainage of the lawn.
  

Materials used for lawn top dressing

There are 3 main materials primarily used for lawn top dressing, these being sand, loam and peat. Each of these materials have there own benefits to the lawn.

We will have a look at these top dressing materials in more detail:

• Sand - Choose a lime free sand of medium particle size, avoiding course and particularly very fine particles. It is important that the sand is lime free (a sand that contains a high lime content can cause problems with worms, disease and weeds). Sand helps with the drainage on a lawn.

• Loam - Use a quality loam that is friable and does not contain a high percentage of clay. This can be purchased from most good garden centers. Loam contains an equal amount of sand, silt and clay, a sandy loam is arguably the ideal growing medium for a luxury lawn.

• Peat - a good quality sphagnum or sedge peat would be ideal for the top dressing mixture. Peat will help with moisture retention on lighter, sandy free draining soils.
  

How much of each material you apply to your lawn will depend on the root zone or soil that your lawn is constructed upon. E.G. A lawn on a light sandy soil will probably suffer from drought problems during a dry summer.

Therefore in this case you would require a top dressing containing a high proration of loam and peat and very little sand to help with moisture retention. A lawn that has a high clay content would require a higher percentage sand to help with the drainage.

For a quick guide on what mixture to use on your lawn the table below can be used as a reference. Note This is only a guide and the mixtures are not set in stone.

• Sandy soil - 2 parts peat, 4 parts loam, 1 part sand

• Heavy soil - 1 part peat, 2 parts loam, 4 parts sand

• Loamy soil - 1 part peat, 4 parts loam, 2 parts sand
  

When to top dress a lawn

The most common time of the year to top dress a lawn is late summer / early autumn. However it should be noted lawns can in fact be top dressed anytime during the growing season from April to October.

Lawn top dressing should be included in the autumn renovation program and is sometimes incorporated in the spring renovation program too. Top dressing is often applied after scarification, aeration and overseeding operations have been undertaken.

How much top dressing too apply to a lawn

When applying a top dressing to a lawn there is no set application rate. Top dressing rates can vary anywhere between 1.5kg to 4kg per square meter. The heavier rates would be used during the spring and autumn programs after scarification and or aeration has been completed.

Lighter rates would be used during the growing season when there has been less disturbance to the lawn and recovery is not as critical.

How to top dress the lawn

If part of the autumn of spring programs the top dressing will be applied after the lawn has been scarified and or aeration and or overseeding has been completed.

Choose and dry day and ensure both the top dressing and surface of the lawn are dry. Mowing the lawn prior to application will help make the top dressing operation easier, especially when brushing in the material.

Tip equal size heaps of top dressing on the lawn ready for spreading. The top dressing can now be spread as evenly as possible over the lawn, using a shovel. If your lawn covers a large area, powered spreaders are available for hire for this task.

The top dressing should be left to dry out completely, before rubbing it into the sward. You can use a purpose built tool like a true lute, brush or drag mat for this task, or alternatively the back of a rake or flat board on a wooden shaft will suffice.

Ideally leave the lawn a few days before mowing and if possible raise the height of cut on the mower to avoid picking up any of the top dressing material.