What is the best soil for turf?

04th Feb 2019

Whether you are installing a new lawn, or you need to topdress an existing lawn, what is the best soil for turf?

Turf Underlay

Turf underlay is the foundation or bed for your turf to grow on. You only get one chance to get this right as once your turf is down it’s too late. Turf underlay generally is a mix of the following:

  • Washed river sand, medium to course particles – some % of clay is present which helps to compact and form a base.
  • Some heavier soil is generally added which helps to hold moisture and mixed with the sand creates a free-flowing profile for water movement.
  • A composted material is then added – again generally this can be green waste, chicken or animal manure and some natural nutrients to help balance your pH levels.

Once this is all mixed together it will form the turf underlay you require – a firm base that allows water movement downwards and allows for water retention, so the turf's root system can develop and establish. The aim is to promote a healthy root system that will protect the turf from weather conditions such as droughts and winter frost.

When you put in your turf underlay, it is recommended to apply to a depth of 100mm as a minimum, sometimes more is necessary. Prior to spreading your turf underlay, spray out all existing weeds and grasses. Once you spread your turf underlay ensure it is levelled, rolled and watered prior to installing your new turf.

Top dressing

For a top-dressing material, we always like to use Plasterers Sand. It doesn’t compact quite as hard as brickies sand. It is generally easier to screed and level due to the lower clay and silt content and reduces the likelihood of the surface crusting and become hydrophobic.

Topdressing your lawn allows you the opportunity to fill in any unevenness and should be applied at no more than 5-10mm in thickness at a time. The sand should be rubbed in evenly using a lawn level bar, working the sand down into the turf thatch layer. When preparing your turf for topdressing, if possible, apply a general-purpose fertiliser, wetting agent and water in well a couple of days prior. This will give your turf the growth required to surge through the topdressing sand.

Well and truly putting the great Australian lawn back on its pedestal as the centrepiece of all great Aussie backyards!