Why Soil Preparation Matters More Than Anything
If you remember one thing from this guide, make it this: ground preparation determines whether your lawn succeeds or fails. You can buy the best turf available, lay it perfectly, and water it religiously — but if the soil underneath isn't right, you'll have problems within months.
Poor preparation leads to uneven surfaces, waterlogging, poor rooting, and turf that dies in the first dry spell. Good preparation takes a day of hard work but gives you a lawn that lasts years. This guide covers everything briefly mentioned in our how to lay turf guide in full detail.
Step 1: Clear the Site
Start by removing everything that shouldn't be there.
Old lawn: Strip it off with a turf cutter (hire one for larger areas) or skim it off with a spade. Alternatively, spray with glyphosate-based weedkiller 2–3 weeks before you plan to start, then rotavate the dead material into the soil. The stripping method is faster; the weedkiller method is easier on your back.
Weeds: Perennial weeds like dandelions, docks, and bindweed must be removed completely — roots and all. They'll push straight through new turf if left behind. Annual weeds are less of a concern as they'll die under the new turf.
Debris: Remove stones, rubble, old roots, buried plastic, and anything else that isn't soil. New-build gardens often have builder's waste lurking just below the surface — check by digging a few test holes.
Step 2: Assess Your Soil
Before going further, work out what you're dealing with. Dig down 150mm in several spots across the area.
Is there enough depth? You need at least 100–150mm of workable soil for turf to root properly. If you're hitting subsoil, rock, or rubble before that, you may need to bring in topsoil.
What's the texture? Grab a handful of moist soil and squeeze it. If it forms a sticky ball that holds its shape, you have heavy clay — consider working in sharp sand or grit. If it falls apart immediately, it's very sandy — adding organic matter will help it hold moisture. Something in between is ideal.
Does it drain? Dig a hole about 300mm deep and fill it with water. If it drains within a few hours, you're fine. If it's still sitting there the next day, you have a drainage issue that needs addressing before any turf goes down.
Step 3: Rotavate or Dig Over
Break up the soil to a depth of at least 150mm (about 6 inches). For areas larger than a few square metres, hiring a rotavator makes this dramatically easier. For small areas, a garden fork does the job.
This step serves multiple purposes: it breaks up compaction, incorporates any amendments (sand, organic matter), brings buried weed roots to the surface where you can remove them, and creates the loose, open structure that turf roots need to penetrate.
If your soil is heavy clay, this is the stage to work in sharp horticultural sand or grit — spread a 25–50mm layer over the surface before rotavating so it gets mixed through. Don't use builder's sand, which is too fine and can make clay worse.
Step 4: Remove Stones
After rotavating, rake through the soil and remove any stones larger than about 25–30mm. Small stones below this size are fine — they actually help with drainage. But larger stones create lumps under the turf and prevent a smooth finish.
This is tedious work, but it makes a visible difference to the final result. A landscape rake (the wide, flat-tined type) is much faster than a standard garden rake for this job.
Step 5: Rough Level
Use your rake to pull the soil roughly level, filling in any dips and knocking down any high points. Don't worry about perfection at this stage — you're just getting the general contours right.
If you're working with a large area, it helps to set up string lines at the finished soil level as a reference. Remember that the finished soil surface needs to be about 25mm below any adjacent paths, paving, or edging to allow for the thickness of the turf.
Step 6: Firm the Surface
This is the step most people skip, and it's one of the most important. Loose, fluffy soil settles unevenly after turf is laid, creating dips and bumps that are very difficult to fix afterwards.
Walk across the entire area using short, overlapping steps — the classic "gardener's shuffle." Your weight compresses the soil evenly. For larger areas, a garden roller does the same job with less effort.
You're aiming for soil that's firm but not compacted. You should be able to push a finger in fairly easily, but your footprints shouldn't sink more than about 10mm. If you can't push a finger in at all, you've over-compacted it — lightly fork over the top 25mm and re-firm.
Step 7: Final Rake and Level
Rake the surface again to remove your footprints and create a fine, even tilth. This is your final chance to get the levels right, so take your time. Walk around the area from different angles to spot any unevenness.
A good trick is to drag a long straight edge (a plank or aluminium level) across the surface. Any high or low spots become immediately obvious. Fill and rake until you're satisfied.
The finished surface should look like a well-prepared seedbed — fine, crumbly soil with no lumps, stones, or hollows.
Step 8: Apply Pre-Turf Fertiliser
Scatter a pre-turf fertiliser evenly across the prepared surface at the manufacturer's recommended rate. Lightly rake it into the top 10–15mm of soil.
Pre-turf fertilisers are typically high in phosphorus, which promotes root growth — exactly what new turf needs. Don't substitute a general lawn feed, which is usually high in nitrogen (for leaf growth) and won't give roots the same boost.
Timing Your Preparation
Ideally, prepare the soil 1–3 days before your turf arrives. This gives the soil time to settle slightly but not enough time for weeds to germinate.
If you prepare too far in advance, you'll need to re-weed, re-firm, and re-rake before laying. If you order your turf before preparing, you'll be rushing — and rushing soil preparation always shows in the final result. Use our turf calculator to work out how much turf you need, then order delivery for a few days after you plan to start the groundwork.
For the best time to lay turf, aim for spring or early autumn when the soil is warm and workable. Heavy winter soil is miserable to prepare and doesn't break down into a fine tilth easily.