How to Prepare Soil for Sod

Sod almost never fails because of the sod. It fails because it was laid onto ground that roots could not get into, and by the time that shows, the pallets are down and the money is spent.

You need four to six inches of loose, graded topsoil, firmed but not compacted, and the existing ground underneath broken up. Everything below is that, in order.

1. Strip what is there

Kill or remove the existing vegetation. Laying sod over living grass or weeds leaves a mat that holds water at the interface and rots the new roots. If you are spraying, allow the full interval on the label before you cultivate.

Take out rubble, roots and anything that will not break down. A brick two inches below new sod becomes a brown patch every August.

2. Grade in the subsoil, not in the topsoil

Fix your levels before the topsoil goes on. Falls away from the house, no hollows, no high spots where a mower will scalp. Grading afterwards means pushing your expensive soil around and ending up with four inches in one place and one inch in another.

Aim for a fall of about an inch every eight feet away from buildings.

3. Break the interface

This is the step people skip. Loosen the top two to three inches of the existing ground so the new topsoil and the old ground meet as a gradient rather than a line. Roots will not cross a sharp boundary and neither will water — you get a lawn rooted in four inches sitting on a pan.

A rake is enough on soft ground; compacted or clay ground wants a fork or a tiller. Do you need to till topsoil in covers when a tiller is the wrong tool.

4. Spread the topsoil

Four inches over decent ground, six over builder's subsoil. Screened, so there are no stones to sit under a seam.

For 1,000 square feet at four inches you need about 12.3 cubic yards — order around 15 to allow for the 15–20% that settles. The calculator does your area, and how deep topsoil should be explains why more is not better.

5. Firm it, then rake it

Walk the whole area in overlapping steps, or use a roller a third full. You want it firm enough that a boot leaves a shallow print, not a hole — loose soil settles unevenly under sod and you get dips along every seam.

Then rake to a fine, level surface and check with a long board. Sod is thin; it telegraphs every lump underneath it.

6. Water the soil before the sod arrives

Dampen the bed the day before. Laying sod on dry soil wicks moisture out of the roots immediately, and dry soil under wet sod is the classic reason turf lifts in week two.

Damp, not saturated. You should not be laying sod on mud.

Order the soil before the sod

Sod is perishable. On a pallet in summer it starts heating within a day and is unusable in two or three. Have the bed finished before the delivery, not the other way round — and if the sod arrives first, get it into shade and keep it damp.

Work out your soil volume, order it early enough to spread and grade, then book the sod. How much a pallet of sod covers has the coverage arithmetic.

Should it be sod at all?

Seed is a fraction of the cost and, on a large area with time in hand, gives a lawn just as good. Sod buys you instant cover, erosion control on a slope, and a usable lawn now. Grass seed vs sod has the comparison.

Either way the soil preparation is identical, which is the part worth spending on. Find topsoil and sod suppliers near you on Topsoil.com.