Sod Calculator

Sod Is Ordered in Slabs and Pallets

A standard US sod slab measures 16 inches by 24 inches, which is 2.67 square feet. A pallet holds roughly 450 to 500 square feet, which works out to about 170 to 185 slabs. Farms vary, and some regions supply rolls instead of slabs, so confirm the slab size and pallet coverage with the supplier before ordering.

Always order extra

Order 5 to 10 percent more than the measured area. Use 5 percent for a simple rectangle with straight edges, and 10 percent for a lawn with curved beds, tree rings, paths or an irregular boundary. Every curve means cutting a slab and discarding the offcut, and offcuts are rarely reusable because sod edges dry out fast.

Running short is the expensive failure. Sod is a living product harvested to order, so a second delivery may be days away, and by then the first batch has knitted in and the new sod will not match in colour or age.

Lawn Size, Slabs and Pallets

These figures use 2.67 square feet per slab, a 10 percent allowance and 450 square feet per pallet.

Measuring the Area

Break the lawn into rectangles, triangles and circles, calculate each and add them. Subtract permanent features such as beds, a shed base or a patio, but do not subtract narrow paths or stepping stones, since the sod around them still gets cut and wasted.

• Rectangle: length x width.
• Triangle: base x height divided by 2.
• Circle: 3.14 x radius x radius.
• Irregular curve: take width measurements at regular intervals along the length, average them, then multiply by the length.

Preparing the Soil

Sod laid on unprepared ground fails, and no amount of watering fixes it. Preparation is the majority of the work and the majority of the result.

1. Clear the site. Kill or strip the existing grass and weeds. Remove debris, stones and roots.
2. Rototill to 4 to 6 inches. This breaks compaction so new roots can move down rather than sit on a hard pan.
3. Amend and grade. Work in compost or topsoil if the soil is poor. Grade the surface to fall away from the house at roughly a quarter inch per foot.
4. Level and roll. Rake the surface smooth, then roll it lightly with a roller about a third full of water. This firms the bed and reveals dips.
5. Set the final level low. Finish the soil about 1 inch below adjacent paths and driveways, because the sod itself adds around an inch of thickness.
6. Water lightly before laying. Moist, not saturated, soil helps roots make contact immediately.

When to Lay Sod

Sod can be laid whenever the ground is workable and not frozen, but establishment is best in mild conditions with reliable moisture. Cool season grasses such as fescue, ryegrass and Kentucky bluegrass establish best in early autumn, with spring a close second. Warm season grasses such as bermuda, zoysia and St Augustine establish best in late spring through early summer, when soil temperatures are rising.

Avoid laying in the peak of summer heat if possible. It can be done, but the watering demand is heavy and the margin for error is small. Lay sod the day it arrives. Stacked on a pallet in warm weather it heats up and starts to yellow within 24 hours.

Laying Technique

Start with a straight edge

Begin along the longest straight boundary, such as a driveway, path or fence line. That gives a true reference to work from, and any accumulating drift ends up at the far side where it is easiest to trim.

Stagger the seams

Lay the slabs in a running bond, like brickwork, so the end joints in each row fall near the middle of the slabs in the row beside it. Continuous aligned seams create channels where water runs through, which dries the edges and leaves visible lines in the finished lawn for a season or more.

Butt the edges tight

Push each slab firmly against its neighbours without stretching or overlapping. Gaps dry out and turn into brown seams. Overlaps create ridges that scalp on the first mow. Fill any small gaps with fine soil.

Laying across a slope

On a slope, lay the rows across the slope, running horizontally along the contour, not up and down it. Horizontal rows resist water running down the seams and washing out the soil beneath. On steeper ground, above roughly 3 to 1, peg each slab with biodegradable sod staples or wooden pegs until it roots.

Cutting to curves

Lay full slabs past the curve, then cut in place from above using a sharp knife, an old handsaw or a spade. Cutting in place gives a cleaner line than trying to pre-measure each piece. Keep cut pieces reasonably large, since narrow strips at the edge dry out and die. Where a strip would end up under about 12 inches wide, remove the adjacent full slab and lay a wider cut piece instead.

Watering the First Two Weeks

Water is the difference between sod that roots and sod that dies. Start within 30 minutes of laying the first section, do not wait until the whole lawn is down.

• Days 1 to 7: keep the sod and the top inch of soil beneath it constantly moist. That usually means watering two or three times a day in warm weather. Lift a corner and check that the soil below is damp, not just the grass above.
• Days 8 to 14: reduce to once a day, watering more deeply each time to draw roots downward.
• Weeks 3 and 4: water every second or third day, deeply.
• After rooting: shift to about 1 inch of water per week, delivered in one or two soakings.

Stay off the new lawn as much as possible for the first two weeks. Test rooting by lifting a corner at around 14 days, and if it resists, the roots have taken. Mow for the first time only once the sod is rooted and the grass is about a third taller than the target height, using a sharp blade and taking no more than a third of the leaf.