How to Seed a Lawn

If you’ve spent the summer lamenting your tattered yard or wishing that your patch of dirt were a blanket of soft blades, you can stop.

It won’t get any better, at least not this year. But next spring could be a whole other story if you seed this fall – the perfect time to start a new lawn. In cold-weather climates, fall’s cooler temperatures prevent the seeds from drying out, but there’s still enough sun and rain to help them germinate before going into hibernation for the winter, without the competition of crabgrass and other weeds that die off this time of year. And the best part is that the whole process is a cinch.

“Seeding is the easiest thing for a homeowner to do,” says This Old House landscape contractor Roger Cook. “It just takes a little soil preparation, the right mix of seed, and lots of watering.”

Step 1

Seeding Overview

As with most landscaping projects, preparation is the most critical part of seeding a lawn. The condition of the soil has to be ideal to coax the tiny grass seeds into germinating. That means using well-turned earth with proper drainage and the right chemistry.

To get these conditions, you first need to remove any vestiges of the old lawn. Renting a sod cutter for about $75 to $100 a day allows you to slice off old grass and weeds at the roots. Then it’s time to turn the soil with a rotary tiller, adding sand and compost in successive layers to achieve an ideal mix.

But even with these additions, no soil is ready for seeds if it doesn’t have the right pH. The pH scale measures acidity and alkalinity, denoted by numbers from 0 to 14, with 7.0 being neutral. Grass grows best in soil that has a pH between 6.0 and 7.5. If your soil is too acidic (below 6.0)—a common problem in cooler wet climates like the Northwest and Northeast—you can add lime to bring it up. If it’s mildly alkaline (7.5 to 8.0), a little peat moss, which is naturally acidic, should correct it. Soil that is very alkaline (more than 8.0), which is more likely to exist in dry, hot climates, needs sulfur.

All soil could use a little fertilizer boost to nourish the seeds. Then once the soil is ready, the actual planting is cake. Just throw out the right amount of seeds, gently rake them into the turned earth, and make sure they get enough water to keep on growing.

Step 2

Test the Soil pH

Put measured amounts of soil and water into the test kit’s plastic test chamber and shake well. Wait a minute or two for the soil to settle and the color to develop.

Hold up the vial and compare the color of the soil solution to the color-coded chart printed beside the test chamber. It should read between 6.0 and 7.5.

If the reading shows a pH lower than 6.0, your soil is too acidic and you’ll need to add lime in Step 5. If it’s above 7.5, the soil is too alkaline. For moderately alkaline soil add peat moss in Step 5; for very alkaline soil, use sulfur.

Step 3

Remove Rocks and Roots

Using a pointed shovel, dig up all rocks and roots that are visible (shown here) including any stones that won’t fit through the tines of a garden rake. Fill holes and depressions with topsoil dug up from a high spot.

Use a rotary tiller to turn the soil until there are no big clumps or patches of packed earth. Use a fiberglass-handled shovel, which is less likely than wood to split or snap, to dig out rocks.

Step 4

Add Sand and Compost

Cover the planting area with 1 inch of sand. Use a wheelbarrow to transport it to the site. Distribute it as evenly as possible with a shovel. Use a rotary tiller to incorporate the sand into the topsoil.

Now cover the area with an inch of compost, distributing it in the same manner as the sand. Again, use a rotary tiller to incorporate the compost into the soil and sand.

Step 5

Amend the Soil

Adding lime, peat moss, or sulfur balances the soil’s pH level and boosts nutrients.

Distribute peat moss with a shovel from a wheelbarrow. For lime or sulfur, apply it with a walk-behind broadcast spreader, set to the appropriate distribution rate. Coat the entire area, making sure you don’t miss any spots.

Next, use the broadcast spreader to apply starter fertilizer to the entire area. Make sure the spreader is adjusted to distribute at the rate outlined on the fertilizer packaging.

Step 6

Rake the Soil

Use a metal garden rake to carefully work the lime (or sulfur) and fertilizer into the top inch of soil.

Finish-grade the soil by raking it level.

Tip: Don’t try to spread the fertilizer, lime, or sulfur by hand—or mixed together in the spreader—as they must be applied at different, specific rates.

Step 7

Spread the Grass Seed

Disperse grass seed evenly over the soil, cranking the handle of a handheld broadcast spreader. For larger lawns, use a walk-behind spreader.

Be sure to apply an even amount of seed to the entire area

Step 8

Rake in the Grass Seed

Take a plastic leaf rake, turn it upside down, and use the back of the tines to gently work the seeds into the soil.

Make short, light strokes. Avoid long sweeping motions, which can redistribute the seeds and cause the grass to grow in uneven patches.

Tip: Don’t compact the seeds with a weighted roller because it will create depressions that collect water.

Step 9

Water Regularly

Immediately after sowing the seeds, lightly water the area with a fan-or oscillating-type sprinkler. Set up one or more sprinklers, or move the sprinkler to ensure that the entire area gets dampened.

For the first 8 to 10 days, water two or three times daily, but only for 5 to 10 minutes. Avoid overwatering, which may wash away the seeds. Once the grass sprouts, water once a day for 15 to 30 minutes. It’s typically best to water in the morning, when there’s less evaporation. Avoid watering in the evening; it can lead to fungal diseases.

Tip: If you’re having an automatic sprinkler system installed, be sure it’s equipped with a rain sensor that prevents it from operating during rainstorms.

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