Ingredients of a Healthy Lawn

The five steps to a strong, lush lawn.

By Spike Carlsen

From The Family Handyman

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Ingredients For a Healthy Lawn

The good news is, you don’t have to slave over your lawn to keep it healthy. In fact, to a great extent, it’s not the amount of work you put into your lawn—it’s when and how you do it. The following five “ingredients” are essential for a healthy lawn. We focus on northern or cool-climate grasses like bluegrass and fescue, but most of the information applies to warm climate grasses like zoysia and Bermuda grass, too.

1. Adjust your cutting height to the time of year (and use a sharp blade)
For cool-climate grasses, use a 1-1/2 in. cutting height for the first mowing of the year to remove dead grass and allow more sunlight to reach the crowns of the grass plants. Raise the blade during the heat of summer to 2 or more inches. Then lower the blade back to 1-1/2 in. for the last cutting of the year. For warm-climate grasses, these heights will be about 1/2 in. lower.

When adjusting your blade height, measure from a hard surface to the bottom of the mower deck, then add 1/4 in. (most blades sit 1/4 in. above the bottom of the deck).

Cut your grass using a sharp blade (below left). A dull one tears grass rather than cutting it cleanly. Damaged grass turns yellow, requires more water and nutrients to recover, and is more susceptible to disease. Sharpening and balancing a blade three times a year is usually enough to maintain a good cutting edge—unless you hit lots of rocks.

A Well-Maintained Blade

A sharp, balanced blade cuts grass cleanly and evenly.

A Poorly Maintained Blade

A dull blade shreds grass, leaving it more susceptible to disease and in need of more nutrients to repair the damage. An unbalanced blade compounds the problem (and can damage your lawn mower’s bearings).

2. A few good soakings are better than lots of light sprinklings (but not in the evening)

Deep watering helps develop deep roots that tap into subsurface water supplies (below left). Light sprinklings wet only the grass and surface of the soil; this encourages shallow root growth and increases the need for more frequent watering. As a general rule, lawns require 1 to 2 in. of water per week (from you or Mother Nature), applied at three-or four-day intervals. But this varies drastically depending on the temperature, type of grass and soil conditions. Lawns in sandy soils may need twice as much water, since they drain quickly. Lawns in slow-draining clay soils may need only half as much.

When your lawn loses its bounce or resiliency, or when it wilts, exposing the dull green bottoms of the blades, it needs water. As a general game plan, water until the soil is moist 4 to 5 in. down, then wait to water again until the top 1 or 2 in. of soil dries out. To find out how much water your sprinkler delivers, set out a cake pan, turn on your sprinkler, then time how long it takes for the water to reach a depth of 1 in.

The best time of day to water is early morning. Water pressure is high, less water is lost to evaporation and your lawn has plenty of time to dry out before nightfall. Lawns that remain wet overnight are more susceptible to disease caused by moisture-loving mold and other fungi.

A Properly Watered Lawn

Click image to enlarge.
Lawns that receive an initial soaking 4 to 5 in. deep, and are then watered when the top 1 to 2 in. of soil dries out, develop deep, healthy grass roots. This usually means applying 1 to 2 in. of water per week at three-or four-day intervals. An impact sprinkler delivers water quickly, with less “hang time” for evaporation; a 3/4-in. hose delivers much more water volume than its 1/2-in. cousin.

An Improperly Watered Lawn

Daily waterings promote shallow root growth. Oscillating sprinklers toss water in a high arc, so more evaporates before reaching the soil. Watering late in the evening when your lawn doesn’t have time to dry out allows disease-carrying fungi and mold to grow.

3. Mow only the top one-third of the grass blade (and don’t rake up the clippings)
The top one-third of a blade of grass is thin and “leafy,” decomposes quickly when cut and can contribute up to one-third of the nitrogen your lawn needs. While it’s decomposing, this light layer of clippings also helps slow water evaporation and keeps weeds from germinating.

But the bottom two-thirds of a blade of grass is tough, “stemmy” and slow to decompose. It contributes to thatch, which—when thick enough—prevents sunlight, air, water and nutrients from reaching the soil. Cutting more than the top third also shocks grass roots and exposes stems, which tend to burn in direct sunlight.

This means if 2 in. is your target grass length, cut it when it reaches 3 in. Since grass grows at different rates at different times of the year, “every Saturday” isn’t necessarily the best time to mow. Sometimes you need to mow it more; other times, less. The ideal length for cool-climate grasses is 3 to 4 in.; for warm climate, 1 to 2 in.

Mow when the grass is dry and avoid mowing in the heat of the day when you’re more likely to stress the grass—and yourself.

Click image to enlarge.
Cut off no more than one-third of the grass’s height at a time. The upper leafy grass clippings easily decompose, adding nitrogen to your soil.

Cut off more than one-third its overall height and you’ll not only shock the plant but also leave thick, stemmy clippings that are slow to decompose, and therefore contribute to thatch.

• Revive Tired Grass and a Thinning Lawn
• How to use an aerator and power rake to get an old lawn ready for seeding.
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• Cures for a Patchy Lawn
• Prepare your lawn NOW and enjoy lush grass next spring.
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