Scheduling the Kindest Cut of All for Lawns

Mowing and watering your lawn are usually done whenever you have the time, rather than on a fixed schedule. But this routine isn’t necessarily best for the grass.

Instead, let the lawn dictate when you mow, using the one-third rule. This rule stipulates that most grasses grow best if you don’t cut more than one-third of their height at one time. Cutting more than one-third leaves too little leaf to gather sunlight and drive the photosynthesis process.

Let’s say you mow the grass to a height of two inches. When it reaches three inches, mow it again. The one-third rule reduces mowing time by nearly a third, and the clippings are small enough that they don’t need to be bagged.

Leaving short clippings on the ground is preferable to bagging them. Clippings don’t add significantly to thatch because they are 90% water, and the 10% of the plant matter adds nutrients to the soil as it breaks down.

Will you need a mulching mower? Not if you follow the one-third rule faithfully. But there will be times when the grass has gotten ahead of you, and a mulching mower would be a big help. A good compromise, however, is a bagging mower that can be used without a bag. If your mower cannot be used safely without a bag, check with the manufacturer about a conversion kit.

Finally, don’t mow your lawn too short. While some warm-weather grasses can be cut as low as 1 1/2 inches, cool-weather grasses should never be cut shorter than two inches in the cooler months and 2 1/2 to three inches during the hottest months. Mowing the grass shorter stresses the root system.

Fewer deep waterings are better than frequent shallow waterings. Light watering encourages shallow root growth and possible heat stress.

There are two exceptions to this rule, however.

First, lightly water newly seeded areas. Second, don’t deeply water cool-season grasses during the hottest weeks of the late summer. Instead, rely on frequent shallow waterings during the early morning to keep your lawn green.

As temperatures heat up in late July and August, cool-season grasses conserve energy by shrinking both their root systems and top growth. With shallow roots, a deep watering wastes water.

Warm-weather grasses, by contrast, need plenty of water during the peak-growth summer months.

You can seed in the spring or fall, but a fall seeding yields better results with cool-season grasses. This is because the young shoots with their shallow roots, cannot bear the heat of the summer.

As such, you can expect a survival rate as low as 50% with a spring seeding. Spring seeding also forces you to avoid using pre-emergent herbicides--one of the most effective forms of weed control--because it may kill the young grass.

To reseed an area, rake the soil to loosen it. Then, apply the seed and rake it lightly. Spread straw on the seeded area to protect from sprinkler erosion, provide shade and maintain soil temperatures on cold days.

After seeding, keep the soil moist for several weeks.