Mowing heights are important for a multitude of reasons including but not limited to, weed pressure, disease pressure, healthy plant growth, desirable plant color, and increased turfgrass density.
As we get into the growing season, we want to be sure to be mowing at the correct heights. Mowing heights are important for a multitude of reasons including but not limited to, weed pressure, disease pressure, healthy plant growth, desirable plant color, and increased turfgrass density.
The last point, increased turfgrass density, is where we’ll spend our time today. Turfgrass density is defined simply as how dense or “full” your stand of grass is. If you look across your turf stand and see no bare patches, we would say you have a dense stand. If the opposite is true, then you have a thin stand. How does mowing height affect your turfgrass density? Depending on the turf type (cool or warm season) we will recommend either the tallest setting or the lowest setting, which will increase the turfgrass density.
For cool-season turfgrasses like Tall Fescue, Kentucky Bluegrass, or Ryegrass, there is a mowing height range that helps optimize density. That range is from 3” - up to the maximum setting your mower will allow. Why is this important? Most of the referenced cool season grasses are grown from seed and are called “bunch type” grasses. Meaning when these seeded grasses grow and mature and are mowed at the highest setting recommended, they grow alongside each other and form a uniform vertical turfgrass stand. Uniform vertical growth is key to a healthy cool season turfgrass stand.
When these grasses are mowed below the recommended heights, they expose more of the crown (the main growing point of the plant) and more of the soil that is supposed to be shaded. When this occurs, you not only stress the plant, which causes poor plant health and growth but also encourage weed seed growth in the exposed bare soil. Like all plants, weed seeds need sunlight to grow and prolonged exposure to this bare soil increases their likelihood of growth and development to a fully mature weed plant.
The inverse of this is when you are maintaining a warm season turfgrass, like Bermuda and Zoysiagrasses. These turfgrass types are called creeping/mat-forming turf types. They grow from vegetative structures called Rhizomes (below-ground roots) and Stolons (above-ground roots). Stolons are also called runners and you experience these running into your mulch beds and are next to impossible to keep out! To drive a dense warm warm-season turfgrass stand, it is imperative to mow on the lowest setting your mower will allow, without scalping! This mowing height encourages the turfgrass plant to grow laterally, not vertically. Lateral growth is key to a dense warm-season turfgrass stand.
At Canopy Lawn Care, our HealthyLawn Program strives for the healthiest, weed-free, and longest-lasting green grass on the block. Our treatments can only do so much if mowing heights are incorrect. If there’s only one cultural practice recommendation you follow, mowing height is number one!
