Factors that Affect the Best Time to Mow New Grass
Here are the most important factors affecting new grass growth and the best time to pull out the mower.
Sod vs. Seed
Sod already has a significant head start in growth, so you can plan to mow it for the first time about 3 weeks after installation. Remember to check that the sod has established firmly enough to mow. You can quickly determine whether you need the mower by tugging on a chunk of sod: if it lifts or gives easily, wait another week to mow.
On the other hand, if you planted grass from seeds, then it can take up to two months for the grass to become properly set.
Fast vs. Slow Grass Growth
Some types of grasses grow faster than others. Ryegrass and fine fescue, for example, are known to be particularly fast growers and you can expect to mow them earlier on. Species like Kentucky bluegrass grow quickly but have a long germination term, so you’ll need to stay patient. Regular watering can speed up the growth, but be careful not to overwater.
Local Climate
Warm, humid growing seasons like mid-spring tend to encourage turf growth and may shorten the time until you need to mow. But cold or dry weather can slow down new grass development.
You should also consider the level of grass dampness before mowing for the first time. Damp grass makes poorly cut grass. Lawnmower blades, even when sharpened, can struggle to properly cut wet grass, leading to missed patches and the dreaded lines of still-standing blades. Wait until grass is fully dry and avoid mowing after rain.
Ideal Grass Height
Not all grass is made to be cut at the same height, which has a significant impact on how long you should wait before mowing. St. Augustine grass does best at a medium height of 2½ to 3 inches. Tall fescue grows best at 2 to 4 inches, so it may take a bit longer to grow. Bermuda grass is infamously low and should be cut at 1 to 2 inches, so it may be ready much more quickly.
Grass Sensitivity
If your type of grass is especially vulnerable to hot weather or sunlight, it’s a good idea to mow after the day has cooled down, rather than risk that sensitive new grass gets damaged. Consider mowing cool-season grasses in the evening to avoid full sun exposure while cutting.