When To Cut Grass after Overseeding (And why it is necessary to wait)

After noticing that your once plush-looking lawn was thin and patchy, you opted to treat it by overseeding. Now it has been a little over a week since distributing the new seed and it is clear that your lawn is well on its way to its former glory.

Back then you mowed the lawn once a week and you are wondering if this trend should now continue with the new grass.

When should you cut grass after overseeding?

The general time frame recommended before mowing an overseeded lawn is anywhere between 2 and 4 weeks. However, this cannot be taken as a hard and fast rule. It all comes down to ideal grass lengths which different types of grass must achieve in order to withstand the stress of mowing. Some grasses only need to achieve minimal height while others need to be fairly tall to be strong enough for first cutting.

When is the Best Time to Cut Grass after Overseeding?

Many gardeners are keen to get their mowers on new grass soon after overseeding. It is common knowledge than seeds need time to rest and form well established roots, so no gardener will be attempting to mow in the first week after overseeding.

The key questions is exactly how long is necessary?

There is no blanket answer in terms of duration. The answer lies in the height of the grass. It is best to cut the grass only after it has grown to sufficient height to allow it withstand the stress of cutting. How long it takes to grow to this height, and the ideal cutting height depends on the type of grass.

Type of Grass, Ideal Heights and Seasons

If overseeding was done with warm-season grass seeds such as Zoysia grass, Bermuda grass or Buffalo grass, you will not need to wait long during warmer times of the year. These thrive and therefore grow fastest in the summer.

Cool-season grasses like Fescue, Kentucky bluegrass or Perennial Ryegrass thrive in fall and spring seasons.  If overseeding was done with these types and during these ideal times of the year, it achieves the required height much faster.

2 -4 weeks

You should only cut the grass once recommended height ranges are achieved. The rule of thumb is that grass should be given anywhere between 2 and 4 weeks after overseeding before you can even consider doing any cutting. This is the period when root establishment occurs and it should not be disturbed.

Recommended Heights

Below is a table indicting exact heights at which different types of grass should be mowed after overseeding.

	Grass type	Deal cutting height after overseeding ( in inches)
Warm-season grasses	–          Bermuda –          Bahia –          Centipede –          Buffalo –          St. Augustine –          Kikuyu –          Zoysia	0.5 – 2.5 2.5 – 4 1 – 2.5 1.5 – 4 1 – 3 1 – 1.5 0.5 – 3
Cool-season grasses	–          Kentucky Bluegrass –          Fine and Tall Fescue –          Perennial ryegrass	0.75 – 3.5 1.5 – 4 0.75 – 2.5

Information in this table shows that warm-season grasses like Bermuda grass and Zoysia grass can be cut at shortest heights of 0.5 to 2.5 inches and 0.5 to 3 inches respectively.

Centipede grass and Kikuyu grass are best cut at mid-range heights of 1 to 2.5 inches and 1 to 1.5 inches respectively. Bahia grass needs to grow the tallest of warm-season grasses, requiring to be at least 2.5 inches tall.

Among Cool-season grasses, Kentucky bluegrass and Perennial ryegrass require to be 0.75 to 3.5 inches and 0.75 to 2.5 inches respectively. Fine and tall Fescue must be at least 1.5 inches tall.

It may be difficult to measure the length of grass blades in your lawn. If you opt to make visual estimations, the rule of thumb will be useful. It dictates that you should never cut off more than a third of the total blade length in a single cutting.

Lawn Mower Settings

Now that we know how important it is to cut grass at the right length after overseeding, the next critical detail to think about is lawn mower settings. Most mowers have 6 settings which cut grass at different heights.

Numbers don’t necessarily correlate

It is a common mistake to assume that setting numbers match cutting height. That setting number 4, for instance, means the mower blade cuts grass at 4 inches. These numbers don’t correlate so it would be wrong to set the machine based on such an assumption.

The middle setting error

Many home owners who don’t want to get into these details assume that higher settings will cut too tall and the lower ones too short. They therefore opt for a middle setting. The error in this is that the middle setting in most mowers typically cuts too short.

Check the manual to confirm exactly what height correlates to specific settings.

Conclusion

Overseeding is an effective way to reclaim a once plush- looking lawn. That said, it must be done correctly. Knowing the right time to cut grass after overseeding is essential.

Experts generally advise waiting about a month so as to give the delicate roots time to establish themselves but the final decision should be made based on grass bade length. Make sure you know what type of seed you used and research to find out the exact cutting height recommended for it.

Be sure to check the settings on your lawn mower so you don’t just cut it close, but cut it just right.

FAQs

What is the best time of the year to overseed?

The best times to overseed are summer or early in the fall. This is when temperatures are favorable for seed germination and there is sufficient moisture and sunlight for seedlings to thrive. Overseeding at this time also ensures that grass is well established by the time temperatures drop drastically later in the year.

Must grass seed be covered to grow?

You don’t have to cover it. It will still grow even when not covered but it is beneficial to do so. Cover it with a layer of topsoil, compost or mulch. This helps to maintain moisture and could speed up germination.