How Short Should I Cut My Grass Before Aerating and Overseeding?

Aerating is a common and effective lawn care technique that is used by lawn care experts all over the country. Both warm-season grasses and cool-season grasses can benefit from this operation, but for lush green growth, you will need to do some lawn preparation before aerating.

Key Points:

  • Grass should be cut between 1.5 – 2 inches before aerating for best results.
  • Mowing too low or wrong turf can kill the crowns of the grass and require costly resodding.
  • Mowing low helps to uncover debris, irrigation pipes, and toys and assists with other lawn care practices like seeding, fertilization, dethatching, and core aerating.

Aerating will break up compact soil and help grass roots grow thicker, but only if the tines can penetrate deep enough into the soil.

To help the aerator’s metal tines, you can cut your lawn short before running an aeration machine across your turf. But the height you cut fescue lawns will be higher than the level you mow Bermuda grass, and this can be tricky to figure out.

Cutting grass too short or at the wrong time will kill the turf and require complete reseeding or resodding, both of which can be quite costly. Read on to find out how short to cut your grass before aerating your lawn.

What is a Good Mow Height before Aerating?

Cutting your grass to the lowest height that it can survive is recommended before using an aerator. In a mature, healthy lawn full of warm-season grasses with access to constant irrigation that could be as low as one inch high.

A good rule is to cut hot summer-loving turf to between 1½ inches to 2 inches, and cool-season turf should stay around 2 inches high. There are plenty of allowances based on grass types and climates, with northern lawns being a bit more forgiving for grass rebounding than the arid and hot conditions a grass blade must survive in the south.

Mowing the wrong turf 1 inch or lower can kill the crowns of the grass and cause scalping. This will kill your lawn and require you to have to resod the entire lawn, which is a costly operation. If the grass is left to grow taller than 2 inches, the aerator may not be able to create the deep plug needed to improve seed-to-soil contact and promote better root moisture and nutrient absorption.

After aerating, and especially if reseeding, allow the lawn to keep growing until it is 3 inches or higher to provide plenty of time for root growth and development. It is also a good idea to water deeply and infrequently to help fill the plug holes left by the solid tines with the deposited nutrient-rich plugs brought to the surface during aeration.

Prevent or reduce foot traffic while the lawn is regrowing after being cut short and aerator to speed up recovery time for the healthiest lawn.

Why Should I Mow Low?

There are lots of reasons to cut the grass short, and depending on your type of grass, mowing low can be an important technique to keep your lawn healthy at different times of the year. Larger lawns can build up a lot of grass clippings and leaf litter that, if left alone, could suffocate turf and lead to bare spots. Mowing low is an essential step in any of the lawn care efforts needed to grow a luxurious lawn.

Lawn machines are expensive and need some knowledge of the operation to use effectively and safely. Unexpected objects in the lawn, whether electrical lines, drainage pipes or even electric dog fences, can put even a lawn care professional in a dangerous situation.

Mowing the grass short prior to using a lawn service for aeration can help you find irrigation heads, sprinkler heads, or lawn furniture and toys. Irrigation pipes, usually just shallow irrigation lines, and rocks or partially buried concrete can all be damaged or damage the aerator and need to be marked with wire flags, not spray paint, which can be found at hardware stores.

Mowing low can also aid other lawn care practices, from the seeding process to fertilization. Dethatching and using core aerators become more effective when they can reach the debris and soil effortlessly, and low-cut turf is a key factor in making that possible.

Before seeding is a perfect time to mow low and water deeply to promote successful germination and prevent additional compaction by having to mow again before the roots are firmly developed.

Mow Heights and Lawn Care Techniques


For a green lawn that lasts year after year and outcompetes weeds, pests, and other invasive species, you will need to utilize a whole range of lawn care practices. Before busting out the machines needed to condition your entire lawn, it is a good idea to get your grass to the perfect height to complement your activity.

Below are some common lawn care techniques, the best height to cut the grass before beginning, and the befits of doing so; check it out.

TechniqueMow HeightBenefits
Aeration1 to 2 inches depending on the turf typeThe tines will reach deeper into the soil, making the lawn aeration more effective by reducing compaction and pulling more nutrients to the surface without destroying plant roots
Dethatching1 to 3 inches depending on the turf typeUnlike aeration, dethatching can be quite rough on turfs, and the extra strength provided by longer blades can help reduce tug damage, whereas rapidly propagating grass cut low allows the aerator to remove much more thatch than if the turf was left tall
Reseeding2 inchesSeeds benefit from some cover from the elements and protection from seed-eating critters, with taller grass aiding in moisture retention and a conducive micro-climate for grass seed to germinate in
Fertilizing2 inchesRoots that have been allowed to grow will absorb the nutrients faster, and the taller blades of grass protect the soil from evaporation before the fertilizer has had time to be absorbed into the soil, increasing the effectiveness of each application and reducing the need for repeat use
Drought Repair3 inchesAfter a drought, turf should be allowed to grow uncut until the brown starts to give way to green growth again, then you should cut at the highest level until the blades are green, at which time the appropriate seasonal height of 3 inches or so can be resumed
Winter Recovery3 inchesGrass coming back from winter should be allowed a growth spurt as rain, and warm weather increase and then can be cut short and left to grow to around 3 inches for the rest of the spring

When Should I Cut Grass Short?

Cutting grass short before frost or low winter temperatures is the only time of year it is extremely important to mow the grass short. Throughout the year, mowing grass short after the initial spring growth spurt, mid-fall after temperatures have dropped with moisture level increases, and before overseeding, aerating, or dethatching are good times to mow low as well.

If you follow the advised lowest cut height for your specific turf, you can take advantage of shortcuts for a healthy lawn all year long.

Cutting for Root Development

If you are cutting the grass low to encourage root development, you can help build soil fertility and allow excess moisture and nutrients to reach where the plants need them most. Letting grass grow and then cutting it short can allow for a more uniform growth across the entire lawn and reduce struggling for light or resources.

A full interwoven root system will help your turf weather drought conditions and harsh weather with less damage and reduced recovery time, and varying the cutting height aids the creation of the root system.

Cutting for Lawn Equipment

Mowing the grass to make other equipment more effective is an excellent strategy. If aerating or dethatching is part of your lawn care routine, then preparing the grass by cutting it short and adding the correct levels of moisture will make the job easier and more effective.

Trying to aerate in dry clay soil is nearly impossible, as is dethatching through 4-inch high turf, so take the right steps to make the job easier for you and your machines.

Cutting for Heat Absorption

In the spring, new turf sprouts and germinating grass seed benefits most from warm soil. It can be hard for the soft spring sun to heat the soil through thick layers of winter-wet turf, so cutting low when it is warm enough to do so is a good technique.

Once the grass is mowed and collected, the sun can heat the soil and promote faster blade growth. The increased heat early in spring can also help to reseed efforts and increase germination rates while decreasing germination time.

Can Cutting Grass Short Cause Issues?

There are some dangers to cutting grass short, especially if you have a slow-to-repair or crown-sensitive grass type. Once the crown of the grass is scalped, that area will die and be unable to come back. If the mower height happened to be too low, the entire lawn could be wiped out, and that would be a seriously expensive mistake.

Similarly, there can be times of the year that are not the right time to cut the grass short.

Cutting grass while it is dormant and when weather conditions are harsh can be equally disastrous. Lawns that are under heavy foot traffic need to have blades that can bend and repair, and low-cut grass can not prevent the root damage and compaction that will occur without that.

Lawn fertilization right before cutting grass short can lead to potential burns and other issues as healing and growth are impeded.

Frost is worse on low grass that is unable to shield the soil from frigid conditions and can lead to stunted growth, especially early in the spring. Cutting grass during a drought can immediately kill the blades and harm the roots that are unable to replace the liquids lost during chopping.

If you cut the grass short, make sure it is the right time, the right turf, and for the right reason, like to make lawn aerating more effective, and you will have a great-looking lawn all year long.