When to Mow After Overseeding

By Janine Soriano, Master of Science in Forestry, government environment researcher

Green and healthy turf is the pride of homeowners. However, there are instances when lawn grass may look under the weather. You can easily spot if something is wrong when grasses turn brown and patches of dirt appear, indicating grass cover is unhealthy. A recent disturbance, like wheel marks and holes appearing, would compel you to repair turf damage. Just like how need to get treatment humans when sick, your lawn also requires specific remedies to keep grasses growing healthily.

What overseeding is and its benefits

Overseeding, in its simplest terms, is sowing grass seeds over the existing turfgrass. Also known as reseeding, this cultural practice is not only applied on small, brown patches of dirt but can be also on the whole lawn itself. When working on landscapes, they use an aerator machine that punctures holes on the ground. Afterward, the seeds are planted in these holes so that they would have higher germination rates than simply by broadcast sowing. The holes create a better environment for seeds by protecting them from desiccation, especially during noontime.

Overseeding the lawn has a lot of benefits. First, it recruits new grass populations to increase the density of turf cover. When the lawn becomes crowded with turf, it will reduce the chances of weeds invading in empty spaces. This is important as allowing weeds to grow over the lawn invites pest problems. However, the choice of overseed species is a vital decision so that the turf species will outgrow competition from existing weeds. Another benefit is that dense grass cover also improves water and soil conservation. The rainwater is absorbed by the turf, thus reducing surface run-off. Ultimately, healthy turf cover prevents erosion of topsoil which contains the nutrients needed by the plants.

When to mow the lawn after overseeding

Upon overseeding, you might notice that the turfgrass grows unevenly. Obviously lawns look better if the turf is uniform and you might feel like mowing it as soon as possible, but it requires correct timing. Cutting too early would destroy the actively growing shoots, delaying the establishment of open patches on the lawn. A common practice is to mow grass that is about 3 inches high. This height is achieved at about a week or up to ten days if homeowners conducted regular watering. Mow overseeded lawns at one-third of the height so that grasses can recover. It is recommended to mow only on dry grass to prevent rupturing turf cover.

What to do after mowing an overseeded lawn

The general guidelines after mowing must be followed. The mowed grass must be maintained through regular watering so that grass can heal itself until the leaf blades are no longer tender. As much as possible, prevent physical disturbance while the turf recovers. Do not let any vehicles or large equipment pass through it or allow pets to dig up dirt on your lawn. Mowing can also be repeated regularly if turf grows too high.

Whenever you mow, make sure you clean up grass clippings on pathways and cemented surfaces. Leaving them in these places is unsightly and might lead to accidents. Clippings are best left decomposed on the mowed lawn. The grass clippings are a vital source of nitrogen and other minerals as added nutrition to the growing turf. Nitrogen is a mobile resource, thus ensuring its availability for the overseeded lawn is a must. This way, you can save money from buying fertilizers while securing food resources of microorganisms present in the soil. Nevertheless, there are instances where clippings must be put out. As a word of caution, applying mulch from weeds is not advisable because it will re-establish itself when conditions become favorable for its seeds to grow on the turf. Be careful not to put over clippings with evidence of disease symptoms if you do not want the turf species to become the new host of such pathogens. Bagging clippings are the best option in this case. Find a spot in your lawn where you will place a compost bin. Put the clipping waste in this container to allow them to rot. When the compost is ready, you can readily apply these on your lawn as an organic fertilizer.