A healthy and lush green lawn is beneficial for any home or business, but many people fail to realize that it’s far more achievable than you think. In fact, all you have to do is master the overseeing process. Fortunately, the experts at ISR Gardening have years of experience fine-tuning their overseeing process. And if you stick to the following guide on how to oversee a lawn, you can also master this practice and begin seeing improved results.

How to overseed a lawn

Overseeding is simply applying grass seed to an existing lawn. As a lawn age, it’s common for it to begin thinning especially if the lawn sees a lot of foot traffic. But this is where overseeding can help. It’s necessary to be mindful of the time of year you plan on overseeding.

If you are working with cool-season grass – such as Kentucky bluegrass, fescue, and perennial ryegrass – it’s ideal to be overseeded in the fall. This is because the soil is still warm enough to promote seed germination while the cool air helps to develop a strong root system.


When working with warm-season grass like Bermuda, Saint Augustine, zoysia, or centipede, it’s recommended to carry out overseeding in spring or early summer. You will also need a consistent watering schedule. This will help the grass establish before the summer heatwave arrives.

Prep and Plan – there are a few tools you’ll need. You need a lawnmower, an aerator, a spreader, and a thatch rake. All fertilization should be halted a month prior to overseeding. Next, measure your lawn size to determine length and width. Multiply these two numbers together to get your square footage.

Mow & Dethatch – Cut your grass as short as possible and collect all clippings in order for new seed to reach the soil while also getting the needed water and sunlight. Using your thatch rake, loosen the soil while removing any clippings and debris. Loosening the soil allows it to take the seed.

Thatch is made up of stems, dead grass blades, and stems mixing with live plants. A thick layer can cause disease and even encourage insect issues. In order to properly dethatch, rake your grass in one direction before raking in the opposite direction.

Aerate your lawn – aerating your lawn is beneficial in a number of ways. This treatment helps to loosen soil which allows air and water to reach the roots of the grass. This also allows your new grass seed to grow quicker and thicker. Aeration is especially needed if the lawn is subject to heavy usage. In order to aerate a lawn, move across the yard in straight lines and ensure to cover the entirety of the lawn.

Next, do a second treatment, but this time work in a perpendicular motion to the original one. This will properly ensure to break up any compacted soil. Leave the soil plugs that are left in the machine’s wake to break apart over the coming weeks.

Reseed bare spots – another nuisance that overseeding helps to eradicate are bare spots in the grass. In order to tackle this problem, cover any of the bare spots with a layer of topsoil before you begin to overseed. This is dually beneficial because it promotes grass growth while also improving soil health.

When facing a bare spot in an area with drainage issues, lay down a thin layer of sand first – this helps the seed germinate at a quicker rate while also promoting a robust root system.

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Overseed and fertilize – there are a few things to keep in mind during the overseeding and fertilization process. First, spread the seed evenly across the yard with the help of a handheld spreader, broadcast spreader, or drop spreader. Make sure that you select a fertilizer that works best for the type of grass you’re growing. As soon as you finish the overseeding treatment, conduct a light watering.

And for the first few weeks after this process, it’s important to water the yard three to four times a day. This will assist the seeds during the germination stage. Finally, when the grass grows to an inch in length, you can dial back the watering to once a day.

Overseeding lawn maintenance

The best practice to maintain your lawn after you are overseeding is to cut the grass at the two-inch mark for the remainder of the year. It’s also important to ensure there’s no moisture on the lawn when you mow.

After you lay the seed, it’s recommended to fertilize at the six-week mark – apply a quick-release nitrogen type, and use one pound for every one thousand feet of lawn. For instance, if your yard is 2,500 square feet, you’d need two and a half pounds of fertilizer. Repeat for an additional six weeks or when the package dictates.

Contact Us

There you have it – the complete guide to reseeding your lawn thanks to the trusted professionals at ISR Gardening. This process is a great way to maintain a healthy lawn, fill in any bare spots, and even repair the damage. We consider ourselves the overseeding lawn professionals for a reason at ISR Gardening, and that’s because we can recommend the best blend of grass seed for your lawn. Contact us today to set up your free consultation and get more information about when to oversee lawns in Ontario.