Aeration and overseeding are like preparation and execution – without one, the other can’t achieve maximum results. We’ll show you how to aerate and overseed so that your grass receives the optimal environment for new growth.
It’s as simple as renting a core aerator, sprinkling the right grass seeds around, and watering until fresh shoots take hold firmly. We’ll also cover post-treatment tips – such as adding topsoil and fertilizer – that invite stronger, deeper roots, promoting a lusher lawn.
But where does one begin? Let’s walk through aerating and overseeding your lawn step by step.
Aerate and Overseed: Step-by-Step Guide
Step 1. Choose the Right Season
Before starting any new project, you must pick the right time. The ideal season for aerating and overseeding depends on the type of grass you have:
- Cool-Season Grass: Early fall is the best time (around mid-August to early October). However, if you miss this window and your lawn really needs some attention, early spring (between March and April) is the second-best time.
- Warm-Season Grass: Late spring to early summer is considered optimal. However, avoid overseeding during periods of extreme heat or drought.
Pro Tips:
- Choose the right grass seed. Live in the northern states? Cool-season grass will grow best. If you live in the southern states, opt for warm-season grass. If you live somewhere in the middle, both cool- and warm-season grass will grow well in your yard.
- To find out the ideal time to overseed, check your region’s first frost date history and then count back by six to eight weeks as a buffer. So, if frost usually shows up around October 15th, make sure you’re done overseeding by early September at the latest.
- Keep in mind that some grass varieties germinate faster than others. So, factor in the germination rate of your chosen grass variety when calculating your seeding deadline.
Step 2. Preparing the Lawn
The goal here is simple – create an ideal environment where seeds can easily come into contact with soil and sprout into lush grass.
- Clean-Up: Use a garden rake to clean up leaves, twigs, or other clutter from your lawn. This will loosen the top layer of soil and allow good seed-to-soil contact, which is very important for germination.
- Remove Thatch: Thatch is a layer of dead grass and roots that form on your lawn over time. Remove it using a thatch rake or power dethatcher. Remember, anything more than half an inch thick can obstruct water, air, and nutrients from reaching the seeds.
- Mow the Lawn: Give your grass a nice trim, but don’t cut it too short. Aim for the lower end of your grass type’s recommended mowing height without chopping off more than one-third of the grass blade. Also, bag the clippings. This allows the seed to reach the soil more easily.
- Watering (If Needed): Remember, your soil needs to be just a bit damp for optimum aeration. If the weather hasn’t been rainy lately, water your lawn generously a day or two before you start with aeration.
Pro Tip: The soil should be moist but not waterlogged so it’s easier for the core aerator prongs to penetrate deeply. A day after a good rain or watering would do the trick.
Step 3. Aerate the Lawn
Opt for a core aerator over a spike aerator.
While spike aerators merely create holes by pushing the soil into the ground, which can increase soil compaction, core aerators go a step further by extracting plugs of soil from the ground. This eases the soil, creating an easy pathway for air circulation and nutrients right down the roots. For more information on the differences, check out our article Core Aeration vs. Spike Aeration: What’s the Difference?
Here’s what to do:
- Call 811 before you dig. A professional will inspect your lawn and flag any underground utility lines for free.
- Whether you’re using a tow-behind aerator or a walk-behind aerator, start from one corner of your lawn and work methodically to the other side, much like mowing.
- Pay special attention to high-traffic areas, which are likely more compacted.
- If your soil is very compact or has a lot of clay, make multiple passes. The more holes, the better.
- Leave the extracted soil cores on the lawn. These will break down with rain or sprinkling and help to top-dress the lawn.
- While aerating, keep an eye out for sprinklers, shallow irrigation lines, or buried utility lines.
Do you still have lingering questions about lawn aeration? Perhaps the article How to Aerate a Lawn can help.
Step 4. Time to Overseed
Now that the lawn has been aerated and is boasting an ample amount of mini soil plugs looking like molehills, it’s time to overseed.
Here’s what to do:
- Using a manual, handheld, walk-behind seed spreader, or even your hand (a good option for small areas), scatter the seeds evenly across the lawn.
- Apply the seeds in a crisscross pattern, first lengthwise, then widthwise. This method guarantees that every inch gets proper coverage.
- Then double-check for bare spots and toss on a little more seed (if necessary).
- After spreading the seed, lightly rake it into the soil.
- Use the proper seeding rate for your grass type. Read the recommendations on the seed bag label.
- Roll the seeded area lightly to press the seeds into the soil. This step is optional but helps prevent the seeds from washing away.
Are you still scratching your head about how to overseed your lawn? We’ve got a simple and comprehensive eight-step guide just for that: How to Overseed a Lawn in 8 Simple Steps.
Step 5. Care for the Seedlings
Your new seeds and aerated soil require special care to thrive. The seeds need plenty of food, water, and protection to begin their germination journey. Here’s what to do after aeration and overseeding:
- Add Topdressing: Consider covering the seeds with compost topsoil or peat moss to improve soil content. This will also protect them from birds, help retain moisture, and provide an extra nutrition boost. However, avoid burying the seeds too deep.
- Water: With the seeds making cozy contact with your freshly aerated soil, now all you need to do is keep the grass moist and wait for nature to take its course. For the first two weeks post overseeding, lightly water your lawn at least once or twice a day (here’s our guide on How Often to Water Grass Seed).
- Fertilize: Applying a light starter fertilizer following overseeding can offer the young grass seeds the nutrients they need to grow strong and healthy. (Check out our article, Will Fertilizer Kill New Grass?, where we break down everything you need to nourish your grass confidently.) Follow up the fertilizer with a light watering.
- Postpone the Mowing: Wait until the new seedlings have reached a height of 3 to 4 inches before mowing.
- Limit Foot Traffic: Keep foot traffic to a minimum on your newly overseeded lawn for at least the first three weeks. As seedlings establish, they are delicate and can easily be uprooted by children or pets playing.
- Avoid Weed Control: Hold off on busting out any control products for the first 4 to 6 weeks after your lawn sprouts. The new grass friends are quite sensitive to herbicides. Meanwhile, yank out any weeds that dare to show up. Here’s a guide on When and How to Use Pre-Emergent Herbicides to Kill Your Lawn’s Weeds.
Why Aerate and Overseed?
Aerating and overseeding are a powerful combination for revitalizing your lawn. They work hand in hand, boosting each other’s effects.
Some of the main benefits of this power duo include:
- Optimal Seed-to-Soil Contact: Aerating involves making little holes in the soil, giving grass seeds a perfect settling spot to start sprouting.
- Shelter for Seeds: The aerated pockets help the seeds avoid harmful elements like intense sun or foot traffic – increasing their chances of successful growth.
- Improved Nutrient Uptake: Thanks to aeration, water, air, and nutrients can easily reach down into the soil, directly feeding new seedlings.
- Thicker, Healthier Lawn: Overseeding fills in bare patches and thickens the grass, while aeration promotes deeper root growth, resulting in a lush, resilient lawn.
FAQ About Aerating and Overseeding
How deep should you aerate a lawn?
The holes from aeration should be about 2 to 3 inches deep, half an inch in diameter, and 2 to 4 inches apart. Using a core aerator with hollow tines can help achieve these measurements and provide optimal conditions for overseeding.
What happens when you don’t aerate?
If your lawn is not regularly aerated, the soil becomes compacted, which limits the movement of water, nutrients, and air. Over time, this can lead to poor grass health or bare patches in your yard. Aeration invites better root growth and overall healthier turf by working against these negative effects of compaction.
What’s the difference between overseeding and reseeding?
Overseeding means spreading new grass seed over an existing lawn to fill in bare spots and thicken up the grass. On the other hand, reseeding refers to completely renovating a lawn by removing all the old grass and starting over with new seeds. Reseeding is necessary if a lawn is mostly weeds or bare soil.
Hire a Pro for Perfect Mowing
Aeration and overseeding are undoubtedly turf’s best friends. But they begin with mowing. Mowing is that critical first step before the aeration and overseeding process can start. Then you have to aerate correctly, spread the right seeds evenly, and water properly until fresh seedlings show up.
And remember, mow again only when the fresh seedlings have grown to a proper height.
Sounds like a big job? A local lawn care expert can handle the mowing for you, ensuring your lawn receives optimal care.
Main Photo Credit: Fokussiert / Adobe Stock / License