If your lawn has bare patches in need of reseeding, begin by mowing the grass to about 2.5 inches (6 cm) in height. Then, use a core aerator to aerate the bare patches in your lawn. Next, spread a lawn starter fertilizer so your new grass gets a growth boost. Follow this up by spreading a thin layer of compost over the bare areas in your lawn. Once this is done, spread your grass seed and rake the compost lightly over it. All that’s left to do is water your grass seed and wait until your grass is tall enough for regular mowing.
Can You Put Grass Seed on Top of an Existing Lawn?
You can reseed bare patches in an existing lawn and fill in the sparse grass. This process is commonly referred to as “overseeding.” When overseeding, it’s important to use the same variety of grass that is already growing in your lawn. Because different varieties of grass have different colors and growth patterns, it’s essential to know what species of grass is currently growing in your yard. That way, you can buy grass seed that matches that variety.
- Spreading grass seed on an existing lawn (called “overseeding”) is common and effective.
- When purchasing grass seed, make sure it is the same species as the grass currently growing in your lawn.
- Some species of grass—such as St. Augustine—cannot be grown from seed. They must be planted from sod or grass plugs.
It’s important to note that some species of grass cannot be reseeded. St. Augustine grass is not typically sold as seed. Instead, it is sold as sod or soil plugs. If you are growing St. Augustine grass, you won’t be able to reseed your yard, but you can patch bare areas with sod.
When Should You Reseed Your Patchy Lawn?
Depending on the variety of grass you’re growing, spring or fall is the best time to reseed your lawn. If you are growing cool-season grass, fall is the best time to overseed your lawn in the northeast or midwest. Cool-season grasses include Kentucky Bluegrass, Ryegrass, and Fescue. They experience their strongest growth in fall, when temperatures dip down to 70℉ (21℃). Because they struggle to grow in the summer heat, you won’t get great results by overseeding these grasses in spring.
- If you are growing cool season grasses (Kentucky Bluegrass, Fescue, Perennial Ryegrass) fall is the best time to seed your lawn.
- If you are growing warm season grass (Bermuda, Zoysia, Centipede) then spring is the ideal time to seed.
If you are growing warm-season grass, such as Bermuda, Centipede, or Zoysia, spring is the best time to reseed the bare patches in your lawn. Warm-season grasses grow best in spring and summer. So, it’s best to overseed once temperatures rise to 80℉ (27℃) in spring.
7 Steps to Fix Your Patchy Lawn
In order to repair a patchy lawn, it’s essential to prepare the soil before reseeding. Grass seeds spread on top of your lawn without any prep work will not sprout or survive. Here’s how to get the most out of your seeds when reseeding a lawn with patchy grass.
Mow Your Existing Grass
Begin by mowing your lawn to a height of 2.5 inches (6 cm). Long grass will block grass seed you spread from making good soil contact. So, cutting your lawn to a manageable height will help more of your grass seed sprout.
Aerate the Lawn
Before overseeding, aerate the bare patches of your lawn with a core aerator. You can rent a core aerator for use in your yard. Core aerators loosen compacted soil, making it much easier for grass seeds to take root. Thoroughly aerate the bare patches in your lawn, then leave the soil plugs on the surface to break down naturally.
Provide Lawn Starter Fertilizer
Before seeding, spread this lawn starter fertilizer on the dead grass areas in your lawn. This fertilizer contains nutrients essential for grass seedlings to develop strong roots and long blades. The holes left by aeration allow the fertilizer to work itself into the upper layer of soil. This ensures that your new grass seeds grow into healthy grass. It’s best to apply fertilizer before spreading any grass seed.
- Great starter fertilizer for new seed or sod.
- You can also use Pennington UltraGreen for overseeding or on an existing lawn.
- 5% Iron promotes a deep, thick, lush lawn.
Top Dress the Soil with Compost
After aeration, spread a thin layer of compost on the areas that you will be overseeding. ¼ inch (6 mm) of compost is enough. You want just enough compost to cover the soil, but you do not want to cover your existing grass. It’s a good idea to use a garden rake to evenly distribute the compost over the area you will be seeding.
Spread Grass Seed
Once your compost is in place, spread grass seed onto the bare areas. For most yards, you can spread grass seed by hand. Follow the bag rates for the amount of grass seed (by weight) per square foot. Then, use your rake to gently rake the compost over the seed. This will insulate and protect the grass seed, ensuring more of your seeds sprout.
You must keep the soil moist in order to encourage grass seed germination and ensure you get thick grass growth. To do this, water the overseeded areas of your lawn two times per day for the first week. Use our guide for watering new grass seed. Water 5–10 minutes per watering session, two times per day until the grass seed sprouts. Once you see new sprouts coming up, you can reduce watering to twice per week.
Wait Before Mowing New Grass
Mowing your new lawn too soon can destroy young grass sprouts. The suction of the mower blades can tear grass seedlings up from the roots. Plus, cutting new grass can cause serious damage. To prevent this, wait until your new grass is about 4 inches (10 cm) tall before mowing for the first time. Mow to about 3.5 inches (9 cm) in height. Then, continue weekly mowing as your new grass blends with your existing lawn.
What is the Best Way to Reseed a Patchy Lawn?
The best want to reseed dead patches in your lawn is to
- Determine the grass type you are growing and purchase grass seed to match.
- Mow your existing grass to 2.5 inches (6 cm) tall.
- Use a core aerator to loosen soil in the dead patches.
- Apply a starter fertilizer to the areas you will overseed.
- Spread a 0.25 inch (6 mm) layer of compost over the dead patches.
- Cast your grass seed on the dead patches and rake the compost to cover the seeds.
- Water the seeds twice daily until the grass sprouts.
- Wait to mow until your new grass is 4 inches (10 cm) tall.
By preparing the soil, adding fertilizer and compost, and providing frequent watering, your new grass will come up strong. By overseeding the dead patches in your yard, you will transform your entire lawn for the better.