Planting grass seed onto an existing lawn is going to improve the grass that grows thinly. Plus, it can keep the warm-season lawn from turning brown when winter arrives. It’s often called overseeding, and sowing grass seed is generally part of lawn renovations.

Along with that, you should control weeds, use fertilizer, and improve the soil conditions. It’s possible to over-seed the lawn in early fall or spring, but fall is often the better time. Cool and wet weather provides the right conditions for the grass to grow.

If you’re overseeding the warm-season lawn with some cool-season grass to have a green lawn in winter, you’ve got to over-seed in the fall months. Learn how to plant grass seed on an existing lawn with these steps:

Control Weeds

Weeds are going to compete with the grass for nutrients, light, and water. Therefore, you should remove them before trying to over-seed the existing lawn. Get rid of small weeds by pulling them with your hands or using a weeding tool to dig them up.

Large weeds with deep roots should be pulled using a special weed popper tool. If the lawn is infested with the weeds, apply a lawn herbicide to the area about five to seven days before you sow the grass seed.

When you apply herbicides before you over-seed the lawn, let it grow a bit more than normal. This ensures that the broadleaf weeds have bigger leaves on the top so that it catches more of the herbicide. Choose the right herbicide based on the type of turfgrass and weeds you have.

Usually, you want a product that contains 0.22 percent of MCPP-p, 0.1 percent of quinclorac, 0.05 percent of dicamba, and 0.12 percent of 2,4-D. These ingredients are going to control most broadleaf weeds for many lawns.

When the temperatures are over 45 degrees Fahrenheit (7°C) and the day is still and dry, use the product. Make sure it’s not over 90 degrees Fahrenheit (32°C). Wear protecting clothes (long sleeves and pants), gloves, safety goggles, and more.

Then, lightly spray each weed with the product. Make sure to pay attention to the manufacturer’s instructions for the best results.

Prepare the Lawn

To prepare your lawn for the overseeding, make sure to aerate, dethatch, and mow. Just before you plant grass seed on an existing lawn and after applying herbicide, mow your grass at the mower’s lowest setting. This is going to ensure that the blades of grass are cut right above soil level.

Rake up any grass clippings and check for thatch. This is a layer of moss, plant debris, and dried lawn clippings. If you’ve got a layer of thatch thicker than 1/3 inch, use a dethatcher or hard rake the lawn.

Remove roughly half of the thatch from the entire lawn and let the rest stay as mulch. When you use a dethatcher, the soil is cultivated and prepared for the lawn grass establishment. Use an aerator to remove soil plugs and break it up so that water and air can get to the roots of your grass.

Sow the Seeds

The grass variety you use determines the right rate for sowing the grass. For example, annual ryegrass is cool-season and offers winter color for warm-season lawns. You sow it at rates of 7 to 9 pounds for every 1,000 square feet.

On the other hand, perennial ryegrass is a tougher grass for more high-traffic areas. Therefore, you can sow it at a rate of up to 6 to 8 pounds for every 1,000 square feet.

Both types are quite invasive. In wet weather and the right aftercare, about 95 percent of the grass seeds should grow well and sprout. In dryer weather and in poor conditions, consider sowing at a higher rate.

Sow your grass seed with a broadcast, drop, or handheld spreader. Divide your seed into two piles so that you can make two even passes over your lawn. One should go up and down, while the other goes from side to side.

That way, there is even coverage over the entire lawn. Sow the grass seed up to three more times so that it’s thicker on those bare patches.

Irrigating and Fertilizing

Grass seeds require plenty of fertilizer and water to grow the best. Before you plant the grass seed, apply some lawn fertilizer based on soil test reports and recommendations for your area.

Rake the soil so that the fertilizer gets in. Then, water your lawn so that the soil is moist 4 inches deep.

Conclusion

Learning how to plant grass seed on an existing lawn is essential. That way, you can have beautiful greenery throughout the year or get thicker, more luxurious grass. The steps for planting grass seed actually require you to weed, fertilize, and know your soil.

From there, it’s easy to seed the lawn with the right product. Make sure you’re reading the manufacturer’s label to know how much to use. Don’t skimp on the product, or you may find that it doesn’t do the best.