Weeds can be frustrating. For many of us, battling weeds is the most time consuming and difficult part of our lawn care routine. A weed covered lawn can make seeding seem like an impossible task, but weeds don’t have to stop you from reaping the benefits of overseeding your lawn. While it does take a little extra prep, there are some tried and true methods to fighting weeds and sowing seeds. Before you know it, you’ll be growing thick, healthy, new grass where unwanted weeds used to be.
Unfortunately, weeds are equipped to outcompete grass. They produce seed rapidly, disperse seed widely, and are able to tolerate less desirable conditions. Plus, their seed can remain viable in the soil for years. By their nature, they will always steal resources from your lawn. However, weeds aren’t all bad, they do have some positive qualities, including the fact that they are pollinator -friendly plants. But in your lawn, an abundance of weeds can be a real issue. Growing resilient blends of grass species is a great way to fight back against weeds without negatively impacting the ecosystem. Every rich, green blade of grass begins with a seed.
When it comes to seeding a weed-covered lawn, there are two options. You can either spot treat the weeds or thin them. Either way it is important to free up some space for the fresh grass seed to germinate. Both of these approaches have benefits, so it comes down to picking the right option for your lawn.
Treat then seed
Depending on the size and location of your weed issue, use a weed killer like Sunday Weed Warrior Concentrate or Dandelion Doom Concentrate to eliminate weeds. Once the weeds are dead, use a weeding tool to pull them out by the root, making sure to remove the entire root system. After removing weeds throughout the lawn, seed in bare patches and overseed the entire lawn. Then water to help the new seed germinate.
Mow low and then seed
In a very heavily weeded lawn, mowing 1-2 inches shorter than normal can remove 50-65% of leaf tissue, which helps grass grow better by opening the grass ‘canopy’ and exposing bare soil, giving grass seeds space to germinate. This process is also called “fraising the canopy.” The key is opening the canopy of your lawn to allow seed to reach the soil, and then seed in heavily. A week or so after seeding, mow short once again to cut back any new weed growth which will help seeds compete against existing weeds.
Choosing a method depends on preference and size of weed issue, but either way, we recommend ‘thinning the lawn’ for extremely weedy lawns as it may reduce labor and require less product. You can also attempt a combination approach of the two options for lawns with harder-to-remove weeds.
Once the grass seed hits the ground, it is important to carry out appropriate seeding care. For germination, the seed needs to reach the soil and get plenty of water. Make sure to keep the overseeded or patched areas moist for at least 10 days, or until you see ¾” of growth in the patched area or the lawn is at least 60% green. You can continue hand-pulling or mowing weeds while waiting for germination just be extra careful not to disrupt the newly seeded area. Reducing foot traffic and making sure to weed before watering will help ensure that emerging seed gets the nutrients and space they need to grow.
There are a lot of factors that impact weed growth. Everything from seasonality, to moisture, soil health, and general stress can lead to an overly weedy lawn. The secret is looking at more than just the weeds you see and identifying the cause beneath. More times than not, compacted soil or poor drainage is the root of weed issues. If you simply kill the weeds without solving the underlying cause, you will never truly solve the problem and likely face weeds year after year. Soil matters, and healthy soil structure is crucial for a healthy lawn. After all, lawn health begins in the ground.