Overseed your lawn in the fall after killing weeds in late summer. If you’re late, scalp the weedy lawn, rake away all the debris, and spread grass seed. Some weeds will germinate and grow with the grass, but you can control them using a post-emergent herbicide before they spread further. How to Reseed a Lawn With Weeds. If you are faced with a neglected lawn that’s partially dead and is being taken over by weeds, you may be able to renovate it. Restoring a deteriorated lawn may be possible if the weeds and dead spots cover less than 40 percent of the lawn area. Renovation of a weedy lawn involves more … How to Restore a Lawn Full of Weeds If your lawn is patchy and full of weeds, it will never be the envy of the neighborhood. What you’re after is a lush, green lawn with even grass and no
Overseeding a Lawn with Weeds: Should You Kill Weeds First?
A lawn full of weeds can become even more problematic if you don’t overseed the right way. Overseeding is meant to renew your lawn, fill in any bare spots, and make the turf dense. But, when your lawn is full of weeds, should you go ahead and overseed without killing weeds first?
Overseed your lawn in the fall after killing weeds in late summer. If you’re late, scalp the weedy lawn, rake away all the debris, and spread grass seed. Some weeds will germinate and grow with the grass, but you can control them using a post-emergent herbicide before they spread further.
It is not a good idea to plant and grow new grass over weeds because weeds compete for nutrients and water in the soil, which leads to poor germination and growth of the newly planted grass.
I invite you to join our Lawn Care Group where we all interact, ask, and answer peer questions.
Should I Kill Weeds Before Overseeding?
Kill and remove weeds from your lawn at least 6 weeks before overseeding if you’re using a post-emergent herbicide. Alternatively, remove weeds by hand-pulling manually. Weed killers will affect the seed germination, so, allow enough time as indicated on the product label before planting grass seed.
Since the best time to overseed most lawns is fall, late summer is a good time to put down a post-emergent weed killer. By the time fall comes, it will be at least 4-6 weeks since you applied a weed killer, which is safe for planting grass seed.
How to Overseed a Weedy Lawn
It is best to kill weeds first before overseeding.
Weeds like bare spots and can continue to spread and invade your lawn if you don’t do anything about them. That’s why overseeding helps control them by making your lawn thicker and fuller, and able to choke out weeds.
Overseeding is time and cost-effective, as you don’t have to till and tear apart your lawn. Instead, you’re breathing life back by adding more grass seeds on top of an existing lawn. If done right, this technique lets you grow enough lush lawn that fills in the bare or thin patches in your yard, leaving no room for weeds to grow.
Here’s how to overseed a lawn with weeds:
1. Pull out the weeds manually
Remove weeds from your lawn manually using a weed puller. Pulling weeds out by hand is highly recommended especially if the weeds are grown and visible. Do not apply herbicides on your lawn before overseeding as this can cause poor germination of grass seed.
If you prefer using a weed killer before overseeding, do so early enough to allow time for the herbicide to break down completely before spreading grass seed. Most pre-emergents and post-emergent herbicides have indicated waiting periods before you plant grass seed.
Here’s how to pull out weeds by hand:
- Water your lawn deeply to make the soil soft.
- Pull out weeds by hand or using a weed puller.
- Throw the weeds away from your yard.
In some cases, you may not need to apply a weed killer as weeds like crabgrass usually die off as the weather becomes cooler. If you have annual weeds, just overseed your lawn with weeds late in the fall and allow the new grass to grow. By the time spring comes, your lawn will grow thick and full enough to choke most annual grassy weeds.
2. Mow the lawn on the lowest setting
Set your mower to the lowest setting possible in order to scalp the lawn you want to overseed. Scalping your lawn helps improve the seed-to-soil contact that in turn improves the rate of seed germination. Set your lawn mower’s deck as low as possible – though any setting between 1.5 and 2 inches would be a good option to consider if the lawn does not have too many weeds.
- If your lawn is level, you can set the mowing deck as low as 1 inch from the ground.
- If your lawn is bumpy, set the blades a little higher – up to 2 inches to prevent damaging the blades.
Pro tip: Always bag clippings if your lawn has weeds that have gone to seed to prevent spreading weed seeds all over your yard and worsening the problem.
It is also a good idea, in my experience, to mow right before the rainy week to keep the lawn moist. It makes my mowing job a lot easier as the grass is soft and the thatch easy to remove right before overseeding weedy lawns.
3. Remove grass clippings
Use a rake to remove grass clippings and other debris that’s covering the soil. The process of raking also helps loosen up the top soil in your yard.
If you mowed a little higher, you might have a lot of thatch remaining on the soil surface. Use a heavy duty rake to remove any debris that can prevent your grass seed from staying in contact with the soil for germination.
A good rake can also help you remove any moss that may be growing under the grass in your lawn.
4. Dethatch the lawn
A thick layer of thatch can also cause seed to soil contact problems. Use a dethatcher to break down the thick thatch and then collect the loosened-up trash bag and throw it away on your compost.
Alternatively, run a power rake all over the weedy lawn to loosen up any thatch and tangled-up grass.
When I have a large weedy lawn to overseed, I find it helpful to rent a slit seeder to complete the task in the shortest time possible.
5. Aerate the lawn
By the time it is fall, the soil is usually compacted already, which is why the grass in your yard is growing slowly while the weeds grow faster. After removing the weeds, mowing, and dethatching, core aerate the lawn to allow air, water, and nutrients to be easily accessed in the root zone.
The cores created in the yard will also allow for better seed-to-soil contact as soon as you overseed. This process is better than just sprinkling grass all over the lawn because it improves the rate of seed germination.
6: Spread the grass Seed
Spread grass seed over the prepared area using a lawn spreader. Follow the recommended spreader settings for the type and variety of grass seed you’re overseeding your lawn with to ensure you’ve put down enough make your turf thick and full the next season.
Pro tip: Spread a thin layer of straw to cover grass seed and prevent birds from causing damage. You can also use bird deterrents if you don’t want to cover the grass seed.
For the best results, plant one-half of the grass seeds in one direction and the other half in the opposite direction. I recommend using a lawn spreader for even distribution of the seeds.
Also, you need to make sure the seeds have a good contact with the soil because this helps with proper germination and enhances growth. You can use a water-filled roller or the back of metal rake to establish the recommended contact between the soil and your grass seeds.
7. Gently rake in the grass seed
Raking is important as it helps the seeds come into contact with the soil to germinate properly. If you used a spreader or simply broadcast the seeds with your hand, the grass seed isn’t in proper contact with the soil.
Lightly rake in the seed over the overseeded area to improve contact and promote faster germination. Raking will also prevent water from washing away seeds in your lawn when you irrigate.
8. Water your overseeded lawn lightly
Water the overseeded area lightly to keep the soil moist enough for the grass seeds to germinate and grow. Do not use a heavy sprinkler because it can easily erode the seeds away from the desired area.
Here’s a video on how to prepare and overseed a lawn with weeds:
How to Control Weeds after Overseeding
Weeds may sprout in your lawn soon after your grass seed starts to germinate. At this time, do not apply herbicides yet. Applying herbicides too soon can kill or weaken the young grass shoots.
Wait until the roots have established and the crown matured enough to withstand the strength and effect of the chemicals.
Also, instead of using equipment such as a power rake, which disrupts lawn surfaces, use less disruptive tools such as a hand rake, as they cause less disruption and don’t leave bare patches on the lawn.
Overseed your lawn at the right time to reduce weed competition and enhance the dramatic, successful growth of the overseeding process. You can overseed cool season turf grasses between mid-August and mid-September as a way to fix a weedy yard. These are favorable times for their germination and establishment.
Can I overseed after weed and feed?
It is not recommended to overseed your lawn after applying weed and feed fertilizer. This type of lawn food contains herbicides that can inhibit germination of both grass and weed seeds. If you’ve just put down weed and feed, wait at least 6 weeks before sowing grass seed.
Read the weed and feed product label for the recommended time to wait before reseeding your lawn. Follow the instructions to ensure you achieve a high germination rate when overseeding a weedy yard.
While fall is the perfect time to overseed your lawn and encourage weed control, there are other seasons to overseed provided you understand the risks.
You can overseed in the early spring, but make sure the lawn is well drained for the best results. Weed competition is more progressive and intense as spring progresses. So unless you time the overseeding period before weed germination in spring, doing so at this time may not be effective.
Summer is the least desirable time to overseed your lawn especially if it has weeds. In early summer, the conditions are so hot that there’s a huge demand for irrigation for proper overseeding to be possible. This is also the time when broadleaf weeds tend to thrive, and therefore your overseeding efforts are likely to fail.
Overseeding will make your lawn fuller, and thicker; and improve its pest, disease, and weed resistance. Remember, care for and maintain your lawn after reviving its look and density. Some tips include sufficient watering, proper fertilization, consistent weeding, foot traffic control, and proper mowing.
How to Reseed a Lawn With Weeds
If you are faced with a neglected lawn that’s partially dead and is being taken over by weeds, you may be able to renovate it. Restoring a deteriorated lawn may be possible if the weeds and dead spots cover less than 40 percent of the lawn area. Renovation of a weedy lawn involves more than just mowing down the weeds and throwing some grass seed over the lawn.
Kill the Weeds
The best time for lawn renovation throughout the U.S. is mid-August to mid-September. Most weeds have not yet dropped their seeds and there will be little new weed growth. Also, reseeding at this time will give the new grass a chance to establish itself before going dormant for winter. Get rid of the weeds by manually pulling up large, spreading weeds. Follow up by applying a selective herbicide product that kills common broadleaf lawn weeds while not harming grass. For tough grassy weeds, like quack grass or crabgrass, use a nonselective herbicide such as glyphosate on the spots where these weeds have established themselves. Normally, all weeds will be dead within two weeks. Apply another herbicide dose in three weeks to get newly sprouted weeds.
Water the Site
If you have had a dry summer with below-normal rainfall, you need to replenish soil moisture before preparing a seedbed. Give the entire lawn a thorough watering, soaking until water has penetrated to a depth of at least 6 inches, then allow the surface to dry for a day or two before starting soil preparation.
Most deteriorated lawns have a built-up layer of dead and partially rotted grass stems, roots and rhizomes just below the green grass leaves. This is known as thatch, and it must be removed before reseeding so water and fertilizer can reach the new seed. For small lawns, you can remove thatch with a garden rake. For large areas, go over the lawn with a power dethatcher, also known as a vertical mower or power rake. These machines can be rented from garden centers. Remove the clumps of matter left by the machine with a garden rake and level the soil by raking it.
Feed & Seed
The soil nutrients most important to healthy grass plants are nitrogen, potassium and phosphorous. Supply these nutrients by applying a commercial fertilizer formulated for starting lawns and lightly rake it into the soil before you reseed. Buy a grass-seed blend suited to your climate and local conditions and spread it over the lawn with a drop spreader or rotary spreader. Absent a different recommendation from the grass-seed grower, spread the seed at a rate of 2 pounds per 1,000 square feet on a lawn with substantial plots of live grass and 3 pounds per 1,000 square feet on bare soil. Water lightly once or twice a day to keep soil moist but not sopping wet. Don’t mow until the new grass gets 3.5 inches tall.
- University of Minnesota Extension: Lawn Renovation
- Southern States Cooperative: Reseeding Your Existing Lawn
Herb Kirchhoff has more than three decades of hands-on experience as an avid garden hobbyist and home handyman. Since retiring from the news business in 2008, Kirchhoff takes care of a 12-acre rural Michigan lakefront property and applies his experience to his vegetable and flower gardens and home repair and renovation projects.
How to Restore a Lawn Full of Weeds
If your lawn is patchy and full of weeds, it will never be the envy of the neighborhood. What you’re after is a lush, green lawn with even grass and no dandelions poking their way through. That may sound hard to achieve, but it isn’t too difficult if you follow these steps.
If you only have a few pesky weeds punctuating your lawn, you may be able to dig them up by hand—paying careful attention to make sure you get them roots and all. But if your lawn is overrun with weeds, you may need to start from scratch. Here’s our how-to guide on restoring a lawn full of weeds.
Once your lawn is nice and green, we recommend hiring a professional lawn care company to help you maintain it to keep it weed-free. Our top recommendation goes to industry leader TruGreen.
Restoring a Lawn Full of Weeds in 10 Steps
Step 1: Identify the Weeds You Have
In order to make a successful game plan, you’ll need to know just what kind of weeds you’re dealing with. Weed treatments are designed to target specific weeds, so what may work on your broadleaf weeds may leave your grass-like weeds A-OK.
Weeds come in multiple categories, either broadleaf, grass-like, or grassy.
- Appearance: Broad, flat leaves
- Common types: Clover, ground ivy, dandelions, chickweed
- Appearance: Similar to grass, with hollow leaves in a triangular or tube shape
- Common types: Nutsedge, wild garlic, wild onion
- Appearance: Resembles grass, grows one leaf at a time
- Common types: Foxtail, annual bluegrass, quackgrass, crabgrass
Weeds can be broken down further into categories based on their life cycle—annual, biennial, or perennial.
- Annual: Produces seeds during one season only
- Biennial: Produces seeds during two back-to-back seasons
- Perennial: Produces seeds over many seasons
Step 2: Select a Proper Herbicide
Next, it’s time to select the proper weed treatment based on both weed classification and the stage in their life cycle. Pre-emergent herbicides tackle weed issues before they spring up. Post-emergent herbicides target established weeds.
Keep in mind that herbicides can kill whatever plant life they come into contact with—even if the label says otherwise—so handle with care. If your aim is to re-establish your lawn, as we recommend, killing your existing, thinning grass isn’t a big deal, since you will need to start fresh anyway.
Step 3: Apply the Treatment
For this step, it’s crucial that you follow the directions to the letter. Make sure you apply the proper product at the proper time. It’s a good idea to check out the forecast beforehand, since you don’t want any storms to wash away your herbicide.
*First application. See quote for terms and conditions.
Step 4: Wait It Out
How soon you can plant seed depends on the type of weed treatment you choose. Pre-emergent herbicides will prevent grass seeds from growing just as much as weed seeds, so it would be no good to sow seeds immediately after.
Depending on the type of weed treatment you choose, you may need to wait for up to four weeks. You can ask your local garden center for information about when it’s safe to plant.
Step 5: Rake and Till
Once the weeds—and grass, if applicable—turn brown, it’s time to bust out your rake. Rake up as much of the weeds as you can. Use your tilling fork to pull any extra weeds out and till the soil to prepare it for your amendments and seed.
Step 6: Dethatch and Aerate
Aerating your lawn can help break up thatch, the layer of decomposing organic matter between your lawn’s soil and grass blades. Thatch can be beneficial, since it can make your lawn more resilient and provide insulation from extreme temperatures and changes in soil moisture. But if it gets over a half-inch in thickness, it can cause root damage, including root rot.
Your raking and tilling from the previous step can help with dethatching, but you can also use a dethatching rake if the layer is too excessive.
Aeration improves your grassroots’ access to air, nutrients, and water. Use a spike or core aerator to break up the soil. If you use a core aerator, be sure to make two to three passes in different directions. Allow the plugs of soil you remove to decompose on top of your soil layer rather than remove them.
Step 7: Amend the Soil
Now, you can apply your soil amendment to ready your soil for the grass seed or sod.
Step 8: Lay Down Seed or Sod
You have a choice ahead of you. Do you want to lay down seed or sod? There are pros and cons to each.
- Pros: Less expensive, more variety
- Cons: Takes longer to germinate, can only lay at certain times of year depending on grass type
- Pros: Instant grass, can lay any time of year, requires little maintenance
- Cons: More costly, less variety in grass can mean less healthy lawn overall
To prepare the soil after either method, make sure you till it down to roughly 6 to 8 inches.
First, you need to choose the right type of seed for your lawn. That will depend on the region you live in—one that needs cool-season grasses, warm-season grasses, or a transition zone that allows more flexibility. After you determine which category you need, you can select specific grasses that may have attributes you’re after, like heat- or drought-resistance.
To seed your lawn, lay down approximately 1 inch of topsoil, then use a spreader to apply the seed to the soil.
We recommend using two different types of spreaders. For the majority of the work, you should use a broadcast spreader because they distribute seed evenly, allowing for thorough coverage. But you’ll want to use a drop spreader around the edges of garden beds to make sure you don’t inadvertently drop seed into them.
Always set the spreader to half the recommended drop rate and spread the seed in one direction, then one or two more in different directions to make sure the coverage is nice and even. You don’t want your lawn to have weird patterns or stripes.
Applying the right amount of seed is key. As a general rule of thumb, apply roughly 15 seeds per each square inch, then rake over the seed.
Top the seed with top dressing no greater than ¼ inch thick.
Then, it’s time to add starter fertilizer. Your best bet is to use a starter fertilizer high in phosphorus. However, due to concerns about water pollution, many states prohibit the use of phosphorus in fertilizers. Some states may allow phosphorus in fertilizers for establishing new lawns. If so, you’ll find fertilizers labeled “new lawn” or “starter fertilizer.”
Step 9: Water Your Lawn
Deep, infrequent watering can help establish your lawn by allowing it to grow deep roots, which can compete against weeds. Try to water your lawn about twice a week, in the morning before the heat of the day sets in. Lawns typically need about 1.5 inches of water per week, but that could vary based on the climate you live in and the type of grass seed you chose.
Step 10: Maintain Your Lawn
Proper maintenance is critical if you want your newly established lawn to stay weed-free. Mow at either the highest or second-highest setting. Vigorous grass won’t be choked out by weeds. Fertilize your lawn as needed to help it thrive.