Learn how to avoid common mistakes when planting grass seed for a more full, lush, vibrant lawn. Lawn myth busting: Skip spring ‘weed and feed’ Editors note: Rossi is a turf specialist and associate professor in the Department of Horticulture, Cornell University. This is the first in a 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 Avoid Common Grass Seed Mistakes
Creating a lush, vibrant lawn takes commitment, but the rewards of a successful grass seed project are worth the time and resources you invest. A beautiful lawn can improve your home’s value, benefit the environment and enhance your family’s quality of life. Even if you’re a first-time lawn grower, you can seed right and avoid these common mistakes:
1. Planting the wrong type of seed
Choosing appropriate grass varieties is the first step in ensuring your lawn performs up to your aspirations. Grasses vary widely in their preferences and tolerances, just like other types of plants. Kentucky bluegrass and Bermudagrass, for example, differ significantly in climate and maintenance requirements. Planting grass varieties appropriate to your growing region gives your seed a natural advantage.
Even with similar seed types, all grass seed isn’t equal. Learn what’s actually inside the seed bags you or your lawn professional buy. By understanding the seed tags on grass seed products, you can be sure you invest in quality seed. Cheaper price tags can mean less seed versus fillers, old seeds past their prime, more weed seeds and lower germination rates. Getting seed right from the start benefits your lawn and budget.
2. Skipping the soil test and recommendations
Seeding success depends on an environment conducive to good grass growth. Knowing how your soil measures up on certain essentials, such as soil pH and plant nutrients, allows you to provide the foundation an outstanding lawn needs. Soil testing processed through a reputable soil laboratory eliminates guesswork and reveals changes you need to make.
Without knowing where your soil stands, well-intended soil amendments and fertilizers can harm grass instead of help — or simply go to waste. Incorporating your specific soil lab recommendations helps circumvent potential problems and unnecessary setbacks. That’s one reason turf professionals emphasize regular soil testing to start seed right and keep lawns healthy and vibrant. Your local county extension office can help with testing kits and lab referrals.
3. Using lime incorrectly or unnecessarily
Many homeowners think lime is a lawn care necessity, but that doesn’t hold true across the board. Normal lawn care can naturally cause soil pH to drop lower over time, and lime applications benefit lawns that need pH raised. But in some cases, soil pH may already be high. Using too much lime or applying it unnecessarily can be as damaging as failing to add lime when it’s needed.
When soil test results show your lawn’s soil pH is below levels needed for optimal grass health, liming in accordance with recommendations restores proper pH balance, increases nutrient availability and helps keep lawns green. While many lime products are slow to work, products such as Pennington Fast Acting Lime speed up the process and start working immediately.
4. Ignoring recommended seeding rates
Using the proper amount of seed for your project influences success, whether you’re starting from scratch or overseeding an existing lawn. New lawns or spot repairs take about twice the amount of seed needed for overseeding thin areas. Quality grass seed labels include guidance on optimal seeding rates to maximize your results.
Don’t overdo or cut corners. Too much grass seed causes undue competition for resources such as light, water and nutrients, and grass seedlings struggle as a result. Too little seed leaves lawns thin or bare. Always follow “best practice” guidelines for planting grass seed, including site preparation and good seed-to-soil contact, and stick with recommended seeding rates for lush results.
5. Miscalculating your lawn dimensions
Getting your seeding rates right requires knowing the correct size of the area you need to cover. One of the most common problems grass professionals see is when homeowners misjudge their actual lawn areas and over-apply grass seed or other products, such as fertilizers and herbicides.
Knowing your total property size is just the start. All non-lawn areas must then be deducted. This includes the footprints of your house, garage and outbuildings, as well as walkways and the driveway. Only then can you calculate your actual lawn area and the amount of seed you need. Time spent on proper measurements prevents wasted product, wasted money and poor results. Get it right and every bit of seed and labor work in your favor.
6. Planting without regard for proper timing
It can be tempting to plant seed as soon as the need arises. But proper timing has an important impact on results. Grass growth occurs in seasonal cycles, which vary according to the grass types common to different regions. Timing your seed projects to coincide with growing cycles greatly improves your rate of success.
For most of the country, fall is the best time to plant grass seed. This is when cool-season grasses such as Kentucky bluegrass and tall fescues peak in growth, and conditions enhance fast germination and establishment. When paired with innovations such as water-conserving Pennington Smart Seed, proper timing leads to other advantages, including less input of resources, less maintenance and better results.
7. Using weed treatments or weed & feed fertilizers with seed
One of the ways weed treatments work is by preventing germinating seeds from establishing roots. But these products, known as pre-emergents, can’t distinguish between harmful weed seeds and desirable grass seed you put down. Using these products too close to newly planted seed — in timing or proximity — stops grass seed in its tracks, along with the weeds. Post-emergent weed treatments aimed at existing broadleaf weeds can also injure immature grass seedlings.
Always read and follow herbicide and fertilizer labels, especially the instructions for use on newly seeded lawns and your grass type. As a general rule, avoid pre-emergent weed treatments at least 10 to 12 weeks before seeding — or longer for some products. After planting, reserve broad-spectrum weed treatments until new lawns have been mowed at least two to three times; for fall-planted seed, that usually means spring.
When it comes to your lawn aspirations, you can bypass common grass seed mistakes and head straight for success. Make the most of your investment of time, money and grass seed, and enjoy the exceptional results. Pennington is committed to helping you grow the finest lawn possible and enjoy all the benefits that a beautiful, healthy lawn holds.
Pennington and Smart Seed are trademarks of Pennington Seed, Inc.
Lawn myth busting: Skip spring ‘weed and feed’
Editors note: Rossi is a turf specialist and associate professor in the Department of Horticulture, Cornell University. This is the first in a series where Rossi debunks common lawn myths. His advice targets cool-season grass growing regions in the Northeast, but may be applicable in regions with similar growing conditions.
ITHACA, N.Y. – It’s a sure sign of spring: The robins return and millions of lawn owners head out to apply fertilizer and weed- killers to their lawns – a rite widely known as “weed and feed.”
But here’s the problem: Early spring probably isn’t the best time for you to fertilize your grass or apply herbicides unless you have a history of weed problems.
Let’s start with the herbicides. Weed and feed products designed for early-spring application usually contain pre-emergent herbicides. They work by preventing weed seeds from sprouting, and they can be an effective way to control crabgrass and some broadleaf weeds.
Trouble is, this assumes that you’ve got weed seeds in your soil ready to sprout. If you’ve been using pre-emergent herbicides regularly or otherwise doing a good job of controlling weeds and keeping them from going to seed, you may have exhausted the supply of weed seeds in the soil. If that’s the case, applying pre-emergent herbicides is like clapping your hands to keep the lions away.
Then there’s the fertilizer. It should be mostly nitrogen, and I’ll admit that it can really green up the grass in a hurry. But it can also fuel lush top growth at the expense of roots, and you want those roots going deep for moisture so the grass can outcompete weeds during the hot, dry summer months to come. That lush top growth also means you’ll need to mow more often and deal with more clippings.
If you’re going to apply fertilizer, Memorial Day and Labor Day are better times to do it. And with recent restrictions on phosphorus fertilizer in many areas and the lack of evidence that potassium will improve your lawn in most circumstances, shop around for fertilizers that are all nitrogen.
Other weed and feed products are designed for late-spring application. They contain herbicides designed to kill actively growing broadleaf weeds like dandelions. But if you want to kill broadleaf weeds, these herbicides are much more effective if you apply them in fall. At that time, the weeds are storing up reserves for winter and moving nutrients from the leaves to the roots. They move the herbicide to the roots at the same time, resulting in a better kill.
And unless your weeds are running rampant, try spot spraying them in the fall instead of putting down herbicide over your entire lawn. That’s just one small step you can take for sustainability.
If weed and feed has become a ritual for you, it’s time to break the habit. Try skipping it this year and applying fertilizer and herbicide only if you need them and in separate treatments at the times when they will be most effective.
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.
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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.