Thicken Your Lawn: It’s Time For Overseeding!


Overseeding, sometimes called reseeding, is the process of distributing grass seed over an existing lawn. According to information provided by Pennington Seed, there are two primary reasons for seeding existing turf in this manner. First, to either rejuvenate a patchy or thinning lawn or to prevent one. Many grass types will thin out as part of their natural maturing process. Your turf may also develop thinning or bare spots due to the stresses of heavy traffic as well as certain diseases or pests. Simply put, if your lawn is receding, consider reseeding.

Purpose of Overseeding a Lawn

Lawn care professionals will frequently use overseeding as a preventative measure. Instead of waiting for the thin areas or bare spots to appear, they will reseed the lawn so that the new grass plants appear before the weak areas are able to develop. Rather than fixing a poor-looking lawn, this proactive approach keeps the turf looking full, green, and healthy.

The second reason for overseeding is to bring up color when warm season grasses go dormant in winter. This is done by seeding the warm season lawn with a cool season grass seed mix that will produce color during those months when the warm season grasses are dormant. It may seem odd to plant cool season grass seed on a warm season lawn but the very conditions that cause the warm season grass to go dormant—milder daytime conditions and cooler nighttime temperatures—will allow the cool season grass to thrive, if only temporarily. The desired result is year-round green color.

How and When to Reseed

So far we’ve looked at what overseeding is and why to do it. Now let’s address when and how. Cool season grasses of the northern regions enter a period of vigorous growth during late summer and early fall. The soil is still warm enough for the seed to germinate and the cooler temperatures, along with moist conditions, stimulate growth. This is the best time to overseed a northern lawn, with spring being the second best.

By comparison, warm season grasses experience their active growth beginning in late spring, which makes that the better time to overseed a thinning lawn or to prevent one. If winter color in a southern lawn is the goal, fall is the time—just as the existing warm season grass is beginning to turn brown and go dormant.

Without proper preparation and execution, one can spend a great deal of money on overseeding and not see great results. In order for grass seed to become grass plants, it must have an opportunity to germinate and thrive. Simply distributing seed, even good seed, over a lawn may not be good enough, especially if the soil is compacted, there is an excessive thatch layer, or both.

Improve Your Lawn With Core Aeration

Grass seed that cannot get into the soil and receive the necessary moisture and nutrients has a good chance of becoming bird food. Spring-Green’s core aeration service disrupts the surface of the lawn and the soil beneath it by extracting plugs of soil and plant material and then depositing them on the lawn’s surface. This process helps loosen compacted soil and break down thatch, allowing water, nutrients and grass seed to penetrate the soil. For this reason, we recommend scheduling core aeration and overseeding in combination.

Proper seed selection is also important. Use a quality seed mix that is well-matched to your growth region as well as to your overseeding objective. One objective may be to thicken an existing lawn without substantially altering the grass type. Another is to augment the turf by introducing additional grass types to it, such as the introduction of cool season grass seed to a warm season lawn in order to enhance winter color.

Watering, feeding, and weed control practices during the weeks following core aeration and overseeding may also vary according to the specific needs of your lawn. Contact your neighborhood lawn care professional at Spring-Green to obtain more information, ask questions, or schedule this service.

DIY Core Aeration – Is Aerating Your Lawn Worth It?

core aeration

Of all the beneficial things you could do to ensure a healthy, beautiful lawn, core aeration is second only to fertilization. By disrupting the surface of the lawn and the soil beneath it, core aeration allows more air, water, and nutrients to reach the turf’s root zone. This in turn encourages better lawn root development below the surface and—you guessed it—healthier, thicker, greener plant growth above. Compacted soils are loosened, restrictive layers of surface-level thatch are broken, and your turf uses these improvements to its natural advantage, growing stronger and healthier as the surface repairs itself.

Virtually all U.S. regions and all common turfgrasses can benefit from regular aeration. What differs somewhat is the timing. According to information provided by Bayer Advanced, the best time to aerate a lawn is prior to a period of vigorous growth, during which the lawn can best recover from the disruption intentionally created by the aeration process. For cool season grasses, that time is late summer into early fall, making sure to allow at least a month of growing time before the threat of frost sets in. For warm season grassses, late spring to early summer is your best bet.

DIY (Do It Yourself) Core Aeration

Is core aeration worth it for your lawn? Yes, absolutely! Is it worth doing it yourself? Let’s weigh the options of do-it-yourself (DIY) aeration versus having the work done by a professional lawn care service.

No matter who does it, the work is performed using a specialized core aeration machine. This is a powerful and somewhat heavy motorized device that drives hollow tines several inches into the ground, extracts plugs of soil and plant material, and then deposits them on the surface as it moves forward. The desired result is a visible pattern of holes in the ground and plugs laying on the turf. Over time, the holes will be filled in with loosened soil, new roots, and grass plants, while the plugs break down and assist in the decomposition of the thatch layer that builds up on the soil surface.

This would be a piece of cake if the machine did all the work and the operator merely had to throw a switch on or off, but such is not the case. The machine operator controls where the machine goes, taking special care to avoid damage to irrigation heads, pavement features, flower beds, children’s toys, and other common obstacles. The operator must also determine whether soil conditions are favorable before commencing the operation. The key concern here is moisture. Soggy soil will clog the tines whereas overly dry soil will be difficult at best to penetrate. Aerating during a prolonged period of drought or excessive heat may do more harm than good.

The application of additional grass seed to an existing lawn, sometimes called overseeding or reseeding, is best done immediately following core aeration of a lawn. Fertilizer applications are also more effective at this time. This is because the openings caused by the aeration process make it easier for the new seed and/or nutrients to penetrate the soil. Obviously the individual applying these materials must know what to apply and at what rate.

Better To Do It Yourself or Hire a Professional?

So which provides the better value for core aeration, DIY or using a professional lawn care service? Consider the following.

● Who will transport the core aeration machine to and from your property?
● Who will determine whether conditions are favorable to aerate your lawn?
● Who will ensure the safe and effective operation of the core aeration machine?
● Who will be responsible for any damage incurred to properly identified obstacles?
● If applicable. who will be responsible for properly overseeding/reseeding your lawn?
● If applicable. who will be responsible for properly fertilizing the lawn after aeration is completed?

When properly performed, under favorable conditions and at the appropriate time, core aeration will most assuredly benefit your lawn, whether you do it yourself or bring in a lawn care professional. With that said, if you have questions or concerns about core aeration or any aspect of caring for your lawn, please do not hesitate to contact your neighborhood lawn care professional at Spring-Green. We have a wealth of professional lawn care experience to share with you.

Rejuvenate Your Lawn with Core Aeration and Reseeding

core aeration and reseeding

For cool-season turfgrass, fall is a time of renewal and recovery from the stresses of summer heat. As the temperatures start to moderate and rainfall increases, the turf plants will start growing new roots and new plants to replace those that were damaged or even killed during the summer. Spring may be the time when other landscape plants start to grow, but fall is the time of regrowth for cool-season turfgrasses with core aeration.

Cool season turfgrasses like Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue have varying degrees of tolerance to heat and drought:


Heat ToleranceDrought Tolerance
Fine FescueGoodVery Good
Kentucky BluegrassGood to PoorGood
Perennial RyegrassGoodGood
Tall FescueVery GoodVery Good


These ratings are based on an average summer.  If conditions are extreme, the turf will suffer.  For example, roots of Kentucky bluegrass will start to die when soil temperature in the top inch of soil will start to die. All these grasses can survive about 28 days without water, but they all will thin out if a drought lasts much longer than 28 days.

Fall Core Aeration

One constant in lawn care is that all lawns will benefit from an annual core aeration. Core aeration is performed by a machine that travels across the lawn and has a series of tines built in that puncture the soil and remove 2 to 3-inch-long plugs or cores of soil and thatch and deposits the them back on the lawn’s surface. This process will open the lawn to provide more air, water and nutrients into the turf root zone. Strengthening the roots is key to having a healthy lawn.

The best time to do core aeration on a a cool-season lawn is in the fall, from mid-August through mid-December. A lawn can also go through aeration in the spring, but the optimum time is in the fall. The roots of cool season turf grow best when soil temperatures are in the range of 60 to 80 degrees. Even if the lawn is aerated before the soil temperatures drop to these favorable levels, the aerification process will be completed to help promote better root growth when the temperatures drop.

Fall Lawn Reseeding

A great time for lawn reseeding is shortly after it has been core has gone through aeration. Grass seed needs to come in contact with soil and receive adequate moisture to remain viable once the germination process begins. A good portion of the seed will end up in the core holes, which ends up being a great place for the seed to germinate. The soil in the core holes will be cooler and remain moist and the seed will have a much better chance of germinating. Soil temperatures for seed germination for the different cool season grasses are:


Kentucky Bluegrass59 to 86°
Fine Fescue59 to 77°
Perennial Ryegrass68 to 86°
Tall Fescue68 to 86°


Even if your area did not have to endure any extreme heat or drought this past summer, having the lawn aerated and reseeded will help ensure an even better lawn next year. One other important part of a fall lawn overseeding program, it needs to be completed early enough for the seed to germinate and sufficiently grow before inclement weather sets in for the winter. In the colder parts of the cool-season areas, try to have the seeding completed by the end of September. If you are in the more southern part of the cool season areas, you have more time, but you should try to have it completed by end of October.

If you are interested in having your lawn core aerated and overseeded this fall, contact your neighborhood lawn care professional at Spring-Green and make arrangements to rejuvenate your lawn this fall.

Be Nice to Your Lawn and Have it Core Aerated

Lawns around our houses, businesses, churches, hospitals or lawns that are used for sporting events, playgrounds or parks are not natural systems. Therefore, they need to be maintained in order to grow and stay healthy. Lawns that are not properly maintained are thin and usually full of weeds (not just dandelions). By caring for your lawn and ensuring it is growing well, you are making a big difference environmentally such as:

  • Reducing pollution
  • Preventing floods
  • Providing oxygen

Your lawn is a GREAT thing.

The turfgrass varieties planted for lawns are great, but they are susceptible to more stresses than in their natural environment. Most of these turfgrasses are not native to North America, but were brought here from Europe, Africa or Asia. The soil preparation for the new grass, whether it is sod, seed or springs, is usually not that good. These grasses are expected to perform not under the best growing conditions. That is why they need fertilizer, pest control products and other mechanical processes to help them adapt to their environment.

One of the best things that can help any lawn is to core aerate it by using a machine called a core aerator. Nowadays, there are many styles of core aerators including walk-behind models, ones that are pulled by a small tractor and there are even ones that are a stand-on type. Most homeowners have their lawn care or maintenance company perform this work, but many hardware or rental stores carry small walk-behind models as well. Core aerators weigh several hundred pounds and a pick-up truck is the best way to transport them.

When a core aeration machine travels across a lawn, it removes small cores or plugs of soil and deposits them back on top of the ground. This opens up the lawn for more air, water and nutrients to penetrate into the root zone and allows for better root growth. Having a good root system is important for growing a healthy turf.  core aerated lawn

Besides providing better root growth, core aeration helps reduce thatch levels as well. Thatch is a layer of roots, rhizomes and other organic material that builds up at the soil line.  Thatch acts like a sponge and absorbs much of the water and nutrients applied to a lawn, which is where many of the roots will grow. A sponge will quickly dry out in the sun and so will a thatch layer. It is also a home for insects, diseases and weed seeds. Core aeration will help to mitigate these problems. The cores that remain on top of the lawn will slowly break down through normal mowing and watering. The microorganisms in the soil will intermingle with the thatch and begin to decompose it naturally. Thatch can take years to build up to detrimental levels, so one aeration will not be enough. It may be necessary to aerate twice a year – spring and fall.

The best time to core aerate a lawn is when the roots are actively growing. For warm-season grasses, the roots are most active after the lawn comes out of dormancy in the spring. Therefore, aerate in April through June. For cool-season grasses, the most root growth occurs in the fall so therefore the fall is an optimum time to aerate. Roots are active in the spring as well, so aerating in the spring can also be completed. A lawn can be aerated at any time of the year as long it is moist enough to allow the tines to enter the soil, however the lawn may not benefit as much if it is aerated when the roots are active.

Cool-season turfgrasses can benefit from annual overseeding. The best time to do this is in the late summer to early fall. Core aeration prior to overseeding provides a place for the seed to be in contact with the soil and allows for better germination. Just about every cool season turfgrass lawn will benefit from an annual overseeding.

Besides fertilizing, one of the best things you can do for your lawn is to core aerate it. It is the only process that physically changes the structure of your lawn. Be kind to your lawn and have it aerated.

Have questions about the maintenance for your lawn or want to get started with core aeration and oeverseeding for your lawn? Contact your neighborhood Spring-Green for more information.

Should You Overseed Your Lawn This Spring?


A common question we receive in the spring is in regards to overseeding your lawn.  If you live in an area with warm season grasses, like Centipede or Bermuda grass, reseeding is not a very common practice and it does not work all that well. For those who live in areas where cool-season grasses like bluegrass or turf-type tall fescue grow, seeding can be a successful and a necessary part of caring for your lawn.

The best time to overseed an existing lawn is late summer until early fall. If you did not have a chance to do so last year, it might be something you want to take care of this spring.

You can overseed in the spring, but here are 4 important aspects that you should consider:

  1. Be conscious of the season for crabgrass preventers – If you seed in spring, you cannot apply most standard crabgrass preventers. These materials keep crabgrass seeds from germinating, as well as the new seeds. In the past if crabgrass has been a problem in your lawn, it would be advisable to wait until the fall to start overseeding. For most crabgrass materials, there is a 16 week waiting period between seeding and applying a crabgrass preventer.
  2. Be conscious of the season for broadleaf weed controlBroadleaf weed control is the same as crabgrass preventers, except the waiting time is less. If a broadleaf weed control is applied to an area, the standard wait time before seeding is 3 to 4 weeks. Once the new grass has germinated and become established, it has to be mowed two or three times before any weeds can be sprayed.
  3. Aerate before broadcasting seed – One of the best methods to ensue good germination is to aerate the lawn first before broadcasting seed across the area. Broadcasting seed across an established lawn will result in little to no germination.
  4. Water, water, water – Finally water is critical to the success of seeding at any time of the year. Once the seed germinates, the roots are tiny and have an immediate need for water.  If the roots dry out, the seed will die. Be sure you have some way to provide adequate water once the seed has been broadcast across the area. The best method is to have an automatic sprinkler system. If the system has not been started for the year when you complete the seeding, you may have to manually water the areas until your system is turned on. Depending on the variety of seed, you may need to keep the area moist for 4 to 6 weeks after seeding.

As you can see, seeding in the spring is not the easiest thing to do, especially when dealing with weeds. It is often better to keep the weeds down throughout the summer and then complete the seeding in the fall.  If you are a Spring-Green customer, contact your local Spring-Green and they will advise you with the best information on helping your lawn looks its best.

Resuscitating a Dead Lawn with Core Aeration and Overseeding

Benefits of Core Aeration and Overseeding to your lawn

Harold Enger, Spring-Green’s Director of Education, received a question from a homeowner about fixing his dead lawn. After hearing about the problem, he recommended core aeration and overseeding to help revive the lawn.

“My lawn is brown with few things growing (even weeds). I believe it’s the result of rock hard soil. Last year a small patch of lawn was ripped up (gas line installation) and that patch now has green, healthy grass. I thought about tilling my entire lawn but its costly ($2k). I have aerated in the past but that has done nothing. But what if I were to aerate it A LOT at once (4-5 times) while throwing top soil down in the midst of aerating?”

Thank you for submitting you question. Your idea of core aerating several times is an excellent one. I suggest you core aerate in opposing directions, but the more holes you make, the better it will be for your yard. You also want to wait until the soil is moist so that the tines of the aerator can penetrate the ground to a decent depth of 2 to 3 inches. Either thoroughly water your yard or wait until it your area receives about ½ inch of rain.

Here are a couple of additional recommendations:

  1. Take a sample of your soil to either your county extension service or to a John Deere Landscapes retail store for a soil analysis. The results can take two weeks to get back, but that should not delay any of the other work that needs to be completed. The soil test will help you to determine the pH and nutrient requirements of the soil in your yard.
  2. Spreading top soil is a good idea, but I suggest you use humus compost to help improve the soil even more.
  3. After aerating and top dressing, I suggest you overseed your lawn with Turf-Type Tall Fescue. Together, core aeration and overseeding help combat lawn diseases and stresses and thicken the lawn with new grass plants ready to take hold in previously bare areas. After deciding on core aeration and overseeding, many people opt for purchasing cheap seed, but the results are usually poor. Again, a John Deere Landscape Store is a good place to purchase seed. You should use about 4 to 5 pounds of seed per 1,000 sq. ft. To find a John Deere Landscapes store near you, go to their website,, click on “Our Locations” and enter your zip code. I did so and found many stores near Huntington. The closest one appears to be in Bethpage.
  4. Even though you have core aerated and overseeded your lawn, you may have to live with some weeds this fall. Broadleaf weed control cannot be applied until the new grass has germinated and mowed two or three times.
  5. After you have finished with your core aeration and overseeding, the most important recommendation is to make sure to water the newly seeded area for at least three weeks. It does not need a lot of water, but the areas should be kept moist for at least two weeks.

I hope these recommendations help. Feel free to contact me if you have any additional questions. Or, if you need professional assistance bringing your lawn back from the dead, get in touch with your local Spring-Green for core aeration, overseeding, fertilization, weed control, and more.

The Best Time to Aerate Your Lawn, for Cool and Warm Season Grasses

core aerator used by a Spring-Green technician

September is here and the amount of sunlight is becoming less and less each day. Less sunlight means that the leaves on trees will start to show their fall colors, summer weeds will begin to slow down growing and another summer is coming to a close. Early fall lawn projects are on homeowners’ minds, and many are wondering if this is the best time to aerate their lawns.

Aerating Your Lawn in the Fall Works for Cool Season Grasses

For cool-season grasses, this is the time of year when the top growth slows down and the root growth increases. Fall is the time when these grasses naturally “repair” the damage that was caused by the stresses of summer. Heat and a lack of rain have taken their toll on cool-season lawns. Insect and disease outbreaks add to the damage level and have left many lawns in a sorry shape for the fall.

In my 37+ years in lawn care, I have always been amazed at the recuperative ability of turfgrasses to recover from these stresses. Even though they can come back, one of the most important things you can do to help a cool-season lawn recover is to core aerate to increase rooting and the overall health of the lawn. It is also a good idea to overseed the lawn to help it fill in even faster. By opening up the lawn, more air, water and nutrients can easily reach the root zone. The cores or plugs of soil that are left behind will breakdown and incorporate into the thatch layer. It is the microorganisms in the soil that feed and the thatch to lessen its impact on the lawn.


When Is the Best Time to Aerate Warm Season Grasses?

For those of you that have warm-season grasses, the best time to aerate your lawn is in early summer. If you aerate the lawns right now, they won’t be harmed, but the benefits are much less.

When Is the Best Time to Add Nitrogen Fertilizer?

If you plan to apply an application of nitrogen to your warm-season lawn one more time this year, be sure to do so by the end of September. Stimulating new growth in October or November can be detrimental to the lawn if an early frost hits the area. Too much nitrogen in the fall can also lead to an increase in disease activity the following spring.

Before we know it, leaves are going to begin to fall. There are a number of fall lawn and landscape projects that are coming up as the year moves on. I will be discussing those in future blog posts. Enjoy the last of the summer warmth while you can.

Core aeration is just one of the services Spring-Green offers to help homeowners prepare their lawns for winter. Contact your local Spring-Green for a free estimate of your lawn’s unique needs.

Overseeding in the Fall: Tips on Watering and Raking

Leaves Covering a Backyard

The following question came in on Spring-Green’s YouTube page; one of our viewers was concerned about how to best rake leaves after overseeding in the fall. To give your new seedlings the best chance possible, follow the tips below.

“Hi Spring-Green! I just aerated and overseeded my lawn 1 week ago with tall fescue. I am having lots of leaves falling onto my lawn now. My question is should I rake them all up periodically? I am concerned that I will damage the new seedlings while raking, but also concerned that germination will be decreased with the leaves shading sunlight from my seed.”

“Thank you for your great question +jshelt22! Now that you have overseeded in the fall, you will want to do something with the leaves depending on the type of leaves and the amount that have fallen. If the leaves are large and not too numerous, you can use a leaf blower to move them to the side. Keep the blower low and blow them somewhat parallel to the ground, if possible. Try not to blow at a steep angle. If the leaves are not too numerous, dry and smaller in size, like a willow oak, crabapple, Bradford pear or locust, use your mower to mulch them. Set your mower at a higher setting before going across the lawn. The mulched leaves will help to prevent the soil from drying out too quickly. Your mower will not suck up the seed as it does not have that much sucking action—not like a vacuum cleaner. The wheels may bend over the new seedlings, but they should recover. Most of the seed will germinate within the core aeration holes, so it should be less of a concern. The most important aspect of overseeding (whether you do it in the fall or earlier in the season) is providing enough water to prevent the seed from drying out. This may mean daily watering for three to four weeks after seeding. Good luck and let us know if you have any other questions!”

Spring-Green can help with core aeration and overseeding. Talk to your local franchise owner to learn more about the benefits of these services!

The Basics of Lawn Care: Aerating, Overseeding, and Fertilizing

On Page Seeding

Like many people across the country, Mr. Roy wondered how to reclaim his thin, bare lawn after an especially harsh winter, so he sought the advice of Spring-Green’s authority on lawn care, Harold Enger. Read below to see how you, too, can thicken up your grass and get your lawn back.


“My lawn is very thin and has some bare spots after this hard winter. What do I do to thicken up my lawn and fill in the bare spots?”

Mr. Roy, thank you for sending in your question. I would not be doing my job if I didn’t tell you that you should contact Spring-Green and request a lawn evaluation. You can visit our website at or call (815) 436-8350. If you prefer to attempt to do the work yourself, here’s what I suggest:

Step 1: Core Aerate

Rent a core aeration machine from your local hardware store or rental center. This machine travels across the lawn, removing plugs of soil and thatch and leaving them on the lawn. This opens up the lawn to allow more air, water and nutrients to penetrate the soil, and it also helps to build the root system. The cores or plugs that are left will dissolve back into the lawn with rain or normal irrigation.

Step 2: Plant Grass Seed

Following core aeration, you’ll have a good site for seed germination. I usually recommend seeding cool season grasses in late August to early September, but if your lawn is thin, then you may want to consider seeding this spring. There are a few considerations that you have to keep in mind. First, you cannot apply a crabgrass preventer as this product will keep your grass seed from germinating as well. Second, you cannot apply a broadleaf weed control for dandelions, clover or other broadleaf weeds until the new seed has germinated and has been mowed three or four times. Light, frequent watering is the best for new seed. If you plan to seed your entire lawn, you may be disappointed with the results if it cannot be watered. I recommend a blend of 70% Perennial Ryegrass to 30% Bluegrass. Most hardware stores carry seed, and this is one area where you don’t want to look for the cheapest price. Buy good, quality seed.

Step 3: Fertilize Your Lawn

Applying fertilizer will help thicken up the lawn by stimulating new growth. As with grass seed, get a good quality fertilizer. Although there are regulations in Illinois that prohibit the use of fertilizer that contains phosphorus (the middle number on the fertilizer analysis) you are allowed to use it after seeding. If possible, use a fertilizer with an analysis of 14-14-14. Read the label that comes with the bag to ensure you are not over-applying the product.


In addition to following the above order, you want to follow good cultural practices, too. Mow at 2.5 – 3 inches in length, leave the clippings on the lawn after mowing and do your best to supply 1 inch of water to your lawn at least once every other week. In my experience, I usually try to talk customers out of seeding in the spring so that the weeds can be kept in check throughout the spring and summer, then, it makes sense to aerate and overseed in the fall. The fertilizer you apply now and throughout the summer will help to thicken the lawn and get it in better shape for the fall. Or, as I said earlier, contact Spring-Green and let us do the work for you!