How Long After Seeding Can You Weed And Feed

Is your turf looking a little dull, thin or patchy? Revitalize your grass by aerating and overseeding, or creating holes in your soil to plant fresh … The practice of overseeding lawns is essential for maintaining your lawn’s long-term health and vibrancy. Yet it still remains one of the most overlooked disciplines by homeowners. Lawn overseeding gives your lawn thicker growth, better color, and greater resistance to disease and drought! Learn how to overseed with Ryan® turf equipment.

7 Aeration and Overseeding Mistakes You Should Avoid

To revitalize your grass, you may consider aerating and overseeding, or creating holes in your soil to plant fresh seedlings. In fact, when done correctly, aerating and overseeding can be extremely beneficial to the wellbeing of your turf. Unfortunately, mistakes can be all too easy to make— and could cost time and money, with little return.

Be sure to avoid these seven aeration and overseeding mistakes to get the thick, healthy look you desire:

1. You don’t choose the right equipment.

We’ve all seen the do-it-yourselfers walking across their lawn in cleats, poking holes in the soil. Instead of investing in an aeration machine, they think aerating is just about creating holes— but actually, the concentrated force of stepping with a spiked shoe further compacts your soil. Even spike aerators, which use a solid tine or fork to poke holes, can cause additional compaction in the areas around the holes.

For best results, use a plug aerator, which removes a core, or plug, of grass and soil from your lawn. Look for an aerating tool or machine that removes soil plugs approximately two to three inches deep and roughly half to three quarters of an inch in diameter, about two to three inches apart.

2. You don’t know how to use your aeration machine and accidentally damage your turf.

After you choose the right aeration equipment, much of the success of your new growth will be the result of how well you operate the aerator. Walk-behind aerators are a common choice but can be heavy to push. Large lawns can mean achy arms and sloppy navigating, resulting in inconsistent growth.

In addition, during each turn, you must disengage the tines by lifting up from the handle to prevent damaging the turf. This can be time-consuming, so instead, some operators will lift and spin the whole unit when it’s time to turn, potentially causing compaction and bare spots later on. Make sure you choose the right machine and understand how to use it to ensure the best results for your lawn.

3. You aerate and overseed during the wrong time of the year.

The proper time to aerate is when new life has the greatest chance to grow in your region. You wouldn’t want to aerate and overseed too early, before the last frost hits for example, and kill the seeds. You also wouldn’t want to do it during the peak of a hot summer, when the harsh sun and temperature suppress new growth.

For cool-season grasses, common in northern lawns, aerate early fall or spring. Warm-season grasses, common to southern lawns, grow best in the late spring or very early summer. Not sure which applies to you? Here in Pennsylvania, cool air and moist soil in the fall and spring make it the perfect time to lay fresh turf, helping to build greater resistance against disease, insects, and drought.

4. You aerate and overseed during dry conditions.

Aerating is easy on your turf, and you, when your soil is slightly moist. Overly dry and compact soil is harder to penetrate and requires more manual effort to push the machinery. Especially during times of drought when you grass is already stressed, it’s best to wait until the day after a good rainfall before aerating.

5. You don’t keep your lawn moist after aerating and overseeding.

After planting the seeds, you must make sure they’re covered with moist soil— at least a fourth of an inch— to foster growth. A common mistake rookie aerators and overseeders make is thinking that the natural rain cycle will provide all the water you need, but a few days without moisture could mean bad news for a new seed.

For about three weeks after seeding, or until the grass begins to peek out of the dirt, set a daily watering schedule. Once the grass has gained a little height, you can ease back to your normal pattern.

6. You mow too soon.

After you lay down your seedlings, they’ll need time and the right environmental protection to grow. They’ll need to acclimate and set roots before the first mow, so during the first two to four weeks post aerating and overseeding, don’t mow. This time varies depending on your area and the type of grass you planted; for example, fescue and ryegrass typically take about 10 to 14 days to germinate, while Kentucky bluegrass might take up to four weeks. A lawn care professional can advise you on the right timespan.

During this sensitive time of growth, try to allow avoid heavy foot traffic on your property, which could compact the seeds too deeply. Once the grass reaches about three to three and half inches, you can fire up the mower for a fresh cut.

7. You fight weeds too early.

Weed control can work wonders keeping invasive growth at bay on a healthy turf, but chemicals and herbicides can harm seeding’s roots and fresh blades. Even organic and natural solutions can cause stress on the young plants, so it’s often best to wait until your grass is strong before laying down any weed control substances. We advise waiting until you’ve mowed your new grass four to five times before tackling any emerging weeds.

Sometimes, It’s Better to Trust a Professional

Being mindful of these seven aeration and overseeding mistakes can certainly help create the beautiful turf you long for, but landscape maintenance can be time-consuming— and there’s a lot of dos and don’ts along the way!

A lawn care professional will know the right equipment and understand the needs of your unique property. Our team at Caramanico is here to get the job done right and prepare your turf for vibrant growth for your commercial property. Give us a call at 610.499.1640 or fill out this form to get a free property assessment today.

​Properties We Serve: Businesses, Colleges & Universities, High Schools & Elementary Schools, Shopping Centers, Apartments & Condominiums, Retirement Communities, Golf Courses & Country Clubs, Medical Centers, and more!

Service areas: Chester County, Pennsylvania; Delaware County, Pennsylvania; Montgomery County, Pennsylvania; Philadelphia County, Pennsylvania; Bucks County, Pennsylvania; Hunterdon County, New Jersey; Somerset County, New Jersey; Mercer County, New Jersey; Camden County, New Jersey; Gloucester County, New Jersey; New Castle County, Delaware

Tips and Techniques for Overseeding Lawns

The concept of overseeding lawns as part of a regular maintenance has been around for years, but it is still new to many homeowners. This one step will do more to improve the quality of your lawn than almost anything else you can do.

For the organic and conventional home turf experts, this is one of the best things you can do. Years of experience proves this. The information on this page will explain why overseeding your lawn is so important for a thick, healthy, and weed free lawn.

The two images below show the same fescue lawn before and after seeding. Overseeding was performed in early fall and was recommended due to thinning grass and increasing weed problems. The second image was taken the following spring after overseeding. The grass is thicker and the thin areas have filled in.

Grasses that Benefit From Overseeding

The practice of overseeding lawns is really nothing more than spreading grass seed over an existing lawn. The golf industry has been doing it since the sport began and is an important step in maintaining quality turf. Knowing how to do it correctly is the key. There is no need to invest in expensive equipment, just what is needed to do it correctly.

Not every grass type requires overseeding. The practice of overseeding lawns is primarily reserved for cool season bunch type grasses such as tall fescue, fine fescue, perennial and annual ryegrass and occasionally bluegrass. There are exceptions, but for most home lawns, grass types that spread by the production of “runners” are not generally overseeded unless it is damaged or diseased. This includes most warm season grass varieties. An exception is bermudagrass that is occasionally overseeded in the fall using a cool season variety.


Understanding Grass Growth

Most cool season grasses are bunch type grasses. As the name sounds, they grow in a bunch, but growth habits are largely misunderstood. When lawn grass seed germinates, a single grass blade emerges. The grass crown, at the plant’s center, have roots growing down from the crown and the blades growing up. Grass plants expand as new grass blades, called tillers, develop and grow along side the original crown. Hundreds of new tillers can develop, each having its own crown, roots and blades. A blade of grass has a short lifespan of about 6 weeks and must continually produce new tillers or the grass thins out. If you would like a better understanding of how grasses grow, see the page on Photosynthesis.

Why is Overseeding lawns Necessary?

After several years, mature plants begin to slow down their reproduction rate. Since a blade of grass lives only an average of 45 to 60 days, production of new tillers must continually outpace the dieback of older leaves. Young grass will produce tillers faster than older grass. Therefore, one of the most important secrets to maintaining a healthy, thick lawn is to make sure your grass is young. (Nick Christians, PhD, Iowa State University) The practice of overseeding lawns is the easiest way of Keeping grass young.

When is the Right Time for Overseeding Lawns

Overseeding lawns consisting of Cool season grasses should be done in late summer or early fall. There are many reasons for this. With fall germination, the young grass will have two or three months to become better established before temperatures drop too low and growth stops. Next spring, the young plants will have another few months to develop deeper roots before the summer heat sets in. This is the primary reason, but there are also other reasons for overseeding lawns in the fall. Below are a few:

  • Overseeding lawns in fall reduces or eliminates competition from summer weedy grasses, such as crabgrass, foxtails, and other weeds.
  • Soil temperatures are still warm in the fall, which is necessary for seed germination, while the cooler air temperatures are better for grass growth.
  • Rain amounts and soil moisture is generally better in the fall.
  • Overseeding lawns in the fall gives the grass a head start. The roots have become established before winter, which greatly reduces crop loss should you have a hot, dry spring.

Methods Used for Overseeding lawns and Soil Preparation

Any method you choose to evenly distribute seed will work. The task of overseeding lawns doesn’t require expensive equipment. Smaller areas can be done by using your hands if you do not have access to a fertilizer spreader. If overseeding lawns by hand, you should first divide the amount of seed you want to spread in half. Then carefully spread half of the seed by broadcasting it over the entire area. Choose a single direction to walk while spreading the seed. Then spread the other half of the seed at a right angle to the first direction you walked in. By broadcasting the seed in two different directions you have a greater chance of getting complete coverage.

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Small hand-held rotary spreaders can also be used for small areas. They are generally inexpensive and are more precise than spreading by hand.

For larger areas, it is better to use a drop or rotary spreader. This is the same type of spreader that is used to spread lawn fertilizer. Drop spreaders, like the name sounds, drop seed directly below the spreader. The width of drop will never be wider than the spreader itself. Drop spreaders are more accurate when working around flower gardens or ponds, etc, but are not well suited for very large areas. Care must be taken to ensure you are walking in straight lines. Any swerve may result in a missed area. Overseeding lawns with a drop spreader is more work if the area is large.

I prefer a broadcast spreader for overseeding lawns. They come in various sizes from small push spreaders to larger commercial models capable of holding 100 plus pounds of seed. Depending on the spreader, you will get coverage 3 or 4 times the width of the spreader. Keep in mind that seed is very light and will not broadcast as far as fertilizer. You will need to watch carefully to make sure the seed is striking the disc at a consistent rate. If the openings in the bottom of the hopper are too small for the seed size, it could easily clog. If this happens, increase the size of the opening in the hopper and walk a little faster to compensate. Also, try to spread the seed when the air is calm. Overseeding lawns even with a small breeze is all that is needed to prevent an even spread.

Preparing the Grass and Soil for Overseeding

For seed to germinate it needs to come in contact with the soil. Seed will not germinate if it is resting on grass or grass clipping, leaves, moss, or any other material. It may help to mow your lawn to 2 inches or lower and collect the grass clippings. If grass clippings from previous mowings are covering the soil surface, you may need to rake the grass before applying seed. A metal rake is best, making sure the tines are scratching the soil surface. This will lift excess clipping or debris so the soil is exposed.

Core Aeration

Before overseeding is the perfect time to core aerate. Core aeration is the process of pulling out a plug of grass and soil approximately one half inch wide and three inches long. Walk behind, motorized core aerators are very heavy machines, some weighing several hundred pounds and take a little practice to use efficiently. Aerators can be rented at many equipment rental stores. Non-motorized, pull-behind types can be purchased at home and garden stores. Heavy watering or rain should precede aeration for effective core depth. Even the heaviest aerators have difficulty penetrating dry ground.

The removal of a plug during aeration relieves soil compaction, while increasing gas exchange and water availability to the roots. Two or three passes with the aerator in different directions is best. Don’t worry about picking up the plugs; they can be left on the surface to breakdown naturally. In a few weeks they will be gone.

Core aeration is not the same thing as spike aeration. Spike aerators do not pull a plug, but will simply punch a hole in the ground. On the down side it may slightly increase soil compaction, but at the same time helps air and moisture reach the roots.

Raking is hard work, so another method is to use a pull-behind dethatcher. This is a device with dozens of metal tines that drag across the soil.

These models are designed to attach to the back of a riding mower. The tray on top of the dethatcher can be weighted down with sand bags or cinder blocks for deeper tine penetration into the soil. I prefer sand bags instead of cinder blocks, since bags don’t fall off as easily. Tie them down if necessary.

To make you own bags, take a old car or truck tube and cut them into eighteen inch lengths. Use wire to close one end and fill the bag with sand or gravel. Wire the other end closed and you have a cheap weight that works great.

Make sure you use enough weight so the tines scratch at least an eighth of an inch deep into the soil. In dry weather you will need to water thoroughly before using the dethatcher. After going over the lawn several times in different directions use a mower with a bagging system to remove debris pulled up by the dethatcher.

Keep in mind that dethaching will pull up a lot of dead and green grass. Grass clipping left on the lawn after mowing can form a thick mat. dethatching will remove much of this. The photo shows a fescue lawn and the amount of grass that is pulled up in just a few square inches of lawn. This does not hurt the grass.

Stoloniferous grasses, grass that spreads by runners, add another degree of difficulty in ensuring you are digging deep enough to remove thatch. Cutting through the stolons will not hurt the grass. The daughter plants along the stolon will continue to grow normally because they have their own root system.

Stoloniferous grasses are mostly associated with warm season grasses. Most cool season grasses, with the exception of rough bluegrass, do not produce a lot of stolons. The few that do produce stolons are fairly short.

You can also rent a motorized seeder for use in overseeding lawns. Seeders have several adjustable vertical blades that cut lines into the soil. Most have a built-in hopper that drops seed at the same time that it is making the cuts. The idea is that some of the seed will fall into the cuts, making good contact with the soil. The more expensive machines drop seed into the cuts and now where else. I have owned and used these machines and can tell you that seeders work best on flat and level ground that is relatively rock free. Flat and level means the ground has few holes, dips or mounds. The blades glide over dips without even scratching the surface, while digging deep groves into small mounds. Rocks will dull the blades quickly.

Choosing the Right Seed

Before overseeding a lawn, it is important to choose a seed that is compatible with your grass. You should try to use a seed that is the same as your grass. For example, if you have turf-type tall fescue, then use turf-type tall fescue seed or a blend of turf-type tall fescue seed and Kentucky bluegrass seed. Be careful about using bargain store seed brands for overseeding lawns. Bargain seed is often poor quality and can contain multiple undesirable varieties.

Overseeding Fescue Lawns

Fescue Rule: An important rule is if you have a turf-type tall fescue lawn, do not overseed with a coarse type tall fescue seed. Coarse fescue varieties, such as Kentucky 31 Tall Fescue or Alta are much larger plants having wider blades that were originally designed as pasture grass. They are often sold as lawn grass seed to those who do not know the difference. Stick with turf-type tall fescue if that is what you already have.

It is okay to combine bluegrass seed with turf-type tall fescue seed. Many professional seed blends use both because blades are similar in size and appearance and bluegrass spreads filling in gaps. However, the popular Kentucky bluegrass seed found in many seed bags is from an older variety of bluegrass that can’t take routine fertilization. It becomes very disease prone under high maintenance. If you fertilize regularly, ask to be sure it is an improved variety that can handle fertilization.

Important Note on Turf-Type Tall Fescue

If you want the best looking grass, be sure to use a turf type blend. The turf blends are the varieties that are being improved for appearance and deep green color as well as disease resistance qualities. If you choose a pasture grass, such as Kentucky 31, you are missing out on all the science and genetic improvements that will give you a much better looking lawn.

In addition, you get several different varieties in a single bag of turf-type so if one variety doesn’t do well in your location or soil conditions, one of the others will. You don’t get that with pasture fescue varieties.

Overseeding Lawns Using Fine Fescue Seed

Be careful when using fine fescue grass seed. The varieties of fine fescue in the U.S. are used primarily as a shade grass. It cannot survive in full sun except in places with year around cool climates. There are not many places like that in the U.S. For this reason it is marketed and sold as a shade grass. Varieties include creeping red fescue, chewings fescue, sheep fescue, and hard fescue. However, fine fescue varieties are often included in fescue seed blends because the grass will do well on shady sides of houses or under shade trees better than other grasses. Overseeding lawns using only fine fescue seed is not recommended, but is okay when combined with other seed varieties.

Overseeding Lawns with Bluegrass Seed

Most bluegrass species spread by underground stems called rhizomes. The most popular seed type is Kentucky Bluegrass seed. The rhizomes sprout at various points along the stem producing a new plant identical to the mother plant. Each new plant will send out rhizomes that produce even more plants. Because of the way it spreads, healthy bluegrass lawns rarely need overseeding. Bluegrass is often included in some tall fescue seed blends.

Keep in mind that Kentucky bluegrass can become disease prone if fertilized several times a year. It does well with infrequent fertilization. The improved varieties were designed to grow under more intense fertilization and are used by golf courses and well maintained home lawns.

Ryegrass Seed Mixtures

Lawns consisting solely of ryegrass are rare in the U.S. except in the transition zone. Ryegrass is usually combined with other seed types.

Perennial Ryegrass is popular in many seed mixtures, but is rarely used as a stand alone grass. It has poor cold and poor high heat tolerance. It is sometimes blended with fescue or used to overseed dormant bermudagrass lawns.

Annual ryegrass will only live for a year before it dies. Unless you desire a temporary grass, make sure you use a quality perennial ryegrass seed variety. Some lawn seed companies will blend annual ryegrass seed into the mixture because it germinates in only a few days providing a quick cover crop until the perennial varieties becomes established. Bargain ryegrass seed blends will often contain large amounts of annual ryegrass seed because of its low cost. It looks good for a while until it dies back leaving the home owner wondering what happened. It is better to spend a little more and get a higher quality seed blend.

Annual ryegrass is generally reserved for overseeding dormant warm season grasses or as a cover crop. This annual grass dies as the warm season grass starts emerging from dormancy in the spring. Annual grasses must be reseeded every year.

Overseeding Bermudagrass Lawns with Cool Season Grass Seed

Overseeding lawns containing Bermudagrass is common in the south. By using a cool season grass seed variety the lawns retains a green color throughout winter. Annual ryegrass, perennial ryegrass and turf-type tall fescue or bluegrass are often used. Do not use Kentucky 31 tall fescue or other coarse fescue blends for overseeding lawns. The coarse fescues are larger and taller growing plants that do not blend well in bermudagrass.

Establishing Warm season Grasses from Seed

Some varieties of warm season grasses can be established by seed. Soil preparation is the same for all grass seed. Be aware that seed of many varieties are much smaller than their cool season cousins, which makes spreading more difficult. If the seed is extremely small, mix the seed with at least an equal portion of sand. The amount of sand doesn’t really matter, so use an amount that is easiest. For example, you can use one part seed to four parts sand. Measure out the amount of seed you need for the size of the area you are seeding. Mix the seed thoroughly with the sand, pour the mix into the spreader and evenly distribute the seed/sand mixture over your lawn.

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If you are only wanting to fix thin areas in your lawn, correct the conditions that created the problems first. You may need to relieve soil compaction, fix water drainage problems, etc. Using sprigs or plugs to fix damaged areas will fill in faster than when using seed. For small damaged areas, use sprigs from your lawn and transplant in areas to be fixed.

Warm season grasses should be seeded or sprigged in the spring. Don’t mix varieties, such as bermudagrass and zoysiagrass or centepedegrass and St. Augustinegrass, etc. Due to the way warm season grasses spread, they will try to complete with each other. They have different cold and heat tolerances as well. The more aggressive one will usually win.

How Much Seed To Apply

The amount needed for overseeding lawns are usually recorded on the label. It is different with different seed varieties. The rates can be adjusted depending on the thickness of your lawn. If you currently overseed on an annual basis, less seed is preferred.

  • Use 2 to 4 lbs per 1000 sq. ft if your lawns is thick already. It is more of a maintenance activity for thicker lawns.
  • When overseeding lawns with open dirt areas and other trouble spots, use 4 to 8 lbs per 1000 sq. ft.
  • For complete renovation, 8 to 12 lbs per 1000 sq. ft. may be needed.
  • Make sure you follow good irrigation techniques for the best results. It may take a couple of years, overseeding each year, for the lawn to look it best.
  • Remember a key point when overseeding lawns: Try not to apply too much seed, and I emphasize “too much“. Thick, vibrant lawns are created over time as plants grow and enlarge. Applying so much seed in an attempt get a super thick lawn in three months may lead to overcrowding as plants mature.

Golf courses often use 15 to 30 lbs of seed when overseeding important areas. Why? Because they have an extremely high user expectation. They don’t have the luxury of “allowing it to grow in over time.” They know how much of a particular seed the turf can handle. Don’t try to follow their example or you may create problems for yourself.

Some websites will tell you to double or triple the recommended rates. Some even say when overseeding an established lawn that you should use double the rate of seed recommended for planting a brand new lawn. I don’t agree with this advice. They are assuming that the homeowner is not going to water correctly. The problem is if you do water correctly and get good germination, you can easily end up with to too much grass. Even if you use triple the rate, but fail to water, you can still lose the lawn. A lot of work is required for overseeding lawns correctly, so be determined to pay careful attention to how you water. You can measure out more seed if you really believe you need it.

Maintenance that Follows Overseeding

Keeping the Seeds Moist

After overseeding your lawn, the seeds will need moisture to germinate. Keep the soil moist (but not overly wet) by lightly sprinkling two to three times a day throughout the required germination period. Once your grass begins sprouting, you can cut down on the amount of water. Instead, water less frequently, but a little deeper. Be careful not to soak the soil repeatedly or you could encourage root rot diseases. As the grass grows, allow the soil to dry slightly before watering again. The greatest danger to seedlings is overwatering and soaking the soil, which could lead to disease (root rot) problems or underwatering and drying out the tiny roots. The second greatest problem is if you have high heat periods that cook the tender roots should the ground get too dry.

To Cover or Not to Cover Seeds

Generally when overseeding lawns, the existing grass provides cover and shade. In poor lawns with lots of exposed dirt, the soil will need to be raked to cover the seed with a thin layer of dirt.

If you plan to spread compost, apply the compost first and then seed. This is to make sure you don’t bury the seed too deep. After seeding, Rake the seed so the compost lightly covers the seed. There are also various seed coverings that shade the soil and reduce evaporation. The least expensive may be wheat straw. There is no magic to it, so just lightly spread a layer of straw over the lawn. With a light breeze you can use the wind to your advantage. The wind can catch the straw and distribute it evenly over ten feet or so. You will always get some wheat that germinates, but wheat can’t take repeated mowing. After a few cuttings, it will dieback and disappear. You may need to remove the straw after the grass starts growing if it was applied too thick.

Most professional turf mangers will spread seed after mowing and soil preparation. Some rake it in and some don’t, but it is always better to cover the seed with a thin layer of soil. Don’t mow again until the seed germinates and reaches at least two inches. It may take two to three weeks, depending on the seed type. If you mow before the seed germinates, you run the risk of picking up loose seed. Remember, contact with the soil and moisture is most important.

Using a Starter Fertilizer

When overseeding lawns, you may find it necessary to apply a starter fertilizer before or directly after seeding. This is especially true if a soil test says your soil Phosphorus (P) is low. Starter fertilizers will contain higher amounts of phosphorus (Middle number on the bag of fertilizer).

The reason for the increase is because phosphorus is relatively immovable in the soil. The soil may contain plenty of phosphorus already, but since it doesn’t move or leach, it may not be where the tiny roots can reach it. The only drawback to adding (P) is that weed seeds will benefit from the added phosphorus as well. However, when you remember that a thick turf is your best defense against weeds, added phosphorus will only help you achieve your goals. For a better understanding of how phosphorus and other nutrients works in plants, click on this link, Understanding the Soil Analysis Report.

Tall Fescue Grass
Tall fescue is an exceptional cool season grass. It is preferred by many because of its dark green color, wear resistance and heat tolerance. Click here to find out everything you need to know about tall fescue.

Kentucky Bluegrass
Kentucky bluegrass is one of the most popular of all cool season grasses. It is used on lawns, fairways and athletic fields in the cooler areas of the U.S. Find out what makes this grass so special.

Annual and Perennial Ryegrass
Ryegrass has come a long way with the introduction of new turf species. See all the pros and cons about using the perennial and annual varieties.

Introduction to Warm Season Grasses
Warm season grasses include Bermudagrass, Zoysiagrass, Centipedegrass, St. Augustinegrass and others. Here is everything you need to know about these grasses, tips and techniques, and maintenance practices.

Watering a New Lawn
Watering a new lawn is very different from watering a mature lawn. When planting a new lawn, success will be greatly increased by learning proper watering techniques.

Lawn Winerization Tips and Techniques
Fall winterization is the most important time for fertilizing cool season grasses. Warm season grasses do not receive the same treatment. Find everything you need to know to winterize both cool and warm season grasses.

Why Overseed?

Give your lawn thicker growth, better color, and greater resistance to disease and drought!

WHAT IS OVERSEEDING?

Overseeding is the planting of grass seed directly into existing turf, without tearing up the turf, or the soil. It’s an easy way to fill in bare spots, improve the density of turf, establish improved grass varieties and enhance your lawn’s color.

If a lawn looks old, or just “worn out,” if it needs growing amounts of water and fertilizer to thrive, or is disease or insect prone, it’s a perfect candidate for overseeding.

THE BENEFITS OF OVERSEEDING

Many older lawns were established with common type turf grasses not suited for the needs of today’s homeowner. They’re often more disease and insect prone, requiring more fertilizer and water.

Overseeding newer turfgrass varieties into an older lawn can help it better withstand insects, disease, drought, shady conditions and heavy traffic. The investment in overseeding pays off by reducing the amount of fertilizer, water and pesticides required. Most importantly, a renovated lawn stays greener and looks thicker and healthier!

BEFORE YOU OVERSEED

For various reasons, old turf sometimes deteriorates dramatically or dies out completely. Overseeding with an improved grass seed mixture can get new turf growing in bare areas as well as “sprucing up” areas where the turf is thin and unhealthy looking.

First, however, you must analyze the problems that caused the original turf to deteriorate. It might be due to conditions that, if not corrected, will eventually cause the overseeded lawn to deteriorate, too.

Correctable problems include:

  • Poor soil condition
  • Improper drainage
  • Soil compaction
  • Insufficient water
  • Poor fertility
  • Poor air circulation
  • Insufficient sunlight
  • Excess thatch
  • Grass varieties not suitable for the area
  • General neglect

If you have trouble identifying the problem, ask your local lawn professionals or your county extension office. The main thing is to correct the problem before you establish new grass.

OVERSEEDING METHODS

Slit-seeding with a mechanical slit-seeder

This is the best method for overseeding established turf. Slit-seeders such as the Ryan® Mataway®Overseeder have verticutting blades that cut through the thatch layer and open up a slit or miniature furrow in the soil. The depth of the slit or miniature furrow is based on the type of grass seed used. A general rule of thumb is to go no deeper than half the length of the grass seed husk. The slit-seeding unit should have concave disk blades that follow in the slits and keep them open while the seed is dropped; it ensures the seed gets into the soil where it can germinate.

Slit-seeding generally takes less seed than broadcast seeding, because most of the seed gets into the soil so it can germinate. More seed-to-soil contact means a higher germination rate and a thicker better looking new turf.

We recommend making two passes with the Ryan ® Mataway ® Overseeder, seeding at 50% of the recommended rate. Make the two passes at a 45° angle to each other, leaving a diamond-shaped pattern (see illustration). This method is fast, and results in the seed being placed a maximum of 2 inches apart.

A “full” cover will be produced faster, even with grasses that do not spread. Some overseeders drop seed in 3-inch rows which will give a striped appearance to the lawn.

Note: Before overseeding, check your lawn for thatch. If the thatch is more than 1/2-inch thick, dethatch before seeding. This can be done effectively with the Ryan ® Mataway ® Dethatcher or the Power Rake.

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Broadcast seed with a cyclone or drop-type seeder

This second method of overseeding is also effective, if you’re unable to use a slit-seeder. Aerate several times before broadcasting seed; aeration holes should be spaced not more than 2-3 inches apart. Use core-type aerating tines that remove soil plugs for better seed-to-soil contact. After overseeding, give the area a heavy watering right away to wash seed into the aeration holes and help break up the aeration cores on the surface.

One challenge with broadcast seeding is that much of the seed gets “hung up” in the thatch layer and does not get into the soil where it can germinate. Be sure to use grasses (such as bluegrass) that have a “creeping” growth method to ensure even growth; grass types that do not spread will grow in the aeration holes only and give the turf a “clump” or “spotted” look. Remember broadcast seeding requires more grass seed and the germination rate is not as high as with slit-seeding.

WHAT ABOUT CARE AFTER OVERSEEDING?

Depending on conditions and type of seed, new grass seed will begin to emerge in 5-7 days after seeding when moisture and soil temperatures are adequate. An overseeded lawn can be fully established in eight weeks or less.

Proper watering is critical to successful overseeding. The following is a recommended watering program.

  • Immediately after overseeding: Water heavily to wash grass seeds into slits.
  • Until grass seeds germinate (first 10-14 days): Water lightly on a daily basis, soaking first one inch of soil.
  • After germination: Water less frequently, but allow for deeper soaking and penetration into soil. This encourages deeper root growth.
  • After grass becomes established: Water at the recommended level for the type of grass planted.

The key is care and patience. Proper overseeding will produce a healthier, better-looking lawn that responds better to mowing, fertilizing and watering. An added benefit is increased property value!

CASE STUDY

The following photographs show a complete renovation that was done using proper overseeding equipment and procedures.

April 21
Home lawn, 25 years old. Overrun with fescue. Homeowners desired bluegrass. Roundup ® Pro was applied to kill remaining growth

May 13
Slit seeded lawn.80% Kentucky Bluegrass was planted in rows. Light watering began immediately.

May 28
Two weeks later, the germination rate is excellent. The row-crop effect of the slit-seeder fills nicely.

June 18
After 5 weeks, the lawn is filling in nicely. Customers are very satisfied with their decision to overseed.

WHEN IS THE BEST TIME TO OVERSEED?

Late summer or early fall is the best time to overseed lawns. Soil and atmospheric temperatures are most favorable for optimum seed germination and growth. With adequate moisture, fertilizer and sunlight, the new seedlings will be well established before cooler fall weather sets in. Also, weed competition is less of a factor at this time, giving the grass seedlings a better environment to grow and develop.

Spring overseeding risks the chance of weather-related problems (heavy spring rains, unexpected high temperatures) and weed competition. Also, spring seeding may interfere with the application of preemergent crabgrass or broadleaf weed killers; concurrent application of seed and herbicides is generally not recommended because the herbicides may cause poor seedling establishment. It is best to delay herbicide treatment 4-6 weeks after new grass seed germinates. If you choose to overseed in the spring, be sure to follow proper seeding and treatment practices.

Midsummer overseeding faces greater chances of disease, heat and drought stress, and weed competition. Proper weed control and adequate irrigation are musts if overseeding is attempted in midsummer.

Dormant overseeding involves seeding in late fall or early winter, after soil temperatures are low enough to prevent seed germination.

Success usually requires good snow cover during the winter, to prevent wind or water erosion and ensure germination doesn’t begin too early. This method is sometimes preferred over spring seeding, especially in northern areas, because you don’t have to wait for soil or moisture conditions to improve before overseeding.

Note: When overseeding Bermudagrass in southern parts of the U.S., late spring or early summer seeding usually works best. Bermudagrass and other warm-season grasses need warmer weather to germinate and fully develop.

Areas of Turfgrass Adaptation
Cool Season Turfgrasses, Northern Turf Program
Kentucky Bluegrass, Perennial Ryegrass, Fine Fescue
Transition Zone, MidSouth Products
Tall Fescue, Zoysiagrass; Common Bermudagrass
Warm Season Turfgrasses, Southern Overseeding Products
Tall Fescues, Hybrid Bermudagrasses, Common Bermudagrass, Bahiagrass, St. Augustingrass, Centipedegrass

WHAT TYPE OF GRASS SEED IS BEST?

Your choice of grass is generally determined by your area’s climate. Cool-season grasses, such as Kentucky Bluegrass, Perennial Ryegrass, Bentgrass and the Fine Fescues, are used primarily in western, northern and eastern areas of the United States. They tolerate moderate summertime temperatures but will also survive severe cold associated with northern winter conditions.

Warm-season grasses, such as Bermudagrass, Centipedegrass and Bahiagrass, are used in the south, southeast, and southwest United States. They’ll withstand extreme heat, but are unable to tolerate sustained temperatures well below freezing. Tall Fescues are used extensively in the midsouth and west regions and with the advent of new turf-type Tall Fescues, their use is expanding into other geographic areas as well. For detailed recommendations, contact your lawn care professional or county extension agent.

Do you need to start over?
Proper overseeding can renovate a lawn if it has at least 50% or more healthy turf. However, if your lawn has less than 50% healthy turf, it may be better to kill out the old turf, weeds, etc., and reseed the entire lawn.

RECOMMENDED STEPS FOR COMPLETE RENOVATION

  1. Apply a chemical such as Glyphosate (Roundup ® ) to kill all vegetation.
    • Apply at the recommended rate, when grass and weeds are actively growing.
    • Don’t spray when rainfall is expected within 24 hours.
    • Don’t spray when windy, to avoid drift onto shrubs, trees, neighboring lawns, etc.
    • Don’t walk from treated onto untreated areas.
    • Allow Glyphosate to work for 7-10 days before starting follow-up renovation steps.
  2. Use a power rake to dethatch and remove excess (1/2 inch or more) thatch debris from the treated lawn.
  3. Aerate thoroughly, using a core-type aerator.
  4. Fertilize with a good starter fertilizer. Apply at the recommended rate.
  5. Re-seed, using a mechanical “slit seeder.”

Tip: Reduce the recommended seeding rate by one-half and cover the area twice, in two directions, leaving a “cross-hatch” seeded pattern at a 45º angle. (See previous illustration above)

Note: Whether or not a chemical such as Glyphosate is used, it usually works better to overseed new grass into the old, undisturbed turf, even if it is dead, rather than start with bare dirt. Overseeding is faster and easier than completely digging up the soil, and it leaves some cover to protect against wind or water erosion of the soil surface.

USEFUL DEFINITIONS

Aerification: The process of improving the movement of air, water and nutrients into or within the soil, usually by removing soil plugs or cores. Also performed to relieve compaction of soils.

Annual grass: Any plant which germinates, matures, produces seed and dies within one growing season.

Bahiagrass: A coarse-textured, low-maintenance warm-season grass which is primarily regarded as a clump grass but also spreads by rhizomes.

Bentgrass: A cool-season grass of fine-to-medium texture with stoloniferous growth. Used primarily on golf course greens, tees and fairways.

Bermudagrass: A popular warm-season grass of fine-to-medium texture with vigorous growth from rhizomes and stolons. Quite often planted for sod production.

Bluegrass: A popular cool-season grass of fine-to-medium texture with vegetative growth by rhizomes and tillers. Quite often grown for sod production. A popular component in most grass seed mixtures.

Broadcast seeding: The process of scattering seed over the soil surface or onto an existing turf surface, using a rotary or gravity feed-type spreader. Generally acceptable for seeding new areas, but not recommended for overseeding purposes.

Bunch-type growth: Plant development by tillering at or near the soil surface without production of rhizomes or stolons.

Centipedegrass: A warm-season, medium-to-coarse texture stoloniferous grass which grows best on acid soils.

Cool-season turfgrass: A turfgrass adapted to rapid growth during cool, moist periods of the year. Plants can be injured, or will enter dormancy during prolonged periods of hot weather.

Creeping growth habit: Plant development by stem growth at or near the soil surface, by the spreading of
rhizomes and/or stolons.

Dethatch: The procedure of removing an excessive thatch accumulation mechanically by practices such as vertical mowing or core aerification.

Dormant seeding: Planting seed during late fall or early winter after temperatures become too cold for seed
germination. Seed germinates the following spring when the soil warms.

Dormant turf: Areas which have temporarily ceased growth as a result of extended drought, heat or cold stress, but are capable of resuming growth when environmental conditions are favorable.

Fine fescue: Fine-textured, cool-season grasses reproducing vegetatively by tillers or rhizomes. Generally do well in shaded and low-fertility conditions. Includes creeping red fescue, chewings fescue and hard fescue.

Germination: The beginning of visible growth of a plant as it emerges from the seed.

Hydroseeding: A process in which a slurry consisting of water, grass seed, mulch and/or fertilizer is pumped through a nozzle and sprayed onto a seedbed.

Overseeding: The process of seeding new, improved grasses into worn-out or damaged turf. Used for rejuvenating existing turf with minimal disturbance to the soil or grass.

Pesticide: Any chemical agent used to control pests. This would include fungicides, herbicides, insecticides, etc.

Preemergent herbicide: A herbicide which prevents seedling emergence or growth of a plant.

Renovation: Turf improvement involving replanting into existing live and/or dead vegetation.

Rhizome: An underground stem which is capable of producing a new plant similar in all respects to the parent plant.

Root system: The underground, downward growth of a plant; anchors plants into the soil and absorbs moisture and nutrients from the soil for use by the entire plant.

Root zone: The area of the soil where roots develop, grow and mature.

Ryegrass: Annual ryegrass is used primarily as a nurse grass. It is coarse-textured and persists for only one growing season. Perennial ryegrass is a fine-to-medium textured, cool-season grass generally known for its fast rate of establishment and excellent traffic tolerance.

Slit-seeder: A mechanical seeder capable of cutting grooves into the soil, followed by the placement of seed into the grooves, assuring good seed-to-soil contact. Recommended for overseeding into existing turf.

Spot seeding: The seeding of small, usually barren or sparsely-covered areas within an established turf.

Spray drift: The movement of airborne spray particles from a spray nozzle outside the intended contact area.

Stolon: A stem growing along the soil surface which is capable of taking root and starting a new plant at each node.

Stress: A condition under which a plant suffers due to a lack of moisture, food, extreme heat, extreme cold or a combination of external factors.

Thatch: A loose, intermingled layer of dead and living shoots, stems and roots that develops between the zone of green vegetation and the soil surface.

Tiller: A sprout or stalk that forms its own leaves and originates at the base of the parent plant.

Topdressing: A prepared soil mix added to the surface of the turf and worked in by brooming, matting, raking and/or irrigation for the purpose of controlling thatch-forming materials, enhancing thatch decomposition and covering seed after planting.

Vertical mower: Also referred to as a Power Rake. A mechanical device having vertically rotating blades that cut perpendicularly into the turf for the purpose of controlling thatch.

Warm-season turfgrass: A turf species that is widely distributed throughout the warm-humid or warm semi-arid climates of the south; usually dormant during cool, wintertime temperatures.