Fertilize or overseed first is something you might be wondering about in your quest to get thicker grass in your lawn. The truth is; it doesn’t matter what you do first unless you do it right.

Complete Guides of Growing Thick Lush Grass

This guide contains the answers to all your queries about overseeding a lawn. Read and go through it to clear any confusion you might have, and keep referring to it whenever the need arises later.

Fertilize Or Overseed First?

You can fertilize first and then overseed or overseed at first and then fertilize the soil, both will give you luscious green grass, you can place them simultaneously too. As you do so, you must make sure that they are well cooperated with the soil to give you a result.

What Are the Fertilizing Aspects?

Fertilizing can be done anytime, whether it is before or even after overseeding. The key feature is to spray it first and then water it after you have fertilized it, the reason is that this will ensure the prosperity of the grass.

– Right Time

Know your grass type and climate before determining the right time for fertilizing and overseeding a lawn. Cool-season grasses reseed naturally in late summer till early fall time.

Their seeds germinate before the grass dorms and turn green when spring arrives. Warm-season grasses germinate way earlier in late spring till the beginning of summer before peak summer weather arrives.

Do you live in the southern, warmer, colder or the northern states? Depending on your regional climate and the grass planted in your lawn, you have to see whether you should re-seed it in summer or after summer to see it grow and thrive.

Keep a lookout on the weather forecast if you live someplace with harsh winters and are planning to oversee a cool grass season. Always reseed your grass almost six to eight weeks before the season’s first frost is predicted.

– Fertilize Anytime 

It doesn’t matter when you apply a lawn starter fertilizer during overseeding because you can fertilize at any time, and it will boost the growth, and produce good results. Depending on your personal preferences, three options are available. 

You can either fertilize the lawn just before overseeding or immediately afterward. You can carry out overseeding and fertilizing simultaneously to save time and energy, as you are already cooperating them. 

Use Fertilizer Whenever Grass Needed

Lastly, you can wait for a day or four after overseeding your lawn to fertilize it finally. All three options help your grass seeds instantly get the foods they need and germinate. 

You must note that the we are talking about a specialized lawn starter fertilizer here only. Ordinary fertilizers must be applied several weeks after the seeds have germinated, and the grass blades have grown longer.

– Fertilizing Before 

Fertilizing before overseeding ensures your lawn is already laden with nutrients that the new seeds will need to germinate and sprout fresh leaves.

Suppose you have only recently fertilized your established lawn within the past three to four weeks, then fertilizing before overseeding can become too much. Your established grass blades will no doubt be able to tolerate a double dose within weeks, however, the younger shoots and grass blades can get overfertilized.

Overfertilization is harmful because it leads to the development of chemical burns. Wait a month after regular fertilizing to apply a seed starter. Immediately follow up with a reseeding of the entire lawn. 

– Fertilizing After 

Fertilizing after you have spread grass seeds over a pre-established lawn is way easier and safer. This also gives you better control over your lawn and the new grass that will grow. 

You can either apply starter fertilizer right after spreading and tilling the seeds or apply it later.

Fertilizing After Seeding Grass

Take your time, though, and preferably carry out lawn feeding within the next four days

The next four to five days after spreading seeds on the lawn are when the nutrients from fertilizer are needed. If you take advantage of this window of opportunity, there is very little benefit, even if you apply a good quality fertilizer later. 

– Best Way To Fertilize The Lawn

Whether you apply fertilizer before seeding or afterward, it is best to use a spreader. Different fertilizer spreaders are available, but you only need a small hand-held one for an average-sized house lawn. 

You will need to buy a broadcast spreader for very large lawns for faster work. When opting for liquid lawn fertilizer, a sprayer will be needed.

You will also have to dilute a liquid starter feed, even if the manufacturers claim, it is safely used as a premium-quality seed starter fertilizer to get the desirable results. 

Better walk around the perimeter of the lawn and feed it first. Then divide your lawn into straight lines and fertilize them sequentially, so no spot is missed. A spreader will also ensure that your lawn is fertilized as evenly as possible.

A fertilized and overseeded lawn must be watered daily for several days afterward. In order to prevent overwatering, water the lawn only lightly and stop altogether if you feel the ground getting too mushy. Water early in the morning because after the sun comes up, most of the water is lost to evaporation, which wastes half of your efforts.


What Are the Aspects of Overseeding?

The overseeding aspects begin at the start by detaching, mowing, and raking first, then you must control the soil amendments and then reseed it. Make sure that the quality of the soil is prominent to result in the long run, and make sure you place the seeds in bold patches.

– Dethatch, Mow, and Rake First

You can overseed your lawn and get the lush, thick grass you have always wanted in just a few simple steps. The first step is to detach your soil and remove the thick layer of soil and grass built over it. Otherwise, the new seeds will not get close to the soil surface.

If detaching is not needed, then go for soil aeration. Using a lawn fork, you can manually dig three to four inches deep holes in the soil. A much easier approach would be to use a plug aerator to loosen up the soil and improve water, oxygen, and nutrient supply.

When you spread seeds over a previously established lawn, you want to ensure they come in intimate contact with the soil. For this, the old grass must be mowed as low as healthily possible, and collect grass clippings instead of spreading over as mulch.

– Soil Amendment and Reseeding

Soil amendment is not the same as adding fertilizer. It works best if you can conduct soil testing first to see if anything needs to be added. For instance, grass seeds need the soil pH to be slightly alkaline for fast germination and a healthy outcome. 

In this case, your preferred soil amendment would be to add crushed lime to the topsoil and water it deeply. If the soil lacks organic nutrients, add peat moss for clay soil and compost for sandy soils. 

Soil Amendment Before Reseeding

Using a seed spreader to oversee your chosen grass variety properly is better. Experts claim spreading an average of 16 seeds per square inch of soil is ideal for adequately thick grass.

If your lawn is already thick enough, you can have fewer seeds. If you don’t have a spreader, you can sprinkle seeds by hand and take care to avoid any spots while at it.

– Growth and Filling Patches

All turf owners with established lawns will have to carry overseeding eventually. This is because the growth of all perennial grass types slows down after a few growing seasons and reaches a steady state. 

Spreading new seeds over the ground helps produce fresh grass blades with a much faster growth rate than older ones. If your grass develops multiple empty patches and takes a long time to fill them up, then new seeds will solve this problem. 

It also helps make the grass thicker, improving its overall appearance and making it difficult for weeds to establish themselves. The development of fresh grass blades helps improve the color of the whole lawn. You will not be able to recognize your lawn after a single session of reseeding.

– Select The Best Quality Seeds

The better the quality of the seeds, the more successful your reseeding process will be. Don’t just order from any vendor online or fall prey to cheap alternatives. Trust us; you will soon see that investing in pricier seeds from reputed manufacturers is worth investing in if you set quality seeds in your soil. 

Do your research and go for hybrid seed types that produce grass with different useful qualities.

Best Quality Seeds for Thick Lush Grass

Some must-have qualities for your grass seeds are that the grass should be drought-tolerant, shade-tolerant, and able to withstand regular foot traffic on it. 

The seeds should also be pest and disease-resistant, with the ability to compete aggressively with weeds in the vicinity. How cool is it that these days you can get seeds with all these qualities that would make lawn care so much simpler.


– Will Fertilizer Kill Grass Seeds During Overseeding?

Yes, regular fertilizer kills grass seeds or at least affects their germination. That is why it is recommended to wait at least four to six weeks after regular fertilizing to reseed lawns. You always need to buy and use special lawn starter feeds for seeds. 

– What Is The Most Suitable Fertilizer For Overseeding The Lawn In Fall?

A nitrogen-rich seed starter fertilizer is the most suitable for reseeding the lawn, especially during fall. Nitrogen is the most important nutrient the seeds require to germinate. Make sure your seed starter contains other essential nutrients as well. 


Where you choose to fertilize or to overseed, it’s up to you.

Before signing off, let us recapitulate whether to fertilize or oversee first.

  • It is okay to fertilize before, during, or after overseeding as long as you use a seed starter formula and not regular fertilizer.
  • Carry out this endeavor six to eight weeks before the estimated first frost of the season.
  • It is important to water the overseeded and fertilized lawn for about five consecutive days afterward.
  • Before reseeding, make sure to mow your grass, dethatch the soil and aerate it properly.

As you are using the tips in this article above, you are already on your way to obtaining the best-looking lawn in the entire neighborhood. A little time, energy, and money regularly invested in your lawn surely goes a long way.

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