Lawn Care

How to Seed a Lawn That Already Has Grass

Planting (or seeding) a lawn is not difficult. It is a simple DIY procedure that can be done successfully by anyone who chooses to. But can you seed a lawn that already has grass? The answer is yes, you can seed a lawn that already has grass too.

It is more or less the same as planting grass seed. However, unlike simple planting that is done for new lawns, this is often done to create a lush lawn, make the lawn thicker, and remove any unwanted spaces where initial seeds might have done poorly.

When Should You Seed a Lawn That Already Has Grass?

The act of seeding a lawn that already has grass is called over-seeding. The best time to over-seed your lawn is often during the fall. However, depending on the grass type on your lawn, over-seeding in the spring can often yield great results too.

If you choose to do it during the spring, do so early so you can give your seedlings enough time to mature before the onset of the summer’s heat. Remember it takes grass 5 – 30 days to germinate depending on the type. In cooler areas, it could take longer than this so be sure first.

Seed a Lawn That Already Has Grass

How Do Your Seed A Lawn That Already Has Grass?

Like we have said before, seeding a lawn is usually a simple DIY procedure. And the truth is a great lawn can only come from great grass seeds. The same applies to an overseeded lawn. Here is how to seed a lawn that already has grass.

Step I

  • Mow your lawn as short as possible.
  • Remove grass clippings and thatch.
  • Loosen the top soil (1/4 soil) in bare spots.
  • Take time to clear any debris and dead grass.
  • Level your lawn. Target areas where excessive water collects.
  • Use existing lawn soil to level. New soil could contain weed seeds.

Step II

  • Plant your newly bought grass seeds.
  • Spread the seed. Make sure it is evenly done. You can use the hand in small areas.
  • Use lawn spreader/ mechanical seeder to apply your new seeds in large areas.
  • Apply approximately 16 seeds per square inch this is the standard capacity.
  • Do not apply so too many grass seeds than it is recommended.

Step III

  • Cover your new seeds so well.
  • Lightly drag the grass seed bed.
  • This ensures no more than ¼ inch of soil covers the grass seed.

Step IV

  • Water your lawn often.
  • Water twice a day especially when the temps are still cool.
  • Keeping the lawn moist will enhance germination.
  • Water lightly. Do not saturate.
  • Water frequently until the new grass is two inches high.

Step V

Factors to Consider When You Seed a Lawn That Already Has Grass


Top quality grass seeds for over-seeding purposes should be NTEP rated variety. This simply means that you are using seeds that have been specifically bred for superior grass qualities in terms of color, disease and drought tolerance, and insect resistance.


Use standard seed application capacity. Too many seeds too close together cause seedlings to fight for room and the existing nutrients. This will leave grass looking weak or thin in these areas where you seed a lawn that already has grass.


Watering lightly but frequently aids the germination of new grass seeds. It also allows the quick penetration of grass roots and keeps the lawn looking green and lush. Water at least once a day when temps are cool, this can be done in the morning or late evening.


The best time to seed a lawn that already has grass is during the fall for cool season grasses. You can also over-seed very early in the spring. Do not overseed during the summer as too much heat kills grass seeds.


It is important to know the germination period of your grass. This will determine the right time to over-seed. The standard germination time frame is usually 5 – 30 days. Just know what your grass takes. Ask the grass seed vendors.


Grass clipping is removed to allow new seeds to come into contact with the soil and to get enough sunlight and water. The standard mowing before over-seeding is usually two inches or less. However, for southern lawns and winter color, it is recommended that you do scalping (set the blade as low as it goes while cutting just above the soil level).

When Can You Mow an Over-Seeded Lawn?

Many people are often worried of when they can mow the lawn after over-seeding. Well here is what you know, you should begin watering your lawn right after you overseed. Do this once or twice a day especially during the cooler parts of the day until your grass grows to mowing height.

What Difference Does Seeding have from Over-Seeding?

Seeding is simply the opposite of over-seeding. While over-seeding is done on a lawn that already has grass, seeding is done on an entirely new lawn with no signs of existing grass. Here are the main differences.

  • Seeding is done on new pure lawns while over-seeding is not.
  • Seeding requires slightly heavy watering. Over-seeding needs light watering.
  • Seeding requires a definite soil PH. Over-seeding is done with the knowledge.
  • Sand and compost are mixed to prepare the soil for seeding. Over-seeding doesn’t.
  • There is starter fertilizer for seeding purposes. Over-seeding needs grass seed accelerator.


To seed a lawn that already has grass successfully, just make sure that you keep the top ¼ inch of the soil moist. This will allow the seed stay moist always. This should spur quick germination. Also, ensure that you cover the entire over-seeded area thoroughly each time to support root growth for your newly overseeded lawn grass seeds.

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