When To Fertilize New Grass For Amazing Results

Last Updated on August 24, 2021 by Grow with Bovees

When redesigning your old garden or looking for ways to improve your yellowish, patchy lawn, you’ll need a lawn fertilizer. How does it work and when do you fertilize new grass?

We answer that and more in this article. Included topics are:

  • Reasons to fertilize new grass.
  • Best types of fertilizer.
  • When should you fertilize?
  • Seeding steps.
  • Tips for lush grass.


Reasons for Fertilizing New Grass

Fertilizers consist of the most crucial nutrients that are needed when growing a new lawn. So, applying the right fertilizer into your soil before seeding the grass will offer a great boost to the process.

Here are some other scenarios when a fertilizer would be useful:

  • Lack of direct sun: Most lawns need four to six hours of direct sun to thrive.
  • Rare watering: If you can’t often water or don’t have an automatic irrigation system, then fertilizer might help make up for that.
  • Speeding things up: It’s not a secret that fertilizers are commonly used to speed up the growth rate of plants, and a new lawn is no exception.
  • Avoid lawn problems: High-quality fertilizer makes your soil more resistant to erosion, brown patches, lawn fungus, red thread, snow mold, and summer patching.

Which Is the Best Fertilizer for New Grass?

The best fertilizer for a new lawn should contain a high amount of nitrogen and phosphorus. The former will make your grass lush, vibrant, and green, while the latter will help it absorb nutrients. Potassium is another key ingredient here, as it reduces the chance of disease.

I recommend Scotts 21605 as a great new grass fertilizer. Thanks to its special formula you can expect your grass to come in around 70 percent thicker, as it grows 35 percent faster, according to the company.

It’s an excellent choice for fertilizing zoysia grass, and almost every grass type, including new or reseeding the old ones.More importantly, it has enough potassium to guard new grass and improve water absorption until it grows up.

What Is a Good Lawn Starter Fertilizer for New Grass Seed or Sod?

A good starter for new grass seed and sod would be similar to the category above. The same fertilizer, Scotts 21605, can be an appropriate option here.

What Nutrients Are in Lawn Fertilizer?

There are three primary minerals in fertilizers for enhancing grass health: nitrogen, phosphorus and potassium.

On packages, you’ll notice most companies use a ratio, otherwise known as NPK. For example, a 20-5-5 ratio means 20 percent nitrogen, 5 percent phosphorus, and 5 percent potassium.

Different fertilizers will contain various ratios designed for specific uses and types of grasses.

How Do They Help New Grass?

Fertilizer provides your soil with the right minerals that make your lawn grow fast, lush and green.

The right fertilizer will improve the overall health and appearance of your lawn and will help protect it from drought and burning.

If your grass is lacking nutrients, it may not grow at all or it could turn brown. Another possible scenario is yard fungus. That might include patches of mushrooms, slimy parts, or other uninviting characteristics.

Lawn fungus can be pesky and ruin your lawn quickly, however, the good news is that with the right treatment it’s easy to overcome.

What Do Nitrogen, Phosphorus, and Potassium Actually Do?

The three crucial ingredients in most fertilizers work as follows:

  • Nitrogen: It’s what makes your grass thick and green.
  • Phosphorus: Triggers root growth, seed expansion and mineral consumption.
  • Potassium: Shields grass from disease, drought and rough winters.

Furthermore, potassium supports the role of nitrogen, as it helps the plant cells absorb it overtime.

What Fertilizer Ratio for Established Lawns

It’s important to understand that you have to pick the appropriate fertilizer ratio for your lawn and grass type.

Is your lawn established? A NPK ratio of 20-5-5 could give it a little boost to maintain its quality throughout the year.

A slow-release fertilizer might be best here, as it’ll help with maintenance overall. Using this type of fertilizer means you shouldn’t need to fertilize more than two to three times per year.

What Fertilizer Ratio for a New Lawn

The best ratio for a new lawn is different. You’ll probably opt for a fast release fertilizer instead, with a ratio closer to 20-20-10.

As you’ll notice, the phosphorus level is higher here to give your new lawn a boost in growth. This potent ratio should provide your new grass with a longer protection period and a rich green color.

When Should I Fertilize New Grass?

The best time to fertilize new grass is around four to six weeks after the grass sprouts.

Today, there are plenty of starter fertilizers for new grass, and most of them will be nitrogen-rich. As I mentioned above, choose an NPK ratio of 20-20-10 for new grass.

How To Fertilize New Grass Seed

For best results when planting new grass seeds, use starter fertilizers with quick release nitrogen

Every fertilizer will have a label with clear instructions, but I’ll give you some extra tips on how to avoid common unwanted setbacks.

You should use a broadcast spreader to distribute your fertilizer after planting the grass seeds. This machine is efficient and the most popular option for home fertilizing jobs.

You could take the old school approach by sprinkling the fertilizer by-hand with a handheld spreader, but it’s more difficult to spread it evenly. There’s a chance for accidental over-fertilization here, as well, which can lead to dead seeds, little growth and burnt bits.

10 Steps for Seeding a New Lawn

  1. You’ll first use a weed killer for any current vegetation. After everything dies off, collect it neatly and make sure you don’t leave any remains. Read the weedkiller instructions carefully to know exactly when to seed your new lawn.
  2. If there is any sign of moles in the area, you should get rid of the moles first.
  3. Aerate the soil with your preferred tool, for example, a plug aerator or aerator shoes. Dig into your soil until about 2 to 3 inches (7.62 cm) in depth and make sure that everything is evenly aerated, meaning no clumps are left.
  4. Spread your starter fertilizer evenly across the lawn area.
  5. Cover the field with your preferred seed. Again, follow the instructions that are provided with the packaging.
  6. Grab your favorite leaf rake and gently drag it over the surface to ensure that your seeds are distributed evenly across the soil.
  7. Now, it’s time for watering, which you should do twice per day, once in the morning and evening. Be careful to avoid over watering or drenching your lawn.
  8. After your grass reaches around 3 inches (7.62 cm) in height, you can start mowing regularly.
  9. Once four to six weeks pass, you’ll apply the slow-release fertilizer.
  10. Keep an eye out for weeds as an abundance can disrupt the grass growth. Use high-quality broad leaf weed herbicide to get rid of it.
  11. Sit back and admire your work. Don’t forget to mow one or two times per week and use a slow-release fertilizer two to three times a year.

Should I Fertilize Newly Planted Grass in Fall?

You should definitely fertilize your lawn in the fall. It’s less stressful than the summertime when the grass is struggling to survive the heat.

Fertilizing in the fall provides other benefits, too:

  • Giving an extra kick for growth in the fall will result in a green, lush lawn come springtime.
  • Turf is more prone to consume fertilizer because of the dew in the autumn mornings.

Which Is the Best Slow Release Organic Lawn Fertilizer?

After looking through dozens of slow-release fertilizers, I found that Milorganite Organic Nitrogen Fertilizer is the best product available. It’ll make your grass dense and green.

The secret weapon in this fertilizer is 4 percent iron that boosts color development. It has an NPK of 5-2-0, which means it doesn’t have potassium and is purely organic.

Don’t use this fertilizer if you’re living in states where you have regular droughts because potassium is needed in this weather situation.

Actionable Tips for Lush Grass

By now, you should have a clear understanding of what type of fertilizer to use and the best times to carry out fertilizing. To make your life easier when growing new grass here are some extra tips.

Don’t Over Fertilize

The most common mistake people make when preparing their soil for new grass is that they over-fertilize it. They even fertilize too much when their grass is fully grown.

You want your lawn to be the best looking space on the block, but it does more harm than good in this scenario.

Fertilizers contain a lot of salt, and too much sodium pushes the water out of the soil. A dehydrated soil will make the grass dry out and probably cause fertilizer burn as well.

Choose the Correct Time

Perfect timing is essential when seeding new grass. Chilly climate residents should seed the new grass in late summer or early autumn.

During this time, the soil is still warm from the summer season, and in the autumn, the grass will retain more water. These are the optimal conditions for new grass to germinate faster.

On the other hand, people living in warmer climates will benefit the most from seeding new grass in late spring or early summer. At this time, the soil is prime for grass growth. Then, the rainy season kicks in, as well, making for good conditions for grass to germinate.

Mow Correctly

Have you heard of the one-third mowing rule?

There’s a general rule of thumb that says when you mow, you want to remove around one-third of the length of the grass blades.

This means that if you want your grass to grow 3 inches tall, you should mow it when it’s around 4.5 inches in height.

Quick tip: Use a Push Reel Lawn Mower when your lawn is still new. These mowers are lightweight and will put the least amount of pressure on the grass.

Fertilizing New Grass in Conclusion


Growing new grass isn’t that hard of a job when you know the actual steps. The most important thing is to apply the correct fertilizer at the right time without overusing it. When to fertilize new grass depends on your location and weather conditions.

To get the most out of your process, use a starter fertilizer with a high amount of nitrogen and phosphorus. This offers the necessary boost to grow it faster and greener.

Sooner than later, your neighbors just might be amazed at your beautiful lawn.

See also  When To Use Milorganite on Your Lawn for Best Results