When To Fertilize New Grass Quick Optimal Results

If you have recently seeded your yard, it is crucial to fertilize so your grass will grow into a green and lush lawn.

A new lawn is not as resistant to disease or harsh weather as a well-established one.

It is important to fertilize your new lawn, so the grassroots can grow deep into the soil for healthier grass.

So when is the best time to fertilize a new lawn?

Ideally, you will use a starter fertilizer in the soil before planting your grass seed or laying sod to give your lawn a healthy start. After 6-8 weeks of planting your new grass, use a traditional nitrogen-rich fertilizer for continued healthy growth.

It is essential to wait a minimum of 4-6 weeks, but waiting for 6-8 weeks before fertilizing is best, especially if you have added a starter fertilizer to the soil initially.

Fertilizing your lawn too often will burn your grass, and the excess fertilizer will leach into the water table.

Read on to learn more about fertilizing your new lawn for the best results without causing any damage to your grass.

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Why Do You Need To Fertilize Your Lawn?

Fertilizers improve the health of your soil by adding nutrients essential for plant growth.

When the soil is healthy, it becomes more resistant to pests, weeds, erosion, and the chance of disease.

If your soil does not have the proper nutrients, your grass will have a harder time growing.

While healthy soil is a good thing when you want your grass to grow, fertilizing too often will have detrimental effects on your otherwise healthy lawn.

If the ground is too saturated with fertilizer, the excess chemicals will leach into the local water table and possibly runoff into nearby ponds and streams.

These chemicals are often the cause of toxic algae blooms in ponds and lakes, which are harmful to the wildlife in the area.

Overfertilizing will also cause burns to your grass, possibly killing it.

Establishing a fertilizing schedule for the year is important, so it will be more difficult to overdo it.

Choosing The Best Fertilizer For New Grass

When you have new grass, it is best to choose a regular fertilizer with high nitrogen and phosphorus.

Nitrogen helps to keep your grass lush and green, and phosphorus aids in nutrient absorption.

Potassium is another essential nutrient that will benefit your grass by making it more resistant to disease and improving water absorption.

Understanding the grass you have will also help you choose the best fertilizer for your lawn.

Different types of grasses have varying nutritional needs, so choosing the right one is essential for the overall health of your lawn.

Without the right fertilizer, your lawn will be more prone to yard fungus, and its growth will be stunted.

For new lawns, your best option is to choose a fast-release fertilizer.

A lawn starter fertilizer is a quick-release type of fertilizer used only on new lawns.

The nitrogen, phosphorus, and potassium ratio, commonly known as the NPK, will be 20-20-10. 

This means the fertilizer has 20 parts nitrogen, 20 parts phosphorus, and ten parts potassium.

The high phosphorus level will increase grass growth and offer more protection against fungus and disease.

Once the lawn is established, you will need to use a fertilizer with an NPK ratio of 20-5-5.

It is best to use a slow-release nitrogen fertilizer with established lawns for ongoing grass maintenance.

Since the fertilizer is slow acting, the nutrients are released over time, and you only have to fertilize your lawn 2-3 times per year.

Understanding The Nutrients In Lawn Fertilizer

The three main components in any lawn fertilizer are nitrogen, phosphorus, and potassium.

Each of these nutrients plays a crucial role in keeping your grass lush and green.

Nitrogen helps grass grow, and it is the nutrient that gives your lawn its vibrant green color.

The quick-release nitrogen will also allow the grass seeds to absorb more potassium.

Phosphorus encourages healthy root growth, which is very important for new lawns.

Longer roots allow grass to absorb more nutrients, retain water, and prevent the grass from being easily uprooted.

Potassium makes grass hardy and resistant to disease and inclement weather.

The potassium in fertilizer also helps the plant cells absorb more nitrogen.

Using a quick-release fertilizer on a new lawn makes the nutrients more available for the grassroots and seeds.

Once your lawn has established itself, you will choose a slow-release fertilizer with less phosphorus and potassium.

The Different Types Of Fertilizer For Lawns

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In addition to choosing a fertilizer with the correct NPK ratio, the composition of the fertilizer is also important.

The type of fertilizer you choose will greatly depend on the acidity of your soil and whether or not your lawn requires a quick-release or slow-release product.

Organic Fertilizer

Organic fertilizers are made from plant and animal materials.

These ingredients may be derived from manure, rock phosphate, blood meal, fish by-products, and cottonseed meal.

Organic fertilizers are slow-release, which makes them an excellent choice to use in the fall.

Grass clippings are a cheap and easy organic fertilizer, and their high nitrogen content will give your grass the nourishment it needs to stay healthy and green.

Compost is also a great choice of organic fertilizer, and it is used as a top dressing for lawns.

It is recommended to cover your lawn with a layer of compost once every 2-3 years to add additional nutrients to the soil.

If you want to buy some, check out this organic fertilizer for a safe and natural product.

Chemical Fertilizer

Chemical fertilizers consist of animal, petroleum, and mineral by-products.

The nutrients in chemical fertilizers are usually highly concentrated on working quickly with better absorption.

For chemical fertilizers, it doesn’t get much better than Scotts Weed and Feed lawn builder.

Urea Fertilizer

Urea fertilizers are ammonia-based, and they tend to be less expensive than other types of fertilizers.

Urea fertilizer is also quick-release and high in nitrogen.

You will need to mix the urea fertilizer with the soil to prevent losing essential gasses as they convert to nitrogen.

Urea fertilizer is an excellent choice for grasses needing an acidic type of soil.

Urea fertilizer is based on animal droppings. 

Ammonium Sulfate Fertilizer

Ammonium sulfate fertilizers are used in soils with high alkalinity.

These types of fertilizers work by adding sulfur to lower the soil’s pH.

Ammonium sulfate fertilizers need to be diluted with water before application or used as a top dressing for your lawn.

When To Fertilize Your Lawn

Around 4-6 weeks after your grass sprouts, you will need to establish a fertilizing routine for your lawn.

You may either use a broadcast spreader or a handheld spreader in the application of fertilizer.

Broadcast spreaders are generally preferred over the handheld kind because they allow for more even distribution of the fertilizer.

When the grass begins to turn green in the spring, it is advisable to mow the lawn at least twice before fertilizing for the first time in the growing season.

Depending on the weather in your area, you will be fertilizing your lawn between early March and the middle of April.

It is also important to fertilize your lawn in the fall before the first frost.

Applying fertilizer in the fall protects your grass from colder temperatures and allows your grass to recover more efficiently when the weather gets warmer in the spring.

If you are starting your lawn from seed, use a starter fertilizer for the initial application.

Once the seeds have germinated and sprouted for 4-6 weeks, switch to a slow-release fertilizer.

It is essential to fertilize your new grass after this brief growth period to ensure your lawn is getting enough nutrients.

The new grass seedlings will quickly use up the available nutrients in the soil.

If you do not fertilize your grass once it has been established, your lawn may be missing out on the vital nutrients it needs to grow and stay healthy.

Check out these tips for keeping grass seed from washing away.

Prepping Your Lawn For Fertilizer

Before you fertilize your grass for the first time, it is vital to know your lawn’s size and soil composition.

First, you need to measure the square footage of your lawn, so you will know how much fertilizer you need to apply.

Next, you will need to have your soil analyzed to determine which nutrients it may be lacking.

Having a soil test done is very easy and inexpensive, and it will give you important insight into the nutrients your soil may need.

Your soil samples will be sent to a lab, where they are analyzed for nutrients.

Determining your soil makeup will allow you to choose a fertilizer with the best NPK ratio.

Poor soil conditions are not suitable for grass growth, and you will not have the desired results you were hoping for.

When using a fertilizer containing phosphorus, extra care needs to be taken.

If too much phosphorus builds up in the soil, it will leach into the water table, where it may runoff into nearby bodies of water.

This phosphorus content will harm fish populations and increase toxic algae blooms in the water.

Tips For Maintaining A Lush, Green Lawn

Once you have established a healthy new lawn, there are a few steps to take to keep it lush and green.

One of the most common mistakes in lawn care is overfertilization.

Using the wrong type of fertilizer or fertilizing too often is harmful to your grass and often results in scorching, discoloration, and bare spots.

Choosing when to seed your lawn will also impact how well your grass grows.

For cooler climates, seed your lawn in late summer or early fall.

In the summer, the soil will still be warm, and in the fall, the grass will retain more water.

Warm soil and good water retention will encourage your new grass to germinate more quickly.

Check out our guide for watering grass seed.

In a warmer climate, it is best to seed your lawn in late spring or early summer. 

During these periods, the soil will be ready for new grass growth.

Once the rainy season starts, it will be prime conditions for your grass to germinate.

Regular removal of broadleaf weeds is essential because these weeds will compete with your grass for nutrients.

You may either remove the weeds by hand or use a lawn-safe herbicide.

Always read the label on an herbicide product to ensure it is safe to use on your type of grass.

Lastly, how you mow your lawn is crucial to the overall health of your grass.

As a general rule, it is best to follow the one-third rule when mowing your lawn.

This means you will only cut one-third of the grass length each time you mow.

Cutting your grass too short will result in discoloration and possible bare patches on your lawn.

It is best to use a push mower for a new lawn because this type of lawnmower will put less pressure on your grass than a heavier riding mower.

Commonly Asked Questions

Can I fertilize and seed at the same time?

Seeding and fertilizing simultaneously are not recommended because you may end up with an uneven application of both products.

It is better to apply a starter fertilizer to the soil before seeding your lawn.

What happens if you fertilize too early?

When grass first starts growing in the spring, it puts all of its energy into root development.

Applying fertilizer to the grass too early will cause it to focus on producing leaf growth instead.

This means the grass may have a weaker root system, which is harmful in the long run.

A weak root system will prevent the grass from absorbing more nutrients and retaining a larger amount of water.

Short roots also make the grass more susceptible to being accidentally uprooted.

Should you fertilize before or after rain?

It is best to fertilize your lawn two days after a watering session or heavy rain.

Fertilizing at least two days before it rains is also ideal.

You want your lawn to receive moisture after fertilizing, but the fertilizer may be washed away if it rains too soon after application.

Ensuring the lawn receives some type of water two days before fertilizing makes the soil moist enough to be receptive to the seeds without being too soggy.

Is it better to fertilize in the morning or evening?

It is optimal to fertilize your lawn early in the morning before the dew completely evaporates.

The cooler temperatures and the moisture from the dew lessens the chances of burning your grass.

Fertilizing or watering your lawn in the afternoon will cause any moisture to evaporate from the heat of the sun, increasing the likelihood of your grass becoming scorched.

When should you not fertilize your lawn?

If your lawn has a warm-season grass type, it will go dormant in the winter, and it is best not to fertilize it later than September.

Warm-season grass types include: 

  • St. Augustine 
  • Bermuda 
  • Bahia
  • Zoysia
  • Centipede grass

Warm-season grasses do well in areas where it does not get frost, and they grow best in temperatures ranging from 75-90° degrees Fahrenheit (32° C).