What is Starter Fertilizer?

picture of a soil and fertilizer in hand

Even if you’re a newbie to the world of lawn care or gardening, you’ve probably heard of starter fertilizer. As the name suggests, it gives your new grass or plants a big head start at the beginning of their growing season. However, homeowners often wonder if starter fertilizer is absolutely necessary – it depends! So, let’s break it down. What is starter fertilizer? How does it work? And is it really worth getting?

Healthy soil forms the foundation for healthy grass and plants, and starter fertilizer is just the ticket to get there. Starter fertilizer is a blend of different types of nutrients that helps your lawn reach its full potential. It nourishes the soil and ensures new grass seeds have the essential nutrients they need to get off on the right foot. But what kind of nutrients are we talking about here? Well, that’s where it gets interesting.

What is in starter fertilizer?

person spreading fertilizer on the soil
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When you break it down, the answer is simple. Lawn fertilizers contain three primary nutrients: nitrogen (N), phosphorous (P), and potassium (K). These three ingredients are marked on all fertilizers in the form of an NPK ratio, which looks something like 16-4-8 or 20-0-10. So look out for a set of three numbers on fertilizer products! 

Starter fertilizer for grass has those same three nutrients, but the ratio is different from regular fertilizers. Starters usually pack more phosphorous and less potassium than regular fertilizers because they are tailored to the needs of seedlings and new grass. 

  • Nitrogen (N): The extra nitrogen boosts the young grass seedlings to start them off. It’s the nutrient that helps them turn into that gorgeous green color. Usually, a starter fertilizer will contain at least 10% of N.
  • Phosphorous (P): This is the most essential component for new roots and healthy development. Because of this, most starter fertilizers contain about 20% or more phosphorous
  • Potassium (K): Potassium helps your plants be more disease-resistant, cold-resistant, and hardier overall. During early growth, your plants only need a little bit of potassium, so starter fertilizers usually contain around 5% K.

For instance, let’s say you have a brand-new lawn. The most common NPK ratio for lawn starter fertilizer is 10-10-10, which has 10% nitrogen, 10% phosphorous, and 10% potassium. However, if you run a test on your soil and find out that those levels aren’t ideal, you can mix and match different fertilizers to get the perfect ratio for your lawn. 

Starter fertilizers also come in different variations. For example, you can opt for an 18-24-12 ratio or maybe a 12-18-8 one.

As a general rule of thumb, you want to ensure that you don’t apply more than one pound of nitrogen per 1,000 square feet. This will avoid burning the grass and provide an ideal balance of nutrients. 

Here’s a quick rundown of some common starter fertilizer ratios and the amount you need to cover 1,000 square feet:

Starter fertilizer NPK ratioApplication rate of starter fertilizer (per 1,000 sq. ft.)
5-10-520.0 pounds
10-10-1010.0 pounds
16-20-06.3 pounds
20-10-105.0 pounds
18-24-125.6 pounds
12-18-88.3 pounds

On the other hand, mature grass needs different nutrient levels and will require regular fertilizer. A typical NPK ratio for established grass is 20-4-12. That’s higher in potassium and lower in phosphorous, which is what mature plants need.

How does starter fertilizer work? 

By now, you know what’s inside a starter fertilizer. But how does it work? In a nutshell, starter fertilizers provide ready-to-access nutrients to seedlings and sprouting plants. Here’s why that matters. 

When a plant is first growing, it takes time for its root system to spread and absorb nutrients. This is where the starter fertilizer comes in handy: it supplies plants with the nutrients they need but can’t yet collect from the soil (see the illustration below).

before after starter fertilizer
Photo Credit: Juan Rodriguez

As you already know, phosphorous is the star player of starter fertilizers. It gives a powerhouse boost for strong roots. Unfortunately, it is a nutrient that doesn’t move well in the soil, which is why adding more with starter fertilizer can be helpful. 

Pro tips: 

  • When applying starter fertilizer, make sure to till it about four inches into the soil to help the beneficial nutrients reach deeper into the soil, encouraging roots to grow deeper.
  • The best way to get the most out of your starter fertilizer is by applying it directly to your plants’ or lawn’s roots.

The same goes for nitrogen. Cold springtime temperatures can slow the breakdown of organic matter and delay nitrogen absorption in the soil. Starter fertilizer can give plants an extra boost of nitrogen to help them kickstart their growth. 

But nitrogen isn’t the only plant nutrient with staying power. Even though potassium, also known as potash, isn’t as crucial at this stage, it can still help your plants under marginal circumstances, protecting them from cold or wet weather. 

*Kind reminder: You don’t want to provide your seedlings with too much nitrogen or potassium – this could end up burning their root system. A soil test will give you a better understanding of the nutrients your soil and plants need.

Do you need starter fertilizer?

A healthy lawn requires dedication and patience. When getting started, you want to ensure everything is done properly so your plants don’t suffer in the long run. First things first – test the soil. By performing a soil test, you can identify pH and nutrient levels and determine if starter fertilizer is a must.

Follow all directions provided by your testing lab or DIY kit to get accurate results. If the soil test report indicates that your soil has the wrong pH or a nutrient deficiency, you can balance the nutrients by adding the appropriate starter fertilizer or soil amendments, such as lime or compost.

So, do you need starter fertilizer? That depends on the soil you have and what you’re trying to grow. Here’s a quick summary of when you should or shouldn’t use starter fertilizer. 

When to use starter fertilizer: 

  • If you’re planting a new plant or lawn from seed, sod, or grass plugs
  • In compact soils during cold temperatures
  • When dealing with low levels of phosphorous in the soil (as revealed by a soil test)
  • When your lawn is not rich in natural organic matter

When NOT to use starter fertilizer:

  • When overseeding established lawns
  • In cases of extreme temperature or drought
  • In areas with high runoff 
  • On soil that’s nutrient-rich or has lots of organic matter
  • When adjusting the pH of your soil

So, is it worth getting starter fertilizer for your lawn or garden?

While it’s not always necessary, starter fertilizer comes with its own set of perks, including:

  • Strong root development: The right phosphorus balance is essential for young roots and nutrient absorption.
  • Faster growth: An extra nitrogen boost gives young plants an advantage at the beginning of their growth. 
  • Hardiness: Potassium helps plants become more resistant to cold, pest attacks, and diseases.
  • Better fertilizer efficiency: Using a starter fertilizer reduces the amount of fertilizer you’ll need in the long run.

It’s important to point out that starter fertilizer is an additional source of nutrients for the growing seedling and not the primary one. Once the young seedling grows more roots and establishes a bigger reach within the soil, it can draw more nutrients from the soil itself, especially if the soil is already rich in organic material. 

When fully established, the root system can access nutrients in the bulk of the ground and will no longer need so much phosphorus to thrive. But starter fertilizer still has a huge role in ensuring your seedlings hit the ground running. 

Starter fertilizer vs. regular fertilizer

Now you’re probably wondering: How is starter fertilizer different from regular fertilizer? Sure, they both act as food for your plants and help promote growth, but that’s where the similarities end. 

Starter fertilizer is designed as a catalyst for new grass or plant seedlings, while regular fertilizer is there to maintain growth for healthy and mature plants. That means they don’t have the same purpose or ratio of nutrients. 

Starter fertilizer general characteristics:

  • Since starter fertilizer typically has quick-release nitrogen, it helps spread nutrients faster during the early stages of development. 
  • While it can be applied to any lawn, it’s best used with newly seeded or sodded grass. 
  • Usually, it is applied before laying the grass seed or sod, and it should be worked into the soil 4-6 inches deep.
  • Afterward, you can wait around six to eight weeks before adding regular fertilizer to your lawn.

Regular fertilizer general characteristics:

  • It has slow-release nutrients (NPK) and is mainly used to maintain the health of your grass over time. 
  • Potassium, which provides disease and insect resistance, is more important and abundant than phosphorous.  
  • Regular fertilizers are applied at least two to four times a year in the early spring and fall.

You don’t want to use regular fertilizer on a newly seeded lawn – the extra potassium and high levels of nitrogen could be too much and damage the plants.

Fertilizer types

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Fertilizers come in various types, including liquid and granular fertilizers. You can also opt for organic fertilizers, such as compost or manure. Regardless of your choice, always read the label to ensure it contains the correct nutrients. 

Granular fertilizer

Granular fertilizer is dry and often comes in the form of pellets. It’s slow-release, which means it will deliver nutrients to the grass over time. This type of fertilizer is less labor-intensive than liquid fertilizer and can last longer when stored. 

Pro Tip: Some granular fertilizers have dust, broken particles, and different-sized pellets, making it hard to distribute the nutrients evenly. Opt for products with uniform pellet sizes and minimal dust if possible.

Liquid fertilizer

Liquid fertilizers are either in the form of a concentrated fluid you need to dilute or a dry, water-soluble substance you need to dissolve. Usually, liquid fertilizer has a quick-release formula that can provide an immediate nutrient boost, making it a great lawn starter fertilizer for new grass. 

Its effects show faster than granular fertilizer. However, it usually has a shorter shelf-life and can be more expensive.

Organic vs. synthetic fertilizers

Organic fertilizer is derived from a plant or animal source, such as compost. Synthetic fertilizer, on the other hand, is made with inorganic chemicals. 

While organic fertilizer is richer in nutrients and can improve soil conditions and structure long-term, synthetic fertilizer has a more direct effect on the health of your plants. When used properly, synthetic fertilizers are safe for plants and the environment, provide essential nutrients, and are often cheaper than organic ones. However, it’s easier to over-apply synthetic fertilizer and damage your plants with fertilizer burn

FAQ about starter fertilizer

When is the best time to apply starter fertilizer?

The best time to apply starter fertilizer is usually before you sow your seeds or lay down turf. Therefore, if you are planting cool-season grasses such as tall fescue or Kentucky bluegrass, it is best to apply the starter fertilizer in early spring or early fall before you begin sowing the seeds. 

If you are planting warm-season grasses such as Bermuda or Zoysia, the best time to spread starter fertilizer is before laying the sod or planting the seeds, typically in late spring or early summer.

What is the difference between starter fertilizer and regular fertilizer?

Starter fertilizer is higher in phosphorus than regular fertilizer, which helps with root growth and development in young plants. Regular fertilizer, on the other hand, is more balanced in its nutrient content and should be used for mature plants.

What are the benefits of using starter fertilizer?

The primary benefit of using starter fertilizer is that it helps young plants with root development, allowing for better and faster root growth. However, you may also see improved color and an overall healthier, more vibrant plant. It can also help with weed control and disease resistance.

Moreover, fertilizing early will give your grass and plants the best start, so they won’t need much more down the line. A phosphorus- and nitrogen-based starter fertilizer will give seedlings the energy and nutrients they need. It’s key for healthy growth right off the bat and lets them absorb soil nutrients more effectively, saving you multiple applications.

What is the best fertilizer to start grass? 

The best starter fertilizer for grass will depend on your grass type and soil. Generally, a fertilizer with an NPK ratio (nitrogen, phosphorus, and potassium) of 10-10-10 or 20-10-10 is recommended.

Still, it’s best to check with your local Cooperative Extension Office in advance for soil testing and recommendations on fertilizers suited for your lawn. 

Popular starter fertilizers for grass include:

Scotts Turf Builder Starter Fertilizer for New Grass – 24-25-4
The Andersons Premium New Lawn Starter – 20-27-5 
The Andersons PGF Balanced 10-10-10 Fertilizer
Jonathan Green & Sons, 11543 Green Up 12-18-8, Seeding & Sodding Lawn Fertilizer
Lesco Premium 18-24-12 Starter Fertilizer

Find more of the best options on the market in our review of the best lawn fertilizers

Can you apply starter fertilizer to established grass?

While it is technically possible, applying starter fertilizer to an established lawn is not recommended. Starter fertilizer is designed for the special needs of young plants and may not contain all of the nutrients that an established lawn needs for continued growth and health. It is best to use a well-balanced fertilizer for established grass.

How do you apply starter fertilizer?

The best way to apply fertilizer in most cases also extends to starter fertilizer. It should be applied evenly across the soil surface. For optimal performance, it is best to follow the manufacturer’s instructions, with considerations for soil type, grass type, and application technique. 

Here are the basic steps for fertilizing new grass with starter fertilizer: 

• Test your soil prior to application. 
• Prepare the area for seeding or sod by dethatching, aerating, and tilling the soil.
• Choose a starter fertilizer with a suitable NPK ratio and apply it evenly over the area before seeding or laying the sod. You can use a fertilizer spreader for larger areas.
• Work the fertilizer into loose soil to help ensure even distribution.
• Once the seeds or sod are in place, lightly water the area to help the nutrients sink in. 
• Wait about two months before applying a regular lawn fertilizer.

Final Thoughts 

With the right mix of nutrients, a starter fertilizer can give your grass and plants the kick-start they need for lush green foliage. Whether dealing with a lawn or other plants, testing and evaluating your soil beforehand is essential. That way, you get a good understanding of your soil’s needs and can mix up the right ratio of NPK for your plants.

Plus, starter fertilizer helps your plants make the most of their nutrients, so you don’t have to keep applying fertilizers frequently – saving you time and money in the future. Don’t have the time or know what to do? Get help from the pros! Find a lawn care specialist near you and get expert advice on starter fertilizer and any other lawn care needs you may have.

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Luminita Toma

Luminita Toma is a nature-loving writer who simply adores pretty flowers and lawns. After plenty of research and writing on lawn care and gardening, she's got a keen eye for plants and their maintenance. When she's got some spare time, there's nothing she enjoys more than chilling with her friends, hitting the theatre, or traveling.