How Often to Fertilize Lawn for Best Results - Lawn Chick (2024)

Every homeowner wants their lawn to be green and lush all year long. With a good understanding of fertilizer, that dream lawn can be within your reach. Fertilizer gives your lawn the additional nutrients it needs to stay green and healthy. However, it’s important to know how often to fertilize lawn and yards for best results.

This article was last updated on by Lawn Chick Owner Sarah Jameson
Article content reviewed for accuracy by Certified Horticulturist Nicole Forsyth, M.S.

Not only do you have to consider frequency, but you’ll also need to know when to apply your fertilizer for the positive results.

Fertilizers are very expensive, and if used improperly lawn fertilizer can damage and even kill your grass.

A little bit of knowledge makes all the difference in keeping your budget in check and your lawn lush.

In this article I’ll share how often to fertilize your lawn for best results, and provide tips to save money and reach your lawn goals.

And if you’d like a free, done-for-you lawn care schedule – grab my cheat sheet while you’re here. In it you’ll get a detailed schedule for a full season of lawn care.

How Do You Know How Often to Fertilize Lawns?

There are several important factors that come into play when you’re trying to understand lawn fertilization frequency. These include:

• Lawn fertilizer application times
• The type of fertilizer you use
• How you apply your fertilizer
• How frequently you water your lawn

I’ll discuss each of these points in some detail below.

Understanding When to Apply Fertilizer

I recommend fertilizing your lawn four times annually with an organic, slow-release lawn fertilizer.

Nicole Forsyth, a certified horticulturist and member of our expert panel, recommends that you plan your applications around holidays so it’s easy to remember when to feed your lawn. “The holidays to apply lawn fertilizer are: Easter, Memorial Day, July 4th, Labor Day, Halloween, and Thanksgiving,” she says.

The exact holidays you choose will depend upon your local climate (more on that in a moment), but if you choose four of those that fall at the right time of year, you’ll have a pretty good schedule for fertilization.

Your First Application of Fertilizer

Your first application of fertilizer is best applied early in the season when grass has just started to grow.

This gives your grass a boost of nutrients early to help it take root and green up very quickly. When applied with a good pre-emergent herbicide (I use Espoma’s corn gluten meal, which is organic), you allow your lawn to crowd out annual weeds every single year and you won’t need as many weed killer products for your lawn.

The rule of thumb is to apply your first batch of fertilizer when your soil hits 55-degrees Fahrenheit.

Usually, you can tell when the soil reaches temperature when lilacs bloom and grasses begin to sprout.

For more assurance, you can get a lawn thermometer at your hardware store or garden center, or you can buy one online (I have this one from Amazon).

After Your First Lawn Fertilizer Application

So now you know about the first treatment, but are wondering how often to fertilize lawn areas throughout the rest of the year?

After your first application, you want to apply another round of fertilizer 6 to 8 weeks later and repeat that two more times with 6 to 8 weeks in between.

Try to schedule your applications so you apply ahead of the hottest part of summer to give your lawn the necessary boost.

For an established lawn, you’ll fertilize 4 times each season, though that is based on some important assumptions. If your grass is damaged and you’re growing it fresh, your lawn will require more treatments until it’s established.

This is also true if your lawn has a species of grass that isn’t native to your climate, like in areas that are more hostile to grasses. Alternatively, the opposite is also true. Fertilizing regularly is most necessary when trying to keep alive grasses that aren’t native to your area.

It’s very likely you can get away with only fertilizing 1 to 2 times per year if the grass in your lawn is native. A healthy lawn can get by with fertilizing in the spring, and maybe again In the fall to keep it strong through the off-season.

Apply Your Fertilizer When Grass is Growing

No matter how frequently you fertilize your lawn, the rule of thumb you should follow is that you should apply fertilizer while your grass is growing the fastest.

Over applying fertilizer runs a big risk to your yard:

• It’s bad for the environment, since runoff pollutes local streams.
• It runs the risk of “burning” your grass, which is when you sap grass of natural nutrients causing it to brown.
• Lastly, you’re wasting money by buying too much fertilizer.

By applying fertilizer when your grass is growing, you’re supporting the natural growth cycle of your grass (be it cool season grasses or warm season grasses), and you’re not taxing the grass and asking it to grow too much when it needs to be in survival mode and develop strong roots to sustain itself.

What Type of Fertilizer to Choose for Your Lawn

There are several varieties of fertilizer to choose from. The biggest variable is organic versus synthetic fertilizer.

That said, you’ll also hear fertilizer described as either quick-release or slow-release, but there’s significant overlap between the two.

Organic fertilizers are natural and come from plant or animal sources.

Synthetic fertilizers are derived of components made in a lab.

Organic fertilizers are primarily slow release. In practical terms, slow-release fertilizers help develop your soil to grow your grass strong using its own capacities. Synthetic fertilizers are more potent, and they help your grass green up faster, but they don’t help your soil.

In my experience, relying too much on synthetic fertilizers can weaken the soil so much your grass can’t sustain itself without applications of synthetic fertilizer.

For me, that’s a problem.

It’s not sustainable, and it’s why I use organic, slow release fertilizers on my lawn.

That said, synthetic fertilizers have almost immediate results. If you want your grass green quick, it’s the option to go with, and I do recommend a quick-release starter fertilizer when starting a lawn from seed.

If you want long-term sustainability for your existing lawn, an organic slow release is a better choice, and my recommendation.

There’s also the option to apply a synthetic fertilizer as your first application, then apply organic fertilizer to strengthen your yard later in the season.

Understanding What’s In Your Lawn Fertilizer

When choosing a fertilizer, you’ll need a basic understanding of the fertilizer’s NPK rating.

NPK rating is the fertilizers levels of:

• Nitrogen,
• Phosphorous, and
• Potassium (which is “K” on the periodic table).

For a standard lawn, a good choice for your first application of the season is around a 20-5-10 NPK rating.

That means the fertilizer is comprised of 20% nitrogen, 5% phosphorous, and 10% potassium. Those three are the primary nutrients for grass, similar to how people need a proper balance of macro nutrients (protein, fat, and carbohydrates) to thrive.

• Nitrogen makes your lawn grow and green quickly, and it’s essential throughout the season.
• Phosphorous promotes healthy root development. That’s why it’s recommended to apply high phosphorous fertilizers early in the season to help your grass develop strong roots early. If you water regularly and well, your lawn’s roots will be able to withstand drought and dryness in the hottest part of summer. However, Phosphorous in high concentrations is bad for the environment, so more places are regulating the allowed amounts or banning it altogether.
• Potassium promotes overall grass growth for a healthy, balanced lawn.

Synthetic fertilizers are more potent and have higher NPK ratings, while organic fertilizers have lower ratings.

The higher potency of synthetic fertilizers is why they have more immediate results in making your grass green. However, that’s also why they are unsustainable.

Synthetic fertilizers inhibit your lawn’s ability to fend for itself, since the fertilizer replaces its natural processes.

Slow release, organic fertilizers take longer to show results, but their results last longer and are better in the long run.

How to Apply Fertilizer to Your Lawn

Lawn fertilizers are sold in either liquid or granulated form.

This is mostly important in determining how to spread the fertilizer. With organic fertilizers, the difference comes down to what the fertilizer is comprised of. Corn grain meal based fertilizers are typically granular, while fish emulsions are liquid.

Synthetic fertilizers are available in both forms.

Speaking generally, most homeowners find granular fertilizers easier to apply.

If you want to use a liquid fertilizer, it is simpler to hire a professional service like TruGreen or a local alternative to do so.

It’s more difficult to measure out and ensure even application of a liquid fertilizer. Professional services do that regularly and understand how to apply it.

Using a spreader to apply granular fertilizer is a simple process. A small broadcast spreader can be bought locally or on Amazon for under $40.

Using a spreader is easy – fill the hopper up on pavement, then walk the spreader across your yard.

Start with the perimeter, using an edge-guard to keep the material in your grass. Then go line by line until your yard is covered.

Spread it at a lower than recommended rate at first. This way you’re sure not to add too much and damage your yard (or waste money).

Make sure to sweep any granules off the pavement and into your yard. Left on pavement, they can harm the environment if allowed to wash into storm drains.

Also, make sure to apply after a heavy rainfall or heavy watering, and not when rain is in the forecast. You don’t want the rain to wash away your hard work and money.

Watering Your Lawn After Fertilizer Application

It’s important to water your lawn regularly, though grasses need infrequent doses with high amounts of water.

Your fertilizer will specify whether you need to water before or after application. Typically, granular fertilizers require light watering after application to adhere the granules to the turf.

Make sure not to over water, though, because you’ll wash away nutrients before your grass can absorb them.

Maintaining Your Lawn

Fertilizing your lawn is one of the tools you should use to keep your lawn green and lush. You should use it alongside regular mowing and watering.

A healthier lawn will also require less maintenance, and you can get away with less fertilizing. If you mulch your grass clippings and leave them on your yard, they’ll provide nitrogen into your soil and strengthen your grass.

Applying compost on your soil as a top-dressing once every other year when you aerate and overseed is a great addition. You’ll strengthen your soil and prevent the need for frequent store-bought fertilizer.

Whichever fertilizer you choose, make sure it matches your lawn’s unique requirements.

Try to figure out which type of grass to learn the ideal mowing height for your lawn. Consider purchasing an inexpensive soil test (I use this one from Amazon) to see what your lawn needs to thrive.

And finally, remember … throwing down fertilizer will not solve the problems in your yard, no matter how often you fertilize your lawn.

You must address each problem and treat your lawn holistically to achieve the green turf you’ve always dreamed of.

Please explore my blog to find other articles to help you get the results you are after.