Types of Lawn Fertilizers – How to Choose the Right One


Do you dream of having the perfect lawn?

Most homeowners do nothing more than cut the grass when it gets too high, but for others, it’s a dedicated mission to achieve a beautiful patch of green space to be proud of.

And it’s just as challenging as it is rewarding.

Of the many steps required, choosing between all the types of lawn fertilizers can be a daunting prospect.

In this article, we help to sort through all the fertilizer products available, so you know exactly what to use on your lawn.

Plus, there’s some extra advice on how and when to apply it, as well as plenty of general tips and tricks for boosting lawn health.

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What Type of Fertilizer to Use? Too Long, Didn’t Read

Let’s get right to the point – for anyone who doesn’t have time to skim through the whole article.

Lawn fertilizers aren’t as confusing as you might think, and can be divided into the following general types:

  • Granular
  • Liquid

Then, they can be subdivided into these types:

  • Organic
  • Synthetic

They might also be described as :

  • Spring fertilizer
  • Fall fertilizer
  • After winter products

Finally, they can include a pre- / post-emergent weed killer as part of a weed and feed-type product, or they can be a dedicated lawn fertilizer on their own.

That’s it, in a nutshell, but there’s a lot more to it than that – including an explanation of the nutrients contained within each fertilizer, when to use it, how much to put down, and the dangers of overuse.

And, of course, how to choose the right one in the first place!

hand with granual fertilizer over plant

For all this and more, stay with us, and read on!

Do You Need Lawn Fertilizer?

It’s a great question – surely your lawn grass can grow on its own, so why do you need fertilizer in the first place?

Technically, you don’t. You can just let nature do its thing, and you’ll have an average patch of grass in your yard that does its job of looking like an average patch of grass.

But if you want to wow your guests and the BBQ, then you need to take action.

Last year, when overseeding, I applied fertilizer on my front lawn, and nothing on the lawn at the back – as a simple experiment.

You would have been amazed at the difference in the quality, health, and color between the two.

My rear lawn was its regular, old, average self, and my front lawn was thick, carpet-like, and a vibrant shade of green.

And it’s not hard to see why.

While the soil provides some nutrients that growing grass requires – it’s not able to provide everything a lawn needs to really be the best it can be.

This is especially true during the growing season, and/or when you’re planting new seed.

New grass in particular needs as much help as possible to germinate, and grow into a lush, healthy lawn, as it takes a lot of energy to do so.

That’s where the right choice of lawn fertilizer comes in. You don’t need it, but boy is it going to make a visibly noticeable difference.

person using fertilizer

And that’s not to mention the benefits a lawn fertilizer can give you for keeping pests, weeds, and disease away.

Types of Fertilizer for Grass

When shopping for lawn fertilizer, you might be overwhelmed at the sheer number of products vying for your cold hard cash, and it can be intimidating if you’re totally new to lawn care.

How to know what fertilizer to use on your lawn?

We can start by breaking down the different types, which we can do like this:

Lawn fertilizer is available in either granular or liquid form. Below, you’ll find a more detailed explanation of the two and how they are applied.

From there, a fertilizer will either be an organic or synthetic product.

Organic Fertilizers

As the name suggests, is an all-natural fertilizer that is designed to break down in the soil and release nutrients to aid plant health and growth. Follow this link for some top organic gardening tips.

It usually consists of things like seaweed, blood meal, manure, fish bones and scales, and compost. They can help boost micronutrients in the soil, although they do have a lower “NPK” rating.

Keep reading for a full explanation of the NPK numbers.

If you have the time and the materials, it’s possible to make organic fertilizers at home – and there are plenty of recipes available on the internet.

It’s a good idea if you have access to a compost bin, and you can follow that link to find some excellent tumblers. You’re literally throwing money away if you’re not composting!

Synthetic Fertilizers

Synthetic fertilizers are man-made products designed to give your garden the best possible chance at health. They’re water-soluble, fast-acting, and used when you need to see more rapid results.

These fertilizers contain inorganic compounds and by-products, such as ammonium nitrate, ammonium phosphate, and potassium sulfate.

Synthetic fertilizers are cheaper than organic fertilizers, but they don’t contain any “micronutrients,” such as iron, zinc, magnesium, and sulfur.

A plant actually needs a total of 17 nutrients to thrive – not just the “NPK” that are more prominent in synthetic fertilizers.

This article on synthetic vs organic fertilizers has more information, but both certainly have their place when it comes to lawn care.

In general, however, I would choose a synthetic fertilizer for fast results, and an organic option for a long-term, slow-release feed and sustenance.

person in yellow gloves holding granual fertilizer

NPK Numbers Explained

You might have noticed a set of three numbers somewhere on the lawn fertilizer packaging, with (or often without) the abbreviation NPK.

Here we come to the dreaded sciency-bit. But fear not, for we here to bust the jargon, as checking a fertilizer’s nutrient content is an important part in the selection process.

NPK refers to the chemical symbols for nitrogen (N), phosphorus (P), and potassium (K), and the numbers tell you how much of each nutrient is included in that particular fertilizer.

For example, if the packaging or specifications read 10-20-10, then you have a fertilizer with 10% nitrogen, 20% phosphate, and 10% potassium.

The rest of the fertilizer will be made up of filler (which is why these numbers don’t add up to 100%).

Simple, right?

Of these, nitrogen is the most important, essential to the development and health of plants (and just about anything that lives). It helps build proteins and DNA in living organisms.

Plants that are starved of nitrogen will be visibly affected, and show signs of stunted growth, yellow/brown leaves, and appear to be withered and dry.

It could be one of the reasons your grass is discolored, and this article on fixing yellow grass might be able to help.

Phosphorus is considered second only to nitrogen when it comes to plant health, and it helps to promote photosynthesis – the plant’s ability to use sunlight to synthesize foods from carbon dioxide and water.

This, in turn, affects how a plant stores and uses energy. Without it, a plant will be weak, brittle, and show signs of discoloration – similar to blue/purple/red bruising.

Fruit, seeds, and flowers will also be deficient.

Finally, potassium is important in the general movement of nutrients, water, and carbohydrates through the organism.

It helps the plant to grow, resist drought, combat pests and disease, and provide a healthy yield of fruits and vegetables where relevant.

In a lawn, potash (as it’s often known) encourages deep roots and healthy green stems.

A potassium-deficient plant will show curled, yellow leaves, roots will not be strong and extensive, and yields will be low and of poor quality. The plant will be more vulnerable to pests and disease.

So, now you know what each mineral element does, how do you know how much of each your grass actually needs?

Different regions have different lawns. And different lawns require different amounts of nutrients – depending on what is and what isn’t already present in your soil.

To keep things simple, here’s a rough guide to choosing the right balance of lawn fertilizer nutrients:

For a damaged or stressed lawn – look for a fertilizer that’s high in nitrogen and potassium, which can help give the grass the boost it needs to get stronger.

For a healthy existing lawn – a nitrogen-rich lawn fertilizer is the way to go, easing off on the P and K numbers.

For starting a new lawn – this is where phosphorus and potassiumnitrogen come into their own, in order to establish a strong root system. Keep the nitrogenpotassium to a minimum until the new life has had a chance to settle in.

person fertilizing lawn with liquid fertilizer

And this article on when to fertilize new grass for the best possible results should help you if you’re taking the first steps in your quest for a backyard putting green.

However, if you’re genuinely serious about choosing the right type of fertilizer for your lawn, you can’t rely on a general, catch-all guide.

Therefore, it’s essential that you know and understand the type of soil you have in your yard and garden before purchasing a lawn fertilizer – as well as the species of grass.

You might be able to ask a neighbor, do some research on the internet, or even make an educated guess.

But a dedicated soil test is the only way to be 100% sure.

Soil Testing and Grass Type

Oh, how we wish we’d paid more attention in biology class! But before you start freaking about conducting science experiments in your backyard, let us put your minds at ease.

Soil testing is as easy as purchasing a soil testing kit, and following the simple instructions – depending on the type of kit you’ve selected.

When the results are in – which can be in minutes or a few days – depending on the type of test you use – you will have a better understanding of what your soil already has, and what it lacks.

You can then choose an appropriate fertilizer that can redress any imbalance. Furthermore, if you also intend on growing fruit or vegetables in your garden, then a soil test is essential to use in your plots.

As well as testing the soil, you should also pay attention to the type of grass you have in your yard – and identify if you have warm or cool-season grasses.

Warm-season grasses, such as St Augustine, Bermuda, and centipede, will need more treatment than cool-season grasses like Kentucky bluegrass, tall fescue, and rye.

How and When Lawn Fertilizers Are Applied

Liquid fertilizers are dispensed by either using a tank or backpack sprayer, or, more commonly for large areas, hooking a spray bottle up to a garden hose. Try using a hose cart with wheels to make things easier.

Granular fertilizers will be distributed using a walk-behind broadcast spreader – or by hand. Just make sure for both practices you’re wearing a pair of good-quality gardening gloves.

Alternatively, if you have the means (and the lawn size) a granular fertilizer is best dispensed from one of these awesome tow-behind spreaders.

Liquid fertilizers typically offer faster results than granular, designed to be quickly absorbed into the plant or soil to stimulate the green and the growth.

Granular fertilizers are more suitable for greater control over your lawn-care schedule, as they offer residual time-release formulas that prevent nutrients from washing away.

For a more detailed article on the liquid vs granular fertilizer debate, follow that link.

But when should lawn fertilizer be applied?

granual lawn fertilizer

When it comes to lawns, it depends on the type of grass you have, and where you are on your current lawn care schedule.

The fall and spring are the best times, when the grass is growing, and you’ve already cut it a few times. This article on lawn care after winter, and this one on fall lawn care will tell you more.

Go here for more general information on how often you need to fertilize your garden, and this article offers a complete, month-by-month guide to lawn care.

But before we move on, here’s a pro-tip – when it comes to choosing season-specific lawn fertilizer – give them all a miss and save money.

Simply choose one, good-quality fertilizer that’s right for your type of soil and grass, and use it throughout each fertilizing season.

Remember, the vast majority of these “sensational” new lawn-care products are just clever marketing ploys. You don’t need a “fall” fertilizer, any more than you need a “spring” one.

However, I would choose a starter fertilizer if you’re specifically trying to establish new grass.

Over Fertilizing a Lawn

With all these nutrients packed into a lawn fertilizer, can’t you just dump bag after bag on your lawn for the best grass in the universe?

Unfortunately, no. When it comes to this type of product, you can have too much of a good thing.

Excess lawn fertilizer can “burn,” your grass. That’s to say, it won’t set it alight, but it will seriously raise the nitrogen and salt levels, which will turn your grass yellow and/or brown, eventually killing it off completely.

As such, it’s important you stick to the distribution guide of the particular fertilizer you’re using, and you resist the temptation to apply too much “feed” in the hope that more is going to mean more.

Soil Amendments

Soil amendments are not strictly classed as fertilizers, as they are designed to improve the quality of the soil itself, and not directly boost nutrient levels to the plant.

Otherwise known as soil conditioners, they help with the physical properties of the soil, and improve its overall fertility for plant life to grow.

This includes improved water and nutrient retention, permeability (which makes it easy to break down), and drainage.

Weed and Feed Fertilizers – Yes or No?

Finally, we should take a look at one of the most popular types of lawn fertilizer on the market – the hybrid weed and feeds, often manufactured by familiar household names.

These products are designed to stimulate grass growth and lay down either a pre-emergent or post-emergent herbicide at the same time. It is an extremely convenient two-birds-one-stone option.

But are they actually any good?

Yes and no is the short answer.

Some gardeners swear by them, as they’re supposed to save time and money.

However, others have seen less than favorable results in achieving the desired effects – which is frequently the case when using two-in-one products that aren’t dedicated to one purpose.

Check out this article on if fertilizer actually kills weeds, or if you need to find another method with a better chance of success.

crabgrass in lawn

Alternatively, if you do have a weed problem, you might like to try to tackle weeds in your lawn without the use of chemicals, and you can follow that link for tips on how to do so.

FAQs

Does fertilizer go bad?

It’s a great question. You’ve spent a small fortune on lawn fertilizers, and for one reason or another, you’ve got a stack of it left. Can you use it again next season?

This article on fertilizer shelf life will tell you everything you need to know.

What tools do I need for lawn care?

Glad you asked! Aside from lawn-care products like fertilizers, if you’re going to strive for a beautiful lawn, you need to have a well-stocked tool shed.

This article offers an essential lawn-care tool guide for all the gear and equipment you need – as well as the stuff you don’t. Head on over to find out if you’re missing something crucial.

What is the best fertilizer for lawns?

If you’re still having a bit of trouble making the choice, watch the in-depth video below:

Summary

Now you understand the different types of lawn fertilizers, you should be in a better position to choose the one that is right for your garden.

Let us know in the comments which option you’ve gone for, or if you have any lawn fertilizing stories and experiences you’d like to share with other lawn-loving green thumbs.

Stay safe out there, and we wish you the very best of luck with your lawn!

Andy Gibson

My name's Gibson. Andy Gibson. I like to think of myself as the Bond of the backyard, that is if yard work ever became sexy. I write about everything about indoor and outdoor gardening and the dread-it-but-still-need-to-do-it chores around the yard, like cleaning out the gutter guards.

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