What is 18-24-12 Fertilizer Good For? A Complete Guide

As a gardener, these numbers on the fertilizer bag are pretty significant, right?

If you want a healthy garden, your soil must have the right balance of nutrients. That’s where the 18-24-12 fertilizer comes into action.

But what exactly does this number show? This number indicates the NPK ratio.

So, the fertilizer contains:

  • Nitrogen (N): 18%
  • Phosphorus (P): 24%
  • Potassium (K): 12%

Well, what makes up the rest of the bag?

It depends.

Some fertilizers contain other micronutrients, such as magnesium or calcium. Other additional ingredients include fillers.

Now that you understand this fertilizer label, it is time to talk about NPK.

What Does 18-24-12 Mean?

To understand what this fertilizer is good for, you must know what it provides.

Nitrogen (18%):

Nitrogen is the go-to nutrient for powering any leaf, stem, and foliage growth.

This is why we say nitrogen is involved in forming healthy and robust foliage, essential functions like photosynthesis, and the growth of flowers.

You must understand that 18% nitrogen in fertilizer is pretty high. This can be great for dealing with nitrogen deficiency that can slow the growth of your plants.

What is 18-24-12 Fertilizer Good For?

But things are a bit different sometimes. That’s why I say that nitrogen is a tricky macronutrient.

In the case of overfertilization, too much nitrogen will do more harm than good.

This is because plants will focus too much on their leaves instead of flowering or fruiting.

Let me summarise all this for you.

Nitrogen is the go-to nutrient for healthy, robust foliage and essential functions like photosynthesis.

Now, let’s jump to phosphorus.

Phosphorus (24%):

Recall the role of nitrogen. It powered plant growth.

When it comes to phosphorus, it powers fruiting and blooms.

So if you want to increase hydrangea blooms or you want more tomatoes from your vegetable plant, this high-phosphorus fertilizer will do the job.

The other primary function of phosphorus is supporting plants’ shoot and root systems. Thanks to phosphorus that our plants anchor firmly in the soil.

The comparatively high phosphorus content than nitrogen and potassium makes this fertilizer special for some plants.

That’s what we will be covering later in this article.

Phosphorus powers blooms and fruiting. The right amount of phosphorus means an improved root system, beautiful flowers, and healthy fruits.

Potassium (12%):

This member of the “Big Three” regulates the function of enzymes and controls the flow of liquids.

Potassium’s ability to increase plants’ resistance to diseases makes it essential for plants. This, in turn, will make your plants strong and vibrant.

The best part?

Potassium is the key to conserving moisture, leading to increased drought resistance. Therefore, potassium deficiency will make your plants vulnerable to diseases.

That’s not what we want.

This “Big Three” member increases plants’ resistance to diseases. It improves the plant’s overall health by making them strong and vibrant.

What is 18-24-12 Fertilizer Good For?

This fertilizer is great for phosphorus-loving plants.

The high phosphorus in the 18-24-12 fertilizer is great for fruit trees (early growth), heavy-feeding tomatoes, carrots, and bulbs. Phosphorus is the go-to nutrient that powers blooms and fruiting. The right amount of phosphorus means an improved root system, beautiful flowers, and healthy fruits.

Let’s take a look at some of them.

Plants That Like 18-24-12 Fertilizer:

Plants That Like 18-24-12 Fertilizer

Fruit Trees:

Generally, fruit trees need high phosphorus to grow and develop.

This phosphorus is vital during early growth and when trees flower.

Plus, the 18-24-12 provides a good overall ratio of nutrients, which is the key to healthy fruit trees.

This NPK ratio works great on my 5-year-old fruit tree, which blooms yearly, producing more fruit each year.

But, a soil test is an excellent investment to know your soil condition and to get personalized recommendations.

But without a soil test, 18-24-12 is a good choice.

This takes us straight to our next point.


Tomatoes are generally heavy-feeding plants and need plenty of nutrients to grow and develop.

The high phosphorus in 18-24-12 supports fruit development.

Since these are heavy feeders, they should be fertilized throughout the growing season.

However, in case of plenty of nutrients in your soil, switch to a lighter blend, such as 5-5-5 or 10-10-10.


Carrots generally need a balanced fertilizer. This means that all three macronutrients (NPK) are essential.

The part of the carrot we consume is the root of the plant.

You got the point.

We know that roots need a lot of phosphorus to grow and develop. As 18-32-12 is high in phosphorus, it will work perfectly for carrots.

The phosphorus will support the vegetable, leading to healthy growth.

Nitrogen and potassium in this fertilizer are vital for the plant’s health.


You must use different fertilizers at different stages of their growth cycle to get the best output.

When planting, the 18-24-12 (high phosphorus fertilizer) boosts initial growth and supports root growth.

For other stages, a lighter and balanced blend, such as the 10-10-10, is mainly recommended for bulbs.

Remember that potassium is essential for healthy blooms and to deal with environmental stress.

You May Like:

What is 20-20-20 fertilizer good for?

8-32-16 fertilizer for tomatoes | Is It The Best?

Plants That Don’t Like 18-24-12 Fertilizer:

Plants That Don't Like 18-24-12 Fertilizer

Acid Loving Plants:

Acid-loving plants like phosphorus.

But, too much phosphorus than other macronutrients can lead to nutrient imbalance.

That’s not what we want.

This excess phosphorus can bind to other elements like calcium in alkaline soils.

The other problem is that too much phosphorus in the soil increases its pH, which is the opposite of what we need.

Therefore, it is best to go with a fertilizer specially designed for acid plants should be used.

Leafy Vegetables:

I want you to recall the role of nitrogen.

It is the go-to nutrient for healthy, robust foliage and essential functions like photosynthesis.

You should know that leafy vegetables love more nitrogen. In most cases, they perform well with a balanced fertilizer.

However, high phosphorus in the soil, as discussed above, leads to phosphorus toxicity.

This means the plant excessively absorbs phosphorus and reduces the intake of other essential nutrients.

A balance between nutrients is what makes leafy vegetables grow and develop.


Now let’s jump straight to the next plant.


Grevilleas originate from Australia and grow in Australia’s low phosphorus soils.

The high amount of phosphorus is not the best choice.

Can you recall why this is so?

As we discussed earlier, this NPK ratio can lead to a nutrient imbalance that can affect flowering.

Plants that don't like 18-24-12 fertilizer

As they are not heavy feeders, it is best not to overfertilize. For best results, use a slow-release fertilizer specially formulated for them.


How To Apply 18-24-12 Fertilizer:

When it comes to Fertilizer, you have two options:

Granular or Liquid.

Let’s take a look at each of them in detail.


Granular fertilizers are slow-releasing and release nutrients gradually.

Apply the Fertilizer in a circular pattern around the plant’s root zone. Then, water it in so that the Fertilizer starts working.

In the case of lawns, sprinkle it using a fertilizer spreader according to the package instructions.

The best part?

As the nutrients are released gradually, the chance of burning is low.

This takes us straight to our next point!


The application process of a liquid fertilizer is very simple.

Find out how much fertilizer to apply from the back of the package.

Then, mix it accordingly. Apply it near the plant’s root zone using water can.

The best part?

As liquid fertilizers are water soluble, their nutrients are instantaneously available to the plant for uptake.


FAQ’S About 18-24-12 Fertilizer:

Now, let me address some common questions about 18-24-12 Fertilizers.

What is high phosphorus fertilizer good for?

Phosphorus in the soil supports the development of roots that encourages the flowering and fruiting of the plant.

So if you want to increase blooms or want more tomatoes from your vegetable plant, a high phosphorus fertilizer will do the job.

Overusing phosphorus has disadvantages and should be applied according to the plant’s needs.

You can find out your plant nutrient needs with a simple soil test.

Is 18-24-12 Fertilizer Good For Lawns?

Yes and No.

It depends. What works for me may not work for you.

Therefore, the best thing you can do is to conduct a soil test. This blend can do wonders if your soil is low in all three macronutrients.

There are different 18-24-12 fertilizers specially formulated for lawns.

This fertilizer helps develop newer lawns and maintains old grass.

18-24-12 is an excellent choice for lawns as it provides all the essential nutrients in a significant quantity.

Nitrogen is the key to a greener and more vibrant lawn, and phosphorous improves the overall root system.

Recommended Product:

The Andersons 18-24-12, after testing many products, proved to perform the best on my lawn.

After using it for a couple of months, it transformed my dull, patchy lawn into a lush dark green one.

This fertilizer works best on any lawn if you carefully read the instructions on the package and apply it accordingly.

Final Verdict:

Due to high phosphorus, whether to use the 18-24-12 fertilizer is a common question.

So from all this discussion, we can say that this NPK ratio is great if you want more blooms.

So, what is 18-24-12 fertilizer good for?

Plants like tomatoes, carrots, and bulbs love this fertilizer as it generates better blooms and greener leaves for them.

If you have more questions, feel free to get in touch. Stay tuned for more.

Happy Gardening!

You May Like:

What is 12-4-8 Fertilizer Good For? All You Need To Know

What is 18-24-12 Fertilizer Good For? A Complete Guide

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top