The 18-18-18 fertilizer has an even distribution of the three primary plant nutrients: nitrogen, phosphorus, and potassium, each nutrient is allocated at 18%. This fertilizer is recommended for general purposes such as lawns, vegetables, growing flowers, trees, and shrubs.
It provides a good source of nutrients for the plants and helps to keep the pH levels balanced. This fertilizer can be used on both indoor and outdoor plants.
18-18-18 fertilizer's component
As the source of agricultural chemistry, the plant mainly takes the essential nutrient to revive their biochemical function and manage the cell nutrients by the way of providing these essential nutrients.
Of them, the three most important essential nutrient is Nitrogen which refers mainly (to N), Phosphorus (p2o5), and Potassium (K2O). All these fertilizer has the structural mechanism and ion exchange capability which plants parts can easily uptake and give a positive effect on the plants.
Besides these three nutrients, this fertilizer also provides additional essential nutrients such as magnesium, sulfur, and calcium which are in different fertilizer products with the combination of these three primary nutrients.
It's generally applied in the spring as growth begins or when nutrient deficiencies are first noticed.
The chemical composition may be as like:
Fertilizer | Fertilizer |
---|---|
Total nitrogen (N)18 % | Phosphorus pentoxide (P205)18 % |
- Nitric nitrogen (NO3)9.7 % | |
- Ammoniacal nitrogen (NH4)8.3 % | Potassium oxide (K2O)18 % |
For extension use of foliage PGR formula, these nutrients also are added with the related ratio of the fertilizer:
- Magnesium oxide
- Sulfur trioxide
- Iron
- Manganese
- Zinc
- Copper
- Boron
- Molybdenum
Why is The 18% percentage NPK important for plants?
As an agriculturist, it's really as simple as that, but for those who want to understand, it is the perfect ratio for the general growth of a plant. If you want your plants to grow quickly, you need more nitrogen.
If you want really strong roots and disease resistance then you need more phosphorus and if you want your plant to produce fruit or flowers then you need more potassium. The 18-18-18 fertilizer provides the best possible solution to keep up the growth and health of your plants.
Best implementation of 18-18-18 fertilizer.
Most often when you're a beginner grower or hardly knowledgeable about fertilizer management, you must keep in mind that, exceeding fertilizer can hamper the growth of your plants as well as may cause wilting, infestation, or further fruit formation.
As per the usage of the NPK of 18% fertilizer, let's know where you can use this formula widely.
Lawn Care:
One of the top fertilizers for lawn care is the 18-18-18 fertilizer, it is a perfect lawn fertilizer that can be used for newly seeded lawns as well as for established ones.
The best way to use 18-18-18 fertilizer on your lawn is to apply it before you seed or in the winter season.
This will give the grass a chance to absorb the nutrients and grow quickly. You can also use it during the summer to keep your lawn healthy and green.
Growing flowers:
When the flowers start their growth, they need more phosphorus than nitrogen to produce a good bloom. For the 18-18-18 fertilizer, it will be suitable for this case as all three nutrients are in balanced form.
In general, when you use the fertilizer there is always a recommended rate written on the label of the fertilizer. You need to follow that strictly.
Vegetables:
As we all know, vegetables are the major source of human food and it is important to have a good yield from them.
For this, you need to use the fertilizer in such a way that it will help the plant to grow faster and also give a good yield.
Most vegetables like tomato, brinjal, chili, etc. are heavy feeders and they need more nitrogen for their growth. At the stage of the foliar condition, the fertilizer management can be different as per the requirements of plant growth.
The gardener passionate about their gardening techniques and improving the yield variation must be concerned that the 18-18-18 ration of fertilizer is a great option to go with easily.

Fruit formation:
For fruit production, potassium is more essential than the other two nutrients. So, the 18% of K content in this situation will greatly impart, and for any foliar production, this nutrient will eventually keep the fruit formation and its maturity level up without having issues of pest infestation or other problems.
Most gardeners have fruit trees like mango, orange, jackfruit, grape, citrus, etc. in their garden area goes for this option to have a bumper crop every season.
Ornamental tree:
Now as a horticultural assessment program, I have faced a lots of problems belonging with fertilizer management as an ornamental tree.
If you're passionate about ornamental trees like Amelanchier, Japanese maple, etc. then this fertilizer is the best to go with as it will help the tree to grow faster and also give it a good shape to it.
Furthermore, if you have any dedicated trees which have other nutrient requirements then the case will be different. But as usual, most ornamental shrubs, or trees need a balanced ration of these three nutrients.
How to use 18-18-18 fertilizer?
The 18-18-18 fertilizer may have different forms as per the requirement of the plant. It can be liquid, granular, or powdery. If you need to spray the fertilizer, then you need to go with the liquid form of it.
For granularity, you can apply it around the plant or tree as per the specified dosage by fertilizer spreader. And the powdery form is to be mixed with water and then can be used for spraying or pouring around the plant.
It's always necessary to follow the dosage as per the plant's requirement.
- Most Foliar use: 100-400 Gram Per 80-100L water.
- The Granuler use: 2-4 Kg Gram per Decare
Definite plants:
For general case lawns | For Citrus and other fruit trees | For vegetable plants |
---|---|---|
4 to 5 grams per square meter | 100 to 200 grams per tree. ( can be changed the dose according to size) | As foliar or granular use. |
How often should you use 18-18-18 fertilizer on lawns?
The terms of how often should the 18 18 18 fertilizer used depends on the various factor like usage, land type, land area, etc. As it is slow release type fertilizer, then this fertilizer can be used every 3 to 6 months.
But if the condition of your garden is poor, then you need to use it every month until the condition improves.
In general, a healthy lawn will require mostly 1 time in a year around. But as per the condition, you can use it 2 times or thrice a year.
I would suggest keeping an eye on the lawn grass and looking if the grass looks deficiency symptoms, it must reconsider using a definite amount of fertilizer again.
Conclusion:
As per the article, it is clear that the 18-18-18 fertilizer is a great option to go with as it has a balanced amount of nutrients that are essential for plant growth.
If you have a wide range of plants from lawn to vegetables and other ornamentals, then this fertilizer is the best option as it will be easy to manage.
It is always necessary to use the fertilizer as per the dosage and specified frequency to achieve better results.

I am a graduate of Bangladesh Agricultural University, where I delved into various agricultural disciplines, equipping me with a profound understanding of agriculture. Beyond academics, I have hands-on experience in gardening and crop cultivation. My passion is to embrace sustainable farming and horticulture. With a BSc in Agriculture, I am dedicated to promoting environmentally conscious and efficient agrarian practices.
Bachelor of Science (BSc) in Agriculture (Hons.)
Master of Science. (Sustainable Agriculture & Food Security ) (MS)
Bangladesh Agricultural University