NPK Fertilizers For Plants – A Complete Guide

Are you searching for NPK fertilizers for your garden plants? Look no further and save your time! 

If you prefer inorganic NPK fertilizers, there are plenty of options available in your local market. Likewise, if you prefer organic NPK fertilizers, you can find them in your home and surroundings.

Choose one carefully before applying it to your garden, and your plants will be happy.

The significance of NPK fertilizers lies in their composition. These special fertilizers contain essential macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). Applying these fertilizers in the right amounts promotes healthy plant growth and prevents any nutrient imbalances in the soil.

Don’t worry! Take your time and read this complete article on NPK fertilizers for plants in your small home garden. It will address all your doubts.

Here is your comprehensive guide on NPK fertilizers for your garden.


Why Are NPK Fertilizers Important For Your Plants? 

I will give you a brief idea of how plants obtain nutrients and their reliance on photosynthesis for energy production. Just like animals, plants also require various macronutrients and micronutrients to support their growth and overall health.

Macronutrients, which are required in larger quantities, include carbon (obtained from carbon dioxide), hydrogen (from water), and oxygen (from both carbon dioxide and water). 

These elements are the building blocks for carbohydrates, fats, and proteins in plants. Through photosynthesis, plants convert these basic elements into glucose, which serves as their primary source of energy.

In addition to macronutrients, plants also need various micronutrients for specific physiological functions. 

These micronutrients include elements such as nitrogen(N), phosphorus(P), potassium(K), calcium, magnesium, and several others. 

Read also:  Goat Manure Fertilizer Can Boost Your Plant Growth - Complete Guide
NPK Fertilizers


They play critical roles in processes like cell division, enzyme activity, photosynthesis, and the overall growth and development of plants.

Deficiencies or imbalances in these essential nutrients can have detrimental effects on plant growth. 

For example, nitrogen deficiency can lead to stunted growth and yellowing leaves, while a lack of phosphorus can hinder flower and fruit production. 

Plants obtain these nutrients from the soil or other growth media they are planted in, and their availability can be influenced by factors like soil pH, organic matter content, and microbial activity.

To ensure optimal plant growth, it’s important to provide a well-balanced nutrient supply. 

This can be achieved through the use of fertilizers that contain the necessary macronutrients and micronutrients. 

Additionally, maintaining a healthy soil environment, proper watering, and adequate sunlight are all important factors in supporting nutrient uptake and utilization by plants.

Understanding the nutritional needs of plants and providing them with the required elements in appropriate quantities is key to promoting their growth, productivity, and overall vitality.

Plants need fifteen Basic Elements from the soil. Those nutrients can be categorized into Three Categories viz. Macronutrients, Secondary Nutrients, and Micronutrients.  


Functions & Deficiency Symptoms Of Plant Nutrients:

Nutrients Category Basic ElementsFunctions Deficiency Symptoms
MacronutrientsNitrogenNitrogen helps the plants to make the special protein that helps in the overall growth of the plant as well as strengthens the roots.The plants that have been drying. The color of the leaves take light green.
PhosphorusDuring photosynthesis (the process of preparation of food in the presence of sunlight), plants form ATP which is the energy unit of the plant. Phosphorus is a vital component of ATP and deficiency of Phosphorus hampers the growth of the plants.The color of the leaves takes dark green color. Fruiting and vegetative growth become delayed and production becomes less than normal.
Potassium involves the movement of water, nutrients, and food to the different plant tissue. Its deficiency will hamper the movement process and growth of the plant will be stopped.Spotted leaves.
Secondary NutrientsCalciumImproves root formation and increases the resistance to seedling disease.Young leaves of terminal buds become drying.
MagnesiumAids chlorophyll formation and potassium metabolism.Creating dead spots.
SulfurEnhance the dark green color of the plants. The color of the leaves becomes pale green.
MicronutrientsZincWorks as a stimulator for the secretion of essential plant hormones Auxins and other enzymes.Young leaves become yellowish or even white and veins become green.
ChlorineWater transportation.Water will not reach every part of the plant smoothly.
BoronHelps in glucose transfer and cell divisions.Young leaves of terminal buds become light green.
MolybdenumHelps in nitrogen fixation and nitrogen assimilation.Plants become light green.
CopperWorks as an enzyme and helps in light reactions.Young leaves permanently become drying.
IronImproves the process of chlorophyll formation.Inter-venial tissue becomes yellowish and veins become green.
ManganeseSpeed up germination and maturation.Inter-venial tissue becomes yellowish and veins become green.
CobaltCrucial for nitrogen fixation.Plants become light green and will suffer from chlorosis.
NickelHelps in the viability of the seed.Hamper the seedling process.

Source: United States Department of Agriculture

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How Should You Apply NPK Fertilizers In Your Garden?

Plants get all the required nutrients from the soil. Each type of soil has its own components. Some soils may lack certain nutrients. Using fertilizer can help reload those nutrients and make the soil suitable for farming.

How Will You Understand The Condition Of Your Garden Soil? 

To understand your soil better, you can perform a soil test. There are various soil test kits available in the market that you can buy for your home garden.

It’s recommended to perform the soil test every five years unless you’ve made significant organic changes to improve the soil structure since the last test.

The main soil test includes the soil pH level test and npk presence level test. Let’s get detailed knowledge about these. 

Soil pH test:

> Soil pH level refers to the acidity or alkalinity of a  particular soil. It is directly related to the availability of different nutrients in the soil.

> Soil pH level of 7.0 means neutral.  The pH level of below 7.0 refers to the soil as acidic and the pH level of above 7.0 refers to the soil as alkaline. 

> 6.5 is the preferable soil pH level for growing vegetables. In case of soil pH level below 5.5 or above 7.5, soil modification and amendment are required.   

NPK Fertilizers


How To Modify Soil Ph Levels As Needed By Your Plants?

How is it possible?Precautions
Raising soil pH levelYou can apply lime to the soil with a pH level below 5.5
Common lime materials suitable for adding to the garden are crushed limestone, dolomite, burned lime, quick lime, hydrated lime, etc. 
> Don’t use excess lime in the soil. Over-application may cause iron chlorosis.
> Follow the exact application procedure.
> Lime takes 1 to 3 years to increase the soil pH level.
Lowering soil pH levelYou can apply elemental sulfur to the soil with a pH level above 7.5
Elemental sulfur is available in the market and commonly used compound.
> This procedure is costly and hence, is not feasible for large areas. But it can be done for the garden areas.
> Sulfur reacts slowly with the soil and takes 1 to 3 years to get the best result.
> It needs to be applied every year. To determine the particular time of application, test the soil periodically. 


Best (Most Favorable) Soil Ph Level For Different Vegetable Plants:

Name of the vegetables in your home gardenBest soil pH level
Beet6-8
Cabbage6-8
Peas6-7.5
Spinach6-7.5
Carrots6-7
Cucumber5.5-7
Lettuce6-7
Pumpkins5.5-7.5
Tomatoes5.5-7.5
Potatoes5-6.5


How Much NPK Fertilizers Should You Apply In Your Garden?

The rate of application of fertilizer in the soil depends on the nutrient analysis of the fertilizer and amount of fertilizer needed to be applied in the soil.

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While applying NPK fertilizers in the soil, you can follow the below-mentioned formula and can determine the exact amount needed for the application of the fertilizer.

FormulaDescription
Pounds of fertilizer to apply to your gardenAmount of fertilizer in pounds/ 1000 sq. ft = nutrient needed in pounds/ 1000 sq. ft.(percent of nutrient in fertilizer/100)Suppose 1 lb nitrogen is required to apply per 1000 sq. ft of your garden area and the NPK ratio of your fertilizer is 10-20-10.
Then you have to apply 10 lbs fertilizer to add 1 lb nitrogen to your garden soil.
The application of 10 lbs of fertilizer will add 2 lbs of phosphorus and 1 lb of potassium to your garden soil.
Side dress nutrient application rateSide dress nutrient application rate in pounds/ 1000 sq. ft.= total nutrient needed – pre-plant nutrient application rate – (organic matterX0.4)
* if the result is 0 or negative, don’t apply side-dress nutrients.
> Preplant: Application of fertilizer before planting.
> Side dressing: Application of fertilizer at the time of growing plants.
Application of fertilizer if weight scale is un-availableVolume of material to apply= pounds of material to apply / (total pounds of material in container/ total volume of material in container)

Ref: Source link


What Is NPK Number?

N-P-K numbers will help you understand the percentage of  Nitrogen(N), Phosphorus(P), and Potassium(K) available in the fertilizer.

The numbers on a fertilizer label represent the percentage of each element in the product, in the order of N-P-K. 

For example, a 10-10-10 fertilizer contains 10% nitrogen, 10% phosphorus, and 10% potassium.


What Are The Methods Of Applying NPK Fertilizer In Your Garden?

There are various fertilizer application methods that a gardener should know before applying fertilizer to the plants of the garden. These methods are detailed below:

Name of the methodsDescription 
Top dressing Application of nitrogenous fertilizers in closely sown crops like paddy and wheat to supply nitrogen to the soil.
Side DressingApplication of fertilizer in between rows (in the case of crops like maize) and around the plants (in the case of trees like mango, apple, grapes, papaya, etc.). 
BroadcastingIt is the method of application of fertilizer uniformly in the soil. 
This method is beneficial when your garden soil is acidic and highly nutrient (nitrogen and potassium) deficient. 
FertigationIt is the application method where fertilizer is applied to the plant with irrigation water. 
Nitrogen is the main nutrient to be applied to the soil in this method.
It is a relatively cost-saving method. 
FoliarMethod of application of liquid fertilizer. You have to spray liquid fertilizer on the foliage of growing plants. 
It is effective at the time of application of micronutrients. 
You should take care about the concentration of fertilizer in the solution, otherwise, it will hamper the growth of the plants in your garden. 
PlacementInsert the fertilizer below the soil surface using any tools. This method can be used either before sowing the seeds or to the standing crops. 

You can get detailed knowledge about the fertilizer application by checking out this link


Inorganic & Organic NPK Fertilizer – An Overview:

The npk fertilizer can be broadly categorized as inorganic npk fertilizer and organic npk fertilizer. 

Inorganic NPK fertilizer

A list of some widely used inorganic npk fertilizers is given below:

Name of the fertilizersCharacteristics of the fertilizers
Diammonium Phosphate (DAP)> The N-P-K ratio is 18-46-0.
> The initial application increases the soil pH rate. Subsequently, after a long period, the soil becomes more acidic due to the nitrification of ammonia. 
Ammonium Sulphate> The N-P-K ratio is 21-0-0.
> The most suitable fertilizer for alkaline soil.
> It lowers soil pH levels and adds nitrogen for plant growth. 
Potassium Sulphate> The N-P-K ratio is 0-0-50.
> Used as fertilizer to add potash to the soil of the garden.
Ammonium Nitrate> The N-P-K ratio is 34-0-0.
> Adds nitrogen to the soil of your kitchen garden.
Potassium Nitrate> The N-P-K ratio is 13-0-44.
> Adds nitrogen and potassium to the soil of your kitchen garden.
Potassium Chloride> The N-P-K ratio is 0-0-62.
> Adds potassium and chlorine to the soil of the kitchen garden.
> It is a less costly option among inorganic fertilizers.
Ammonium Dihydrogen phosphate> The N-P-K ratio is 12-61-0.
> It supplies nitrogen and phosphorus to the soil.
Calcium Nitrate> The N-P-K ratio is 15.5-0-0 + 19% calcium.
> Adds nitrogen and calcium to the soil.
> It is very popular for use in greenhouse and hydroponic systems of farming. 
Phosphate> It is an inorganic fertilizer rich in phosphorus. 
> It helps in plant growth.
Ammonia> It is a rich source of nitrogen.
> The application of ammonia helps in the flowering and fruiting of the plants in your kitchen garden. 
Sodium Nitrate> The N-P-K ratio is 15-0-2.
> It adds nitrogen and sodium to the soil of your garden.> Avoid applying it to the foliage of the plant because the excess application may burn the plants. 
Ammonium Phosphate> The N-P-K ratio is 18-46-0.
> Rich in nitrogen and phosphorus.
> It helps in the overall growth of the plants including better flowering and fruiting.

Organic NPK fertilizers

If you want to get strict to maintain an organic home garden, you have to choose organic fertilizers also for supplementing nutrients to the soil of your home garden. 

There are a lot of organic fertilizers also available for use in the soil of your home garden. If you want to get detailed knowledge about organic npk fertilizers, please click on the below link. 

[Organic N-P-K Fertilizers]


How To Choose The Right NPK Fertilizer For Your Garden?

Choosing the right NPK fertilizer is crucial for your plant’s health and growth. 

Here are some of the key factors to consider:

Using Correct NPK Numbers: 

As said earlier, Nitrogen (N), Phosphorus (P), and Potassium (K)  are the three primary macronutrients required by plants.

You have to choose the suitable fertilizer after analyzing the N-P-K Numbers in that particular fertilizer.

Consider Secondary and Micronutrients: 

In addition to the NPK ratio, consider the presence of secondary nutrients (such as calcium, magnesium, and sulfur) and micronutrients (such as iron, zinc, and manganese) in the fertilizer. These nutrients are also essential for healthy plant growth. 

If your soil test reveals deficiencies in particular secondary nutrient(s), choose a fertilizer that includes that particular nutrient(s) in higher amounts.

Fertilizer Formulations: 

Fertilizers come in different formulations as discussed earlier. Consider the convenience, application method, and specific requirements of your plants when selecting the formulation. 

Slow-release fertilizers release nutrients gradually over time, providing a longer-lasting supply.

Type of plants: 

Different plants have varying nutrient requirements. Determine whether you are growing leafy greens, flowering plants, or fruiting plants. This will help you identify the specific nutrient needs of your plants.

Soil type:

Understand the soil composition in your garden. Is it sandy, loamy, or clayey? 

Each soil type has different nutrient-holding capacities and may require specific fertilizer formulations to address any deficiencies.

Desired result: 

Consider your gardening goals. Are you aiming for robust foliage, vibrant blooms, or abundant fruits? 

This will guide you in selecting the appropriate NPK ratio to promote the desired outcome.

Organic vs. Synthetic Fertilizers:

Decide whether you prefer organic or synthetic fertilizers. 

Organic fertilizers are derived from natural sources and provide a slow release of nutrients. They improve soil health and microbial activity. 

Synthetic fertilizers, on the other hand, are manufactured and provide a rapid nutrient supply. They are often more concentrated but lack the soil-building benefits of organic fertilizers.

Follow Package Instructions: 

Read and follow the manufacturer’s instructions regarding the application rate and frequency. 

Over-fertilizing can damage plants and the environment, while under-fertilizing may result in nutrient deficiencies.

By taking these factors into account, you can make an informed decision when choosing the right NPK fertilizer for your garden. Remember, providing the correct balance of nutrients is essential for healthy plant growth and optimal yields.

NPK Fertilizers overview - infographics


Advantages & Disadvantages Of N-P-K Fertilizer

Sl. No.AdvantagesSl No. Disadvantages
tTThe application of organic npk manure adds minerals and nutrients to the soil organically. It improves the condition of the soil by increasing fertility, water-holding capacity, and improving the drainage system.1.Organic npk manure releases its nutrients slowly. It takes more time compared to other inorganic compounds. Sometimes, it takes more than one year or an entire growth cycle of a particular plant to supply nutrients after its application.
2.Organic npk compounds contain low or moderate levels of nutrients. Therefore, its application to the soil becomes much handier,2.As it contains moderate levels of nutrients, it requires a large amount for application to get the best benefit of the manure.
3.Organic npk manures are environment-friendly. It reduces the greenhouse gas effect and prevents soil erosion and water pollution.3.Most organic npk manures can’t be used without composting. At the time of composting, it may create some bad odor that may attract flies and insects.
4.Adding organic npk manure to the soil increases microbial activities resulting in improved bio-diversity.4.The result of the application of organic npk manure becomes sometimes inconsistent. The result depends on the type of plants, climatic conditions, and soil quality.
5.If you can arrange the organic npk manure at your home, it is a cost-effective way to fertilize your soil5.If you can’t arrange it at home, the availability of organic npk manure except for the kitchen scraps may be somehow difficult.


Conclusion and Take Away!

By now you have got all the information(What? Why? When? How?) that you need to understand the usefulness of N-P-K fertilizers.

So what are you waiting for? Bookmark this page for future use and share it with friends who are really into gardening.

I hope I’ve addressed all your concerns about N-P-K fertilizers. If you’re curious about other cool farming methods or the best veggies and herbs for your home garden, check out my other articles in the related post section below or the recent post section at the top-right.

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