The NPK ratio is used to indicate the concentration and ratio of plant nutrients contained in a fertiliser. The three letters—N, P, and K—represent the three main plant nutrients using their elemental sign from the periodic table. The three main plant nutrients are nitrogen (N), phosphorus (P), and potassium (K). For a plant to grow and thrive, these three main nutrients—also called essential macronutrients—must be available in large quantities.
NPK Ratio: The Nutrients and their Role in Plant Development
While all plants require nitrogen (N), phosphorus (P), and potassium (K), the amount each plant needs will vary depending on its species. Fruit trees, for example, are heavy feeders and need plenty of potassium and nitrogen to produce high-quality fruits. By comparison, blueberries are used to arid conditions and can produce fruit without much extra fertilisation.
The three essential macronutrients are known to each cause particular effects on the plant, each playing its own distinct role in the plant’s development. Nitrogen is responsible for the growth of shoots and leaves. Phosphorous encourages root growth and flowering. Potassium transports energy around the plant and is needed during the blooming period.
Not only do different species of plants require different amounts of N, P, and K, but a plant’s needs also change over the course of the growing season. At the start of the season, nitrogen will be more important because plants are putting all their energy into developing thick foliage and strong stems. Later, when the blooming period begins plants require more phosphorus and potassium. The NPK ratio can be used to select the appropriate fertiliser for the period of the growth cycle, as well as the type of plant you are attempting to grow.
NPK Ratio Numbers
Since the nutritional needs of a plant differ between species and over the course of the growing season there are many different types of NPK fertiliser.
The key nutritional difference between fertilisers is represented by the NPK ratio which is stated as three numbers, where each number corresponds to a nutrient. A fertiliser with an NPK ratio of 10-10-10 has equal parts nitrogen (N), phosphorus (P), and potassium (K).
The number in the ratio also indicates the concentration of the fertiliser. An NPK ratio of 20-20-20 means it contains equal parts nitrogen, phosphorus, and potassium each at a concentration of 20% of the total mix.
It is also possible to find fertilisers where one or two of the NPK ratio numbers are zero, which means one or two of the three macronutrients have been excluded from the formula. This means the fertiliser is dedicated to a particular purpose. An NPK ratio of 20-0-0 would mean the fertiliser only contains nitrogen and can be used to resolve nitrogen deficiencies or encourage strong leaf development.
NPK Fertilisers from BAC
If you’re looking for a high-quality NPK fertiliser to stimulate growth or support your plants through the blooming period, then here at BAC we have several options for you to consider:
Organic Grow: Our Organic Grow formula has an NPK ratio of 7-2-3, which makes it ideal for the early phase of plant development.
Organic Bloom: With a reasonably balanced NPK ratio of 6-5-6, Organic Bloom is a great fertiliser for the flowering period.
Soil Grow Nutrients: Perfect for the growth phase, our Soil Grow Nutrient mix has an NPK ratio of 7-1-4.
Soil Bloom Nutrients: Although less concentrated than our Organic Bloom mix, our Soil Bloom Nutrient formula will ensure an abundant blooming period with an NPK ratio of 6-1-4.
F1 Extreme Booster: A extremely concentrated mix of phosphorus and potassium, our F1 Extreme Booster has an NPK ratio of 0-13-14.