Fertilizer bags usually show numbers like 15-15-15 or 20-10-10. These numbers represent the NPK content, which are the three key nutrients plants need most.
NPK (Nitrogen-Phosphorus-Potassium ratio) stands for:
N = Nitrogen (1st number)
- Encourages strong leaf and stem growth
- Very important for leafy crops like maize and vegetables
- Too much nitrogen can cause excessive leaf growth but weak fruiting
P = Phosphorus (2nd number)
- Supports root development and early plant strength
- Promotes flowering and seed formation
- Low phosphorus leads to weak roots and slow crop maturity
K = Potassium (3rd number)
- Improves plant strength and disease resistance
- Enhances fruit quality, size, and drought tolerance
- Deficiency results in weak plants and reduced yields
Example: 15-15-15
- A balanced fertilizer
- Suitable for general crop growth
Example: 20-10-10
- Higher nitrogen content
- Best for leafy crops or early growth stages
Key point
The NPK numbers represent percentages of nutrients in the fertilizer, not the total weight. For example, in a 50kg bag of 20-10-10:
- 20% is nitrogen
- 10% is phosphorus
- 10% is potassium