Calculate exactly how much fertilizer your garden needs
🧮 Fertilizer Amount Calculator
📚 Understanding NPK Numbers
NPK stands for Nitrogen (N), Phosphorus (P), and Potassium (K) – the three essential nutrients plants need.
Promotes lush, green foliage and overall plant growth. Essential for leafy vegetables and lawns.
Best for: Lettuce, spinach, kale, lawns, herbs
Supports strong root systems, flower formation, and fruit production. Critical for blooming and fruiting.
Best for: Tomatoes, peppers, flowering plants, root vegetables
Strengthens plant immunity, improves drought tolerance, and enhances fruit quality and flavor.
Best for: Fruiting vegetables, stressed plants, disease-prone areas
Recommended NPK Ratios by Plant Type
| Plant Type | Recommended NPK | Why |
|---|---|---|
| Leafy Greens | 20-10-10 or 3-1-2 | High nitrogen for leaf production |
| Tomatoes/Peppers | 5-10-10 or 1-2-2 | Lower nitrogen, higher P & K for fruiting |
| Root Vegetables | 5-10-10 or 2-3-3 | Phosphorus for root development |
| Flowering Plants | 15-30-15 or 1-2-1 | High phosphorus for blooms |
| Herbs | 5-5-5 or organic compost | Low feeding needs, balanced growth |
| Lawns | 20-5-10 or 4-1-2 | High nitrogen for dense green growth |
💡 Fertilizing Tips & Best Practices
⏰ Timing Matters
Best time: Apply in morning or evening when temperatures are cooler. Never fertilize during midday heat.
Season: Feed most heavily during active growing season (spring-summer).
💧 Water Before & After
Water plants 24 hours before fertilizing to prevent root burn. Water again immediately after applying granular fertilizer to activate nutrients.
📏 Less is More
Over-fertilizing causes more problems than under-fertilizing. Start with half the recommended amount and increase if needed.
🌱 Young vs Mature
Seedlings: Use 1/4 strength liquid fertilizer
Young plants: 1/2 strength
Mature: Full strength
🍂 Fall Feeding
Stop nitrogen fertilizer 6-8 weeks before first frost. Late feeding promotes tender growth that’s damaged by cold.
🧪 Soil Test First
Test soil every 2-3 years. You may already have adequate nutrients! Testing prevents waste and over-application.
- Brown, crispy leaf tips and edges
- White crust on soil surface (salt buildup)
- Wilting despite adequate water
- Yellowing lower leaves
- Stunted growth or leggy plants