🌿 Lawn Fertilizer Calculator
Calculate how much fertilizer your lawn needs based on area, grass condition, and NPK type.
Lawn Details
m²
-
-
Seasonal Guide
| Season | N (Nitrogen) | P (Phosphorus) | K (Potassium) | Advice |
|---|---|---|---|---|
| Spring | High | Medium | Medium | Encourage leafy growth after dormancy |
| Summer | Balanced | Low | Medium | Slow-release to avoid burn in heat |
| Autumn | Low | Medium | High | Strengthen roots for winter hardiness |
| Winter | None | None | None | Avoid — grass is dormant, fertilizer wasted |
Application Tips
| Tip | Details |
|---|---|
| Water before & after | Water lawn 24–48h before application; water in within 24h |
| Use a spreader | Rotary or drop spreader ensures even coverage; avoid hand spreading |
| Avoid wet grass | Apply to dry grass to prevent burning; granules clump on wet blades |
| Split applications | For large doses split into 2–3 sessions 4–6 weeks apart |
| Edge areas | Apply around edges first, then fill in the middle in overlapping passes |
| Store correctly | Keep unused fertilizer in a sealed, dry container away from moisture |
Understanding NPK Ratios
N (Nitrogen) promotes leafy, green growth. High-nitrogen fertilizers are best in spring when grass is actively growing.
P (Phosphorus) supports root development and is important for establishing new lawns or recovering bare patches.
K (Potassium) improves disease resistance and winter hardiness. Raise K in autumn to prepare grass for cold months.
Over-fertilizing warning: Applying more than 6g of nitrogen per m² risks chemical burn, turning grass yellow or brown. Always err on the lower end and apply more frequently rather than in one heavy dose.