Fertilizer Dilution Calculator
Mix liquid plant food with confidence. Enter your fertilizer's NPK values and desired strength to get the exact amount per gallon of water.
Calculate Your Mix
Enter your fertilizer values and click Calculate.
How Fertilizer Dilution Works
Understanding NPK Ratios
NPK stands for Nitrogen (N), Phosphorus (P), and Potassium (K). The three numbers on your fertilizer bottle represent the percentage by weight of each nutrient. A 10-10-10 fertilizer contains 10% of each.
Parts Per Million (ppm)
Most liquid feeding recommendations use ppm of nitrogen. For houseplants, 100–200 ppm N is a safe range. The calculator converts your fertilizer's nitrogen percentage into the exact milliliters or teaspoons needed per gallon.
Avoid Root Burn
Over-fertilizing pulls water out of plant roots through osmosis, causing brown tips and wilting. Always measure precisely—never guess with concentrated fertilizers.
Quick Reference: NPK Needs by Plant Type
Different plants need different nutrient balances. Use this guide to choose the right fertilizer and target ppm.
| Plant Type | Ideal NPK | Target N ppm | Frequency |
|---|---|---|---|
| Leafy Houseplants (Pothos, Philodendron) | 10-10-10 or 20-20-20 | 125–175 | Every 2 weeks |
| Flowering Plants (Orchids, African Violets) | 10-30-20 | 100–150 | Weekly during bloom |
| Succulents & Cacti | 5-10-10 | 50–100 | Monthly |
| Vegetable Gardens | 10-10-10 or 5-10-10 | 150–200 | Weekly |
| Lawns (Cool Season) | 20-5-10 | 200–300 | Every 4–6 weeks |
Tip: When in doubt, start with half the recommended strength. You can always add more, but you cannot undo fertilizer burn.