This table is a general guideline. There is a wide range of values in the ADEQUATE column but, for younger plants, we recommend that you keep nutrient levels at the lower end of the adequate range. To amend your potting mixture, see our Calculation Forms.
| PARAMETER | UNIT | LOW | ADEQUATE | HIGH |
|---|---|---|---|---|
| pH (less than 20% soil) | <5.5 | 5.5-6.8 | >6.8 | |
| pH (more than 20% soil) | <6.0 | 6.0-7.0 | >7.0 | |
| EC (Conductivity) for mature plants | ms/cm | <0.7 | 0.7-3.5 | >3.5 |
| EC (Conductivity) for young plants | ms/cm | <0.5 | 0.5-2.0 | >2.0 |
| Available Nitrogen (ammonia + nitrate) | ppm | <40 | 40-200 | >200 |
| Phosphorus (less than 20% soil) | ppm | <5 | 5-25 | >25 |
| Phosphorus (more than 20% soil) | ppm | <2 | 2-18 | >18 |
| Potassium | ppm | <50 | 50-150 | >150 |
| Calcium | ppm | <50 | 50-200 | >200 |
| Magnesium | ppm | <20 | 20-150 | >150 |
| Sodium | ppm | 0-80 | >80 | |
| Sulfur | ppm | <20 | 20-200 | >200 |
| Boron | ppm | <0.5 | 0.5-2.0 | >2.0 |
| Iron | ppm | <10 | 10-40 | >40 |
| Manganese | ppm | <5 | 5-30 | >30 |
| Zinc | ppm | <5 | 5-30 | >30 |
| Copper | ppm | <0.5 | 0.5-10 | >10 |