This table is a general guideline. Values may change with different plant types and growth stages. There is a wide range of values in the ADEQUATE column but, for younger plants, or to slow the growth rate, we recommend that you keep nutrient levels at the lower end of the adequate range. To amend your potting mixture, see Calculation Page.
PARAMETER | UNIT | LOW | ADEQUATE | HIGH |
---|---|---|---|---|
pH (less than 20% soil) | <5.0 | 5.0-6.8 | >6.8 | |
pH (more than 20% soil) | <5.5 | 5.5-7.0 | >7.0 | |
Conductivity (mature plants) | mmho/cm | <0.7 | 0.7-3.5 | >3.5 |
Conductivity (young plants) | mmho/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 |