Potting Media Parameters

Potting Media Parameters

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

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