CX Hydroponics One Part Grow and One Part Bloom Ultimate Soil Nutrients. Use for vigorous growth and heavy flowers in any potting soil. Ultimate for Potting Soil is so versatile that it can be used in all climates and all areas and in all soil mixes. Ultimate Soil nutrient is very robust and able to cope with the varying pH, salinity, nutrient levels, drainage, nitrogen drawdown, water holding capacity and air filled porosity of any standard potting mix. May also be used for plants grown in garden situations outdoors.