Dense Bud Compactor Potassium is needed in relatively large amounts to support the various plant functions critical for huge yields. Potassium is vital in the activation of more than 80 plant enzymes that regulate various functions including the opening and closing of the stoma necessary for proper gas exchange and water usage. Potassium is also very important in the utilization and conversion of Phosphorous into an energy source. Application Rates • Soiless or Coco fiber 1-2 grams per litre / 4-8 grams per gallon • Hydroponic use 1 gram per litre / 4 grams per gallon of nutrient solution