Potassium Alum (potassium-aluminum sulphate) is applied to lower the pH value of the soil in order to color hydrangeas blue. This product contains the right dose of aluminum for the blue color. The potassium also ensures firmer leaves.

Dosage of Potassium Alum

The dosage of Potassium Alum is 20-100 grams. This of course depends on the size of the plant or pot. Always consult the label for dosages or contact the fertilizer specialist in the crop care department.

Application of Potassium Alum

The blue coloration of hydrangeas can be enhanced by the use of Potassium Alum. Apply this annually, between early and mid-September, by sprinkling it around the plant and raking it in, or dissolving it well in warm water and pouring it close to the plant. Prevent the Potassium Alum from touching the leaves.

Packaging Potassium Alum　

Potassium Alum is delivered in bags of 20 kg.