Potassium Sulphate (Sulphate of Potash / SOP) Water Soluble Fertiliser | K 42% S 18%

Potassium Sulphate (Sulphate of Potash, SOP) Water Soluble Fertiliser

Bigger, denser, better quality flowers and fruit start with potassium. Potassium sulphate, also called sulphate of potash or SOP, is the premium potassium source for growers who care about quality. It supplies a heavy dose of potassium plus plant-available sulphur, with minimal chloride, so it is safe for sensitive crops where cheaper muriate of potash (potassium chloride) is not.

Guaranteed analysis

Contains no nitrogen (N) or phosphorus (P), which makes it ideal for pushing potassium in flowering and fruiting without adding unwanted nitrogen.

What it does for your plants

• Flower and fruit quality: potassium moves sugars and starches through the plant, which means larger, heavier, sweeter and better coloured fruit and flowers.
• Water regulation and stress tolerance: potassium controls how leaf pores open and close, helping plants cope with heat, drought and cold.
• Stronger plants: it activates the enzymes behind protein and starch production, building sturdier stems and better disease resistance.
• Sulphur for flavour and aroma: sulphur is essential for protein and chlorophyll production and plays a role in the compounds that give crops their flavour and smell.
• Minimal chloride: the right choice for chloride sensitive crops such as berries, grapes, potatoes, tobacco, leafy greens and cannabis.

Signs your plants need potassium

• Yellowing, browning or a scorched look along the edges and tips of older leaves
• Weak stems and slow growth
• Small, poorly coloured or poorly filled fruit and flowers

How to use

Dissolve fully in water before use and always measure EC. For reference, every 1 gram per litre of water adds 420 ppm potassium and 180 ppm sulphur, and 0.25 g per litre adds about 105 ppm potassium and 45 ppm sulphur. Adjust your dose to your crop, growth stage and base nutrient.

• Tip: potassium sulphate dissolves more slowly than most other fertiliser salts. Use lukewarm water and stir well until the solution is clear.
• Hydroponics and coco: add to your reservoir, then adjust pH.
• Soil, pots and garden beds: dissolve and drench, or work into the soil and water in well.
• Works with Hydroflow: Hydroflow Hydroponic Nutrient is designed to be used together with potassium sulphate when extra potassium is needed.

Important mixing rule

Never mix potassium sulphate in concentrated form with calcium products such as calcium nitrate or calcium magnesium nitrate. The sulphate reacts with calcium and drops out of solution as a solid. In a two tank system it goes in Tank B, away from the calcium. Once diluted in your final reservoir it is perfectly fine to combine.

Pack sizes

• 1kg: ideal for home growers, tents and small systems.
• 25kg bag: best value for commercial growers, greenhouses, orchards and hydroponic farms.

Store sealed in a cool, dry place. Packaging may vary.

Pairs well with: Hydroflow Hydroponic Nutrient, Calcium Nitrate, MKP, Epsom Salts and Calcium Magnesium Nitrate.