Potassium nitrate

Potassium nitrate is produced by combining a potassium salt with a nitrate source, yielding a crystalline compound with roughly 44–46% potassium (as K₂O) and about 13% nitrogen, entirely in nitrate form. Its guaranteed analysis is commonly expressed as 13-0-45.

Chemical formula

KNO₃

Potassium content

About 44–46% K₂O, no chloride carrier

Nitrogen content

About 13% total nitrogen, entirely as nitrate

Solubility

Fully soluble in water; suited to solution and fertigation systems

Potassium nitrate supplies potassium, an essential macronutrient for osmotic regulation, water relations, and enzyme activation, together with nitrate-nitrogen, which is immediately available for root uptake without the hydrolysis or nitrification steps required by amide or ammonium sources.

• Potassium is supplied without an accompanying chloride ion
• Nitrogen is delivered entirely as nitrate, taken up rapidly by roots
• Contains no phosphorus or micronutrients

Potassium nitrate is widely used in fertigation and hydroponic nutrient solutions because of its complete solubility and low risk of clogging drip systems, and on crops such as potato, tomato, and banana where chloride sensitivity or fruit quality considerations disfavour chloride-containing potassium sources.

• Well suited to drip fertigation and soluble nutrient-solution programs
• Preferred on chloride-sensitive crops and in saline-prone growing areas
• Also used as a foliar-applied potassium and nitrogen source in some systems

Potassium nitrate is commonly split into multiple applications through the growing season, either via fertigation or as periodic soil or foliar treatments, to match crop potassium and nitrogen demand while limiting any single high-concentration dose.

The nitrate fraction of potassium nitrate is mobile in soil and subject to the same leaching and denitrification pathways as other nitrate-based nitrogen fertilizers, particularly under high rainfall, over-irrigation, or coarse-textured soils.