Potassium Thiosulphate Fertilizer Uses

Potassium Thiosulphate (K₂S₂O₃) is a clear liquid fertilizer that supplies potassium (K₂O) together with sulphur in the thiosulphate form, applied as a foliar spray or through drip fertigation. Under India's Fertilizer (Control) Order 1985 (FCO), the specified grade must contain at least 25% water-soluble potassium (as K₂O) and at least 17% sulphur (as S) by weight. Fertilizers fall under the FCO, not the Insecticides Act — so unlike the crop-protection technicals on this site, this page is not CIB-registered content. PAU (Punjab Agricultural University) and ICAR have not published crop-specific application rates for this exact product, so the dose guidance below follows the product's own FCO-label recommendations, as noted under the table. This page lists its role in plant nutrition, key benefits and recommended application.

Which Growth Stage Is This For?

Being potassium-rich with added sulphur and no nitrogen or phosphorus, this fertilizer is generally matched to the flowering, fruit-set and fruit-filling stages, when the crop's demand for potassium is highest — not to the early vegetative stage. The table below maps common crop groups to the growth stage it is typically used at.

Mode of Action / Nutrient Role

Potassium thiosulphate supplies potassium and sulphur in fully water-soluble, liquid form, allowing quick uptake through the leaves or the root zone under fertigation. Potassium regulates stomatal opening and water movement in the plant, activates enzymes involved in sugar transport and starch formation, and strengthens the plant's tolerance to heat, drought, pests and disease — which is why it improves fruit size, sweetness, colour and firmness. The thiosulphate form of sulphur is gradually converted in the plant and soil into plant-available sulphate; sulphur is needed to build certain amino acids and proteins, chlorophyll, and the oils and flavour compounds in oilseeds, onion, garlic and many vegetables.

Features & Benefits

• Supplies two nutrients — potassium (K₂O 25% min.) and sulphur (S 17% min.) as per FCO specification — in one liquid product.
• Clear liquid that mixes easily in water; suitable for foliar spray and drip fertigation.
• Nitrogen-free and phosphorus-free, so it can be used at flowering and fruiting stages without pushing excess leafy growth.
• Helps improve fruit size, sugar content, colour, firmness and shelf life.

Recommended Usage of Potassium Thiosulphate Fertilizer

The table below gives the foliar-spray concentration and number of sprays per crop group. At a typical spray volume of 200 litres of water per acre, 2 ml/L works out to about 400 ml of product per acre per spray, and 2.5 ml/L to about 500 ml per acre per spray.

The rates above follow the product's own FCO-label guidance, because PAU and ICAR have not published crop-specific application rates for potassium thiosulphate. The per-acre quantities assume a spray volume of 200 litres of water per acre; for fruit trees the total quantity depends on tree size and spray volume. Always confirm the current label of your specific product and consult your local Krishi Vigyan Kendra (KVK) before finalising a spray schedule.

How to Use

1. Identify your crop's growth stage — this fertilizer is generally used from flowering through fruit filling, not at early vegetative growth.
2. Fill the spray tank half-full with clean water, add the measured quantity of product, and top up to the full volume while stirring.
3. Spray uniformly on both sides of the leaves with a knapsack or power sprayer, preferably in the early morning or late evening.
4. For drip fertigation, inject the product into the fertigation tank as per your drip system's schedule, and flush the lines with clean water afterwards.
5. Repeat sprays at the intervals given in the table above.
6. If tank-mixing with an insecticide or fungicide, do a small jar-compatibility test first to confirm the products mix cleanly.

Precautions & Safety

• Do not mix with strongly acidic products or acidify the spray solution — thiosulphate breaks down in acidic conditions and can release sulphur.
• Avoid spraying during peak heat, bright midday sun or on wet foliage, to prevent leaf scorch.
• Do not exceed the recommended concentration; higher concentrations can burn leaves, especially on tender vegetable crops.
• Wear basic protective clothing and gloves while mixing and spraying, as a routine precaution for any agricultural input.
• This foliar/fertigation fertilizer is a supplement to, not a replacement for, balanced soil fertilization — follow your local agricultural extension advice on fitting it into your overall soil-nutrition programme.
• Store in the original, tightly closed container in a cool, dry place away from direct sunlight, food and feed, and out of reach of children and livestock.

Brand names mentioned on this page are registered trademarks of their respective owners and are referenced here for identification purposes only; FarmMate is not affiliated with or endorsed by these brands. This page is for general information only — always consult your local agricultural extension office (PAU Krishi Vigyan Kendra) and confirm current recommendations before use.