Sulfate of Potash (0-0-50-18S) in fine powder form is the ultimate chloride‑free, fully water‑soluble potassium fertilizer for high‑value crops. With 50% K₂O and 18% sulfur in plant‑available sulfate form, our SOP powder dissolves instantly in water, making it the preferred choice for foliar sprays, drip irrigation, hydroponics, and liquid fertilizer blends. For growers targeting premium markets, superior fruit quality, and export compliance, SOP powder delivers unmatched purity and performance.

I. Why Choose SOP Powder Over Granular SOP

Instant Dissolution for Precision Application
Unlike granular SOP, which may take minutes to hours to dissolve, our fine powder (≤0.2 mm) disperses and dissolves completely within seconds in cold water. This allows for rapid preparation of stock solutions, eliminates sediment in spray tanks, and prevents clogging of drip emitters, mist nozzles, and fine‑mesh filters.

Ideal for Foliar Feeding
The fine powder creates a stable, uniform solution that can be sprayed directly onto leaves. Foliar application of SOP provides fast potassium and sulfur uptake, bypassing soil fixation issues, especially during fruit development and stress periods.

Seamless Integration into Liquid Blends
As a raw material for water‑soluble NPK blends, SOP powder mixes evenly with other soluble ingredients (urea, MKP, magnesium sulfate, micronutrients). Its fine particle size ensures homogeneity in the final bag and complete dissolution in the field.

Higher Purity, Lower Impurities
Our powder grade is manufactured to exceed standard agricultural specifications, with chloride below 0.5%, sodium below 0.2%, and heavy metals within the strictest limits. This makes it safe for even the most chloride‑sensitive crops (tobacco, berries, citrus, potatoes) and for use in soilless systems.

II. Key Agronomic Benefits of SOP (Potassium Sulfate)

Chloride‑Free Potassium Source
Potassium from SOP is accompanied by sulfate, not chloride. This eliminates the risk of chloride toxicity, which causes leaf scorch, reduced growth, and lower fruit quality in sensitive crops. SOP is the only potassium fertilizer approved for many export‑oriented fruit and vegetable programs.

Dual Nutrient Supply (K + S)
SOP provides 50% K₂O plus 18% sulfur in the sulfate form. Sulfur is essential for protein synthesis, enzyme activation, and the formation of glucosinolates (flavor compounds) in mustard family crops, as well as oil synthesis in canola and sunflower.

Low Salt Index
The salt index of SOP is much lower than that of potassium chloride (MOP), reducing the risk of root burn when applied as a band, side‑dress, or through fertigation. This allows safe use at higher concentrations in starter fertilizers.

Improves Fruit Quality and Stress Tolerance
Adequate potassium from SOP increases fruit size, uniform colour, sugar content (Brix), and shelf life. It also strengthens plant cell walls, improving resistance to drought, frost, and diseases.

III. Application Methods and Rates

Foliar Spray

• Concentration: 0.5–1.5% solution (500–1500 g per 100 L water). Use 300–500 L of spray solution per hectare.
• Timing: Apply at early bloom, full bloom, and fruit enlargement stages. For stress recovery, apply after hail or drought.
• Frequency: 2–3 applications spaced 10–14 days apart.
• Additive: Use a non‑ionic surfactant (0.1%) to improve leaf coverage.
• Response: Greener leaves, stronger stems, improved fruit colour and firmness within 7–10 days.

Fertigation (Drip, Sprinkler)

• Rate: 5–15 kg per hectare per application, depending on crop and growth stage.
• Concentration: 0.5–1.5 g per liter of irrigation water (EC 0.7–2.0 mS/cm).
• Frequency: Weekly or bi‑weekly from flowering through fruit fill.
• Advantage: Provides precise, continuous potassium and sulfur to the root zone without clogging emitters.

Hydroponic Nutrient Solutions

• Target potassium: 150–250 ppm K (as K₂O equivalent).
• Use SOP powder as the primary potassium source (blend with potassium nitrate and calcium nitrate for balanced nutrition).
• pH after mixing: 5.8–6.2; SOP has a neutral pH effect.

Soil Application (as a soluble top‑dress or side‑dress)

• Rate: 150–300 kg per hectare, depending on soil test and crop demand.
• Method: Dissolve in water and apply as a drench, or blend with dry fertilizer and water in immediately.
• Benefit: Suitable for furrow‑irrigated or rain‑fed crops where fertigation is not available.

Seed Treatment or Transplant Dip

• Concentration: 0.5% solution for soaking seeds or dipping seedling roots.
• Benefit: Provides early potassium and sulfur, reducing transplant shock.

IV. Technical Specifications (SOP Powder, Soluble Grade)

Chemical Properties

• Potassium (K₂O): 50% minimum (actual K: 41.5%)
• Sulfur (S): 18% minimum (as SO₄)
• Chloride (Cl): ≤ 0.5% (typically <0.2%)
• Sodium (Na): ≤ 0.2%
• Moisture: ≤ 0.5%

Physical Properties

• Appearance: White, free‑flowing fine powder
• Particle size: 95% passing through 0.2 mm mesh (typical D90 = 150 µm)
• Bulk density: 1100–1300 kg/m³
• Solubility: 120 g/L at 20°C (complete dissolution)
• pH of 1% solution: 6.0–8.0 (neutral)

Quality Standards

• Purity: ≥ 99% K₂SO₄ equivalent
• Heavy metals: Cd ≤ 1 ppm, Pb ≤ 2 ppm, As ≤ 1 ppm
• Insoluble matter: ≤ 0.05%

V. Crop‑Specific Recommendations

Fruit Trees (Citrus, Apple, Grape, Mango)

• Foliar spray: 0.5–1.0% at petal fall, fruit set, and colour break. Increases fruit size, sugar content, and storability.
• Fertigation: 10–15 kg/ha per week during fruit development. Reduces pre‑harvest drop and cracking.

Vegetable Crops (Tomato, Pepper, Cucumber, Eggplant)

• Foliar: 0.5% at first flower and again at fruit set. Prevents blossom‑end rot (with adequate calcium) and improves fruit firmness.
• Fertigation: 8–12 kg/ha every 5–7 days from flowering to harvest. Extends harvest period.

Potatoes

• Foliar: 1% at tuber initiation and bulking. Increases specific gravity, reduces hollow heart.
• Fertigation: 10–15 kg/ha per week during bulking.

Berries (Strawberry, Blueberry, Raspberry)

• Drip fertigation: 5–10 kg/ha per week from bloom through harvest. Improves flavour, colour, and post‑harvest life.

Onions and Garlic

• Foliar or fertigation: 0.5% solution at bulb initiation and again 2 weeks later. Increases bulb size and storage quality.

Tobacco

• Foliar: 0.5% every 2 weeks after transplanting. Chloride‑free potassium prevents leaf burn and improves combustibility.

VI. Advantages Over Other Potassium Sources

Versus Potassium Chloride (MOP)

• SOP powder contains no chloride (MOP has ~47% Cl), making it safe for sensitive crops.
• Provides essential sulfur (MOP has none).
• Lower salt index means less risk of root or leaf burn.

Versus Potassium Nitrate (NOP)

• SOP provides sulfur (NOP has none) and has no nitrogen, making it ideal for late‑season applications where extra nitrogen would delay maturity or reduce quality.
• More economical per unit of potassium for many crops.

Versus Granular SOP

• Powder dissolves instantly for foliar and liquid applications; granular is slower and leaves residues.
• Powder produces more uniform blends with other fine ingredients.

VII. Environmental and Safety Profile

Soil and Water
SOP is not acidifying; it leaves no harmful residues. Sulfur is an essential plant nutrient, and chloride levels are negligible. Over‑application can raise soil electrical conductivity, but proper rates are safe.

Worker Safety
SOP powder may cause mild eye or respiratory irritation from dust. Wear gloves, goggles, and a dust mask when handling large volumes. In case of eye contact, flush with water. If swallowed, drink water and seek medical advice.

Storage
Store in original sealed bags in a cool, dry, well‑ventilated area. Protect from moisture to prevent caking. Shelf life: 36 months.

VIII. Quality Assurance and Certifications

Our SOP powder is manufactured in ISO 9001:2015 and ISO 14001:2015 certified facilities. Each batch is tested for K₂O, S, Cl, Na, moisture, particle size, and heavy metals. Certificates of Analysis are provided with every shipment. OMRI‑listed (organic) and Halal/Kosher grades available.

IX. Why Choose Our SOP Powder

• Rapid dissolution – Complete solubility in cold water within seconds, no sediment.
• Ultra‑fine particle size – Uniform powder ensures homogeneous blends and consistent performance.
• Low chloride and sodium – Safe for even the most sensitive high‑value crops.
• Technical support – Our agronomists provide fertigation schedules, foliar programs, and tank mix compatibility advice.
• Flexible packaging – 25 kg bags, 1000 kg FIBCs, and bulk containers.