Copper is an indispensable micronutrient for plants, and copper sulfate pentahydrate (CuSO₄·5H₂O) is the most trusted source of soluble copper in agriculture. With 25% copper and 12.8% sulfur in fully water‑soluble form, this blue crystalline product corrects copper deficiency and protects crops against a wide range of fungal and bacterial diseases. For growers who want to improve plant vigour, prevent hidden hunger, and reduce disease pressure without relying solely on synthetic fungicides, our high‑purity copper sulfate delivers reliable, dual‑action performance.

I. Why Copper is Critical for Crop Health

Copper acts as a cofactor for many enzymes involved in:

• Photosynthesis and respiration – Copper is a component of plastocyanin, a protein that transfers electrons during photosynthesis.
• Lignin synthesis – Copper strengthens cell walls, improving standability and resistance to pathogens.
• Pollen formation and fertilisation – Adequate copper increases pollen viability and fruit set.
• Stress tolerance – Copper‑dependent antioxidant enzymes help plants withstand drought, heat, and oxidative stress.

Even mild copper deficiency reduces yield and quality. Because copper is immobile in plants, deficiency symptoms appear first on young leaves and growing points.

II. Recognising Copper Deficiency

Typical symptoms

• Cereals (wheat, barley, oats): Young leaves wilt, turn pale green or white, and may fail to unroll. Heads are malformed or empty (“white tip”).
• Citrus and fruit trees: “Summer dieback” of shoots, multiple buds at a node, fruit cracking, gumming, and poor colour.
• Vegetables (tomato, onion, lettuce): Stunted growth, distorted new leaves, necrotic spots, and poor fruit set.
• Vines (grape): Interveinal chlorosis of young leaves, shoot dieback, and reduced berry set.

Copper deficiency is common on organic (peat) soils, sandy soils low in organic matter, and highly weathered tropical soils. It can also be induced by excessive nitrogen or phosphorus fertilization.

III. Copper as a Broad‑Spectrum Fungicide / Bactericide

Copper ions disrupt the cell membranes and enzymes of fungal spores and bacteria, providing effective contact protection with a multi‑site mode of action – resistance is rare.

Diseases controlled

• Fungal diseases: Downy mildew (grape, cucurbits, onion), powdery mildew, leaf spots, anthracnose, early and late blight (potato, tomato), apple scab, brown rot, and Alternaria.
• Bacterial diseases: Citrus canker, fire blight (apple, pear), bacterial spot (pepper, tomato), bacterial blight (cotton, beans), and walnut blight.
• Algae and moss: Copper sulfate is also used to control algae in irrigation ponds and rice paddies.

IV. Application Methods and Recommendations

A. Soil Application (for copper nutrition, long‑term correction)

• Rate: 5–15 kg per hectare on most deficient soils; 20–25 kg/ha on organic or highly leached sands.
• Timing: Pre‑plant, broadcast and incorporate into the root zone (top 10–15 cm).
• Frequency: A single application supplies adequate copper for 3–5 years on many soils. Over‑use can cause toxicity – always base on soil test.

B. Foliar Spray (for rapid deficiency correction and disease control)

For copper deficiency:

• Concentration: 0.2–0.5% solution (200–500 g per 100 L water). Use 300–500 L spray solution per hectare.
• Timing: At first sign of deficiency; repeat after 10–14 days if needed.
• Additive: Non‑ionic surfactant (0.1%) improves leaf coverage.

For disease control (protectant):

• Concentration: 0.5–1.0% (500–1000 g per 100 L water) – higher rates for dormant trees (2–3%).
• Timing: Start before disease appears; repeat every 7–14 days during favourable conditions.
• Important: Do not apply during bloom (toxic to bees) or in hot, humid weather (phytotoxicity risk). For sensitive crops, prepare Bordeaux mixture (add lime to neutralise acidity).

C. Seed Treatment

• Concentration: 0.1–0.3% solution; soak seeds for 10–15 minutes before planting.
• Benefit: Controls seed‑borne pathogens and provides early copper nutrition.

D. Fertigation (limited use)

• Copper sulfate is fully soluble but can react with phosphates and alkaline water. For drip systems, use only in short, separate injection events, or use chelated copper for regular fertigation.

V. Technical Specifications (Agricultural Grade)

Chemical properties

• Formula: CuSO₄·5H₂O
• Copper (Cu): 25.0% minimum
• Sulfur (S): 12.8% (as SO₄)
• Solubility: 320 g/L at 20°C (fully soluble)
• pH of 1% solution: 3.5–4.5

Physical properties

• Appearance: Blue crystalline powder or granules
• Particle size: 0.5–2.0 mm (crystalline), fine powder available
• Bulk density: 1000–1200 kg/m³
• Moisture: ≤ 1.0%

Quality standards

• Purity: ≥ 98.0%
• Heavy metals: As ≤ 10 ppm, Pb ≤ 20 ppm, Cd ≤ 2 ppm
• Insoluble matter: ≤ 0.1%

VI. Crop‑Specific Benefits

Grapes (wine and table)

• For downy mildew: Apply 0.3–0.5% copper sulfate mixed with lime (Bordeaux) every 10–14 days from early shoot growth to after flowering.
• Results: Effective disease control, improved berry set and colour.

Citrus

• Soil application: 10–15 kg/ha every 3 years prevents deficiency (“yellow leaf”, twig dieback).
• For canker control: 0.5% copper spray after each flush of new growth.

Tomatoes and potatoes

• Foliar: 0.2–0.3% at first sign of early or late blight.
• Results: Suppresses blight, improves fruit set and tuber quality.

Cereals (wheat, barley)

• Soil pre‑plant: 10–15 kg/ha prevents “white tip”.
• Foliar: 0.25% at tillering if deficiency appears.

Onions

• Foliar: 0.2% copper sulfate helps control downy mildew and improves bulb firmness.

VII. Environmental and Safety Precautions

Phytotoxicity prevention

• Do not apply during hot (>30°C), dry, or humid conditions.
• On sensitive crops (e.g., stone fruits), use diluted sprays with lime (Bordeaux mixture).
• Always follow recommended rates.

Worker safety

• Copper sulfate is irritating to skin and eyes. Wear gloves, goggles, and a dust mask.
• In case of eye contact, flush with water for 15 minutes. If swallowed, do not induce vomiting; drink water and seek medical advice.

Environmental protection

• Copper is highly toxic to fish and aquatic organisms. Avoid runoff or overspray into water bodies.
• Do not contaminate ponds, streams, or ditches with product or used containers.

Storage

• Store in original sealed bags in a cool, dry, well‑ventilated area, away from food, feed, and alkaline materials. Shelf life: 24 months.

VIII. Quality Assurance and Certifications

Our copper sulfate pentahydrate is produced in ISO 9001:2015 and ISO 14001:2015 certified facilities. Each batch is tested for copper content, heavy metals, solubility, and particle size. Certificates of Analysis are provided with every shipment. OMRI‑listed grades (for organic farming) are available.

IX. Why Choose Our Copper Sulfate

• High purity – Low heavy metals, safe for foliar and soil use on all crops.
• Rapid solubility – Fine crystals dissolve quickly in cold water.
• Consistent particle size – Uniform blending and easy handling.
• Dual function – Corrects copper deficiency while providing proven disease control.
• Technical support – Our agronomists help with deficiency diagnosis, rate calculation, and Bordeaux mixture preparation.