Copper Sulfate Pentahydrate (CuSO₄·5H₂O) is one of agriculture’s most time-tested and versatile inputs, serving as both an essential plant micronutrient and a broad-spectrum fungicide. With 25% copper in a highly soluble form, it corrects copper deficiencies and protects crops against damaging fungal and bacterial diseases. For over a century, this blue crystalline compound has been a foundation of integrated crop management, offering reliability, efficacy, and value.

I. Scientific Benefits: Nutrition and Protection in One Product

Essential Micronutrient Role
Copper is a catalyst for numerous enzymatic reactions. It activates enzymes involved in lignin synthesis, photosynthesis, respiration, and pollen formation. Adequate copper ensures strong cell walls, uniform growth, and proper reproductive development.

• Enzyme Activation: Copper is a cofactor for superoxide dismutase and other oxidative enzymes that protect plants from stress.
• Chlorophyll Stability: Copper helps maintain chlorophyll structure, delaying senescence and preserving photosynthetic capacity.
• Stress Tolerance: Copper-supplemented plants show improved resistance to drought, heat, and certain soil-borne stresses.

Broad-Spectrum Disease Control
Copper ions disrupt pathogen cell membranes and inhibit spore germination, providing contact protection against:

• Fungal Diseases: Downy mildew, powdery mildew, anthracnose, leaf spots, blights, rusts, and scab.
• Bacterial Diseases: Citrus canker, bacterial spot (tomato/pepper), fire blight (apple/pear), and bacterial wilt.
• Algae and Moss Control: Effective in irrigation systems, rice paddies, and on greenhouse surfaces.

Dual-Nutrient Contribution
The sulfate component provides 12.8% sulfur in plant-available form, supporting protein synthesis and enzyme function.

II. Deficiency Symptoms and Corrective Action

Typical Copper Deficiency Signs

• Cereals: Young leaves wilt, twist, or fail to unroll. Tillering is reduced. Heads may be empty or poorly filled (“white tip”).
• Fruit Trees (Citrus, Apple, Stone fruits): ”Summer dieback” of shoots, multiple buds at a node, fruit cracking, and gumming.
• Vegetables: Stunted growth, distorted new leaves, poor fruit set, and necrotic spots.
• General: Interveinal chlorosis on young leaves, followed by necrosis of growing points.

Conditions Leading to Deficiency

• Organic (peat) soils with high organic matter content
• Sandy soils with low cation exchange capacity
• High-pH (calcareous) soils where copper is fixed
• Intensive cropping with high nitrogen and phosphorus use

III. Application Methods and Recommended Rates

Soil Application (for long-term correction)

• Rate: 5–15 kg per hectare for deficient soils. For severe deficiency, up to 20 kg/ha.
• Timing: Apply before planting, broadcast and incorporate into the root zone.
• Frequency: One application typically supplies adequate copper for 3–5 years.
• Note: Excessive soil copper can be toxic; always soil-test before application.

Foliar Spray (for rapid correction and disease control)

• Concentration: 0.2–0.5% (200–500 g per 100 L water). For disease prevention, 0.3–0.6% is common.
• Timing: Early morning or late afternoon to avoid leaf burn.
• Frequency: Every 7–14 days for disease programs; 1–2 applications for deficiency correction.
• Additives: Use a non-ionic surfactant (0.1%) for better coverage.

Fertigation / Drip Irrigation

• Rate: 0.5–2.0 kg per hectare per application as a dilute solution.
• Compatibility: Fully soluble; will not clog emitters if filtered.
• Caution: Do not mix with alkaline fertilizers (e.g., calcium nitrate) in the tank.

Seed Treatment (for cereals)

• Concentration: 0.1–0.3% solution; soak seeds for 10–15 minutes.
• Benefit: Protects seedlings from soil-borne pathogens and supplies early copper.

Bordeaux Mixture Preparation

• Mix copper sulfate and hydrated lime in a 1:1 to 1:2 ratio (e.g., 1 kg copper sulfate + 1 kg lime in 100 L water).
• Use for orchard disease control (e.g., apple scab, grape downy mildew) during dormant or early growth stages.

IV. Technical Specifications

• Chemical Formula: CuSO₄·5H₂O
• Copper Content: ≥25.0%
• Sulfur Content: 12.8% (as sulfate)
• Solubility: 320 g/L at 20°C
• Appearance: Blue crystalline granules or powder
• pH (1% solution): 3.5–4.5
• Heavy Metals: As ≤10 ppm, Pb ≤20 ppm, Cd ≤2 ppm

Available Grades

• Agricultural Grade: Standard purity for field use.
• Fine Crystal Grade: Rapid dissolution for foliar and fertigation.
• OMRI Listed: For organic production (some formulations).

V. Performance Evidence

Deficiency Correction

• Field trials show that foliar copper sulfate (0.3%) corrects visible deficiency symptoms in wheat within 7–10 days.
• In citrus, soil application at 10 kg/ha raised leaf copper levels from deficient (3 ppm) to adequate (8–12 ppm) within one season.

Disease Control Efficacy

• Downy mildew on grapes: 85–95% control with 0.3% copper sulfate applied at 10-day intervals.
• Citrus canker: 70–90% reduction in lesion number when trees are sprayed with copper-based products three times per year.
• Bacterial spot on tomatoes: Significant suppression with weekly applications starting at transplant.

Yield and Quality Response

• Copper-deficient cereals: 20–35% yield increase after correction.
• Apples: Improved fruit finish and reduced cracking with dormant copper sprays.
• Vegetables: Higher marketable yield due to reduced blemishes and longer shelf life.

VI. Compatibility and Safety

Mixing Guidelines

• Compatible with: Most neutral-pH pesticides, fungicides, and foliar nutrients. Always conduct a jar test first.
• Incompatible with: Highly alkaline materials (lime water, Bordeaux mixture except in formulated form), oils (may increase phytotoxicity), and concentrated phosphate solutions.

Phytotoxicity Prevention

• Do not apply during hot (>30°C) or humid conditions.
• Avoid use on copper-sensitive crops (e.g., some stone fruits) unless proven safe.
• Do not exceed recommended rates, especially on young foliage.

Environmental and Worker Safety

• Copper is highly toxic to aquatic organisms; avoid drift into water bodies.
• Use protective gloves, goggles, and dust mask during handling.
• Wash thoroughly after contact. In case of eye exposure, flush with water and seek medical attention.

Storage

• Keep in original closed container in cool, dry, well-ventilated area.
• Protect from moisture and heat. Shelf life: 24 months.

VII. Why Choose Our Copper Sulfate Pentahydrate

• High Purity: Low heavy metal content ensures crop safety and environmental compliance.
• Consistent Quality: Batch-to-batch uniformity, with ISO 9001 certification.
• Versatile Forms: Crystalline and powder options for all application methods.
• Technical Support: Agronomic advice tailored to your crops, soil conditions, and disease pressures.
• Global Reach: Reliable supply from multiple production hubs.

VIII. Ordering and Technical Support

Product Availability

• 25 kg moisture-proof bags (powder or crystals)
• 1-ton bulk bags
• Custom packaging upon request

Services

• Soil and tissue test interpretation
• Deficiency diagnosis and treatment planning
• Disease management program development
• Equipment calibration guidance
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