Cu sulfate (25%)

Heavy Metals (PPM)

Arsenic       <10

Cadmium     <5

Mercury        <0.20

Lead         10

Nickel         <5

Source:   Data From Oregon Department of             Ag Organic Certification Database

Copper sulfate is used exclusively for increasing copper in the soil. It should only be used in small quantities validated by a soil test. Copper sulfate is the only significant source of copper that can be used in organic production (if a copper deficiency exists on a soil test).

Copper has a powerful anti-fungal effect systemically in the plant. It also increases the flexibility of stems and petioles.

Zinc sulfate should always be dissolved in water and drenched, sprayed, or fertigated for even distribution. Dry application is risky because the quantities required are too small to apply evenly.