Copper plays a big role in producing healthy plants, stems, branches and new growths, as well as in plants reproduction and maturity and also assists in carbohydrate metabolism and oxygen reduction.Copper deficiency plants shows lack of growth, growth tips die back, green leaves will show bluish hue and plants may have a hard time showing maturity in vegging stages.
Copper deficient plants cause irregular growth and wilting in newer growth. The leaves at top will wilt easily along with bleaching (chlorosis) and necrotic areas in the leaves,turning them yellowish. Leaves on the top of the plant may show veinal chlorosis. Growth and yield will be diminished. Too much copper in the system will cause the plant to die, as if it was a poison.
Some new growths may not open up, along with becoming thin pale green to a bluish hue. Copper is absorbed best in soil at a pH level of 5.0-7.5 Copper is absorbed best in hydro and soilless mediums at pH levels of 2.0-6.0

Treat a copper deficiency by foliar feeding with copper sulphate. Any nutrients with copper in them will fix a copper deficiency such as garden manure and Greensand. Damaged leaves will NOT recover, so prune them off.