Copper is necessary for photosynthesis and respiration.

Plants that are deficient in this nutrient will have yellow faded blotches that later turn a bronze or dull colour between veins on the oldest leaves, and later on the whole plant. The leaves will be small and the plant will be dwarfed. Flowers and buds decrease and fruits are poorly developed and are marred by sunken brown areas on their skin. Deficiency is mainly seen if there is too much peat in the soil, due to high pH reducing availability.

To correct a deficiency
  • Copper sulfate can be added to correct a deficiency but extreme care should be taken as too much copper can make the soil unfit for vegetable cultivation

Toxicity can result from using sprays of some fungicides, or even from plumbing used in the growing system.

To offset excessive Copper
  • Heavy liming can help remove some copper toxicity

Soil testing is an important activity for a successful garden. Soil stewardship is an ongoing process, where you test and amend, grow some stuff, then test, amend and grow some stuff….and so on. Focus on building soil tilth so it can really hold and make available to the plants all the important nutrients. You do this in part by adding compost, manure, rock dust, bone meal, kelp & fish emulsions. Read this article series to learn more about each of the 13 key nutrients for your garden.