Used in an area of copper-deficient soil, copper sulphate enriches the soil and provides an essential nutrient to growing plants. When soil is copper-deficient, young plants may develop chlorosis, a condition in which leaves yellow due to lack of chlorophyll. Copper deficiencies can also cause stunted or atypical growth; young plants in very nutrient-deficient soil may simply die. Wilting, lack of flowers and reduced fruit harvest are all likely effects of copper-deficient soil. It prevents these problems. Test soil regularly, and apply copper sulphate as needed in a spray or fertilizer preparation.
It has anti-fungal properties, and is a key ingredient in some commercial fungicides for farm and garden. These fungicides are typically mixed with water and either lime or soda ash, then sprayed onto the plants. The effect of such a fungicide is prevention or reduction of fungal infections that can disease or destroy the plant. If a plant is already affected by fungus, fungicides may be effective in removing the fungus. This use is effective only if the fungicide is applied soon after fungal infection occurs.
Effects on Fruit
In fruiting plants, copper affects the sugar content and flavor of the fruits produced. The effects are most pronounced in blueberry, tomato, watermelon, onion, parsnip, lettuce, beet, carrot, cabbage, eggplant, celery and spinach plants. In general, water accumulation in a plant is lower, and therefore its taste is sweeter, when its conductivity is low. Excess amount increases conductivity, reducing the sugar concentration and flavor intensity of the fruit. If you want to grow sweet fruits that are not watery, ensure you are not over-applying copper sulphate to your plants.