It is used by the plant in the formation of chlorophyll, and is used to transport fluids. Copper deficiency in plants Copper deficiency first appears on the youngest leaves, showing up as yellowing, then dying leaf tips. In some plants, yellow patches appear on stems just below leaf nodes and later the patches can bulge out and fill with fluid. Copper deficient plants are pale from a lack of chlorophyll, and bear little or no fruit. Their growth including root growth is poor and leaves are mottled.
Grains are higher in copper content than stems or leaves of most plants.
Copper may affect the flavor of tomato, squash and cucumber and all are dwarfed and discolored when copper is deficient. Correcting copper deficiency in plants Copper is often reduced in peat-based soils or media. Copper sulfate can be added to water and used as a foliar spray for plants. It is often sprayed with lime to ensure the copper remains on foliage. This spray is called Bordeaux mixture and it is a common spray for use in fungal infections, and can be toxic to the plant if too strong in copper.