The growth of the world's population is an increasing challenge for agricultural production. Improving soil productivity is the key to ensuring the quantity, quality and safety of food for a growing population. In addition to macroelements, microelements also play an important role in the biochemical processes. A large percentage of soils in Hungary show a deficiency in copper. For three years, we treated the leaves of winter wheat with a copper-tetramine-sulphate complex derived from microelectronic waste. Aim to provide an alkaline pH range of 9.3 for effective foliar treatment. Treatments were applied on 10 m² small plots at 0; 0.1; 0.3; 0.5; 1.0; and 2.0 kg×ha^-1 copper dose in the budding and flowering phenological stages with copper-tetramine-sulphate produced from microelectronic waste. After harvesting the crop from the plots, the yield, raw protein, and gluten content were measured. In the copper-deficient soil, a significant increase in yield and protein and gluten levels was observed after treatment with copper foliar fertiliser. The most significant increase in yield was obtained in the treatment at flowering (0.40 t/ha), with a 0.37 % increase in crude protein content and a 1.95 % increase in wet gluten content.