Sheep wool can be a waste products of sheep husbandry. Its safe utilization evokes several serious problems. Therefore, it was of interest to check out the usefulness of wool as a fertilizer and/or substrate. The aim of the experiments reported in this paper was to evaluate the effect of the washed sheep wool used as an amendment to peat-based growing substrate on growth and yield of tomato, sweet pepper, and eggplant. The layer of wool was spread on 5 cm thick strata of substrate and covered with the same substrate at a rate of 10 g wool per 1 dm³ of substrate. Plants were grown individually in containers. It was stated that the addition of wool caused up to 33% higher yields, especially for tomato and pepper. Wool amendment caused changes in nutrients content of substrate and leaves. Thus, sheep wool can serve as a valuable and environmentally friendly fertilizer.