Consumption of vegetables with either too low or excessive contents of micronutrients may have an adverse effect on human health. In intensive horticultural production mineral fertilizers, containing mineral or chelate compounds with varying micronutrient fertilization efficiency, constitute the main sources of micronutrients for plants. In the years 2009–2010 experiments with lettuce were conducted to investigate the effect of mineral (sulfates) and chelate (IDHA chelate, EDTA + DTPA chelate) forms of copper, zinc and manganese on yield and micronutrient contents in leaves. Two levels of micronutrients were applied (mg∙ dm^-3 of substrate): I. 5 Cu, 10 Zn, 10 Mn, and II. 20 Cu, 40 Zn and 40 Mn. Lettuce was grown in 6 dm³ containers filled with limed highmoor peat, enriched with macro- and micronutrients. Lettuce was harvested at the consumption stage. Contents of Cu, Zn and Mn were determined by ASA in lettuce leaves. The volume of lettuce yield at a lower content of micronutrients in the substrate did not depend on the form in which copper, zinc and manganese were introduced. After the application of higher rates of micronutrients in the mineral or IDHA chelate forms a significantly higher crop was produced than in case of EDTA + DTPA chelates. An increase in micronutrient rates in the substrate had a significant effect on an increase in their contents in vegetables. At the nutrition of crops with micronutrients at higher rates in the form of EDTA + DTPA chelates a significant increase was found in copper content in lettuce. After the application of higher rates of micronutrients plants that were introduced two micronutrients in the IDHA chelate forms and one in the mineral form contained less zinc. Leaves of lettuce grown on substrate with mineral forms of copper, zinc and manganese contained significantly more manganese than those grown in substrate with chelate forms of micronutrients.

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