A field trial was established in 2006 and in 2007 at two localities. The first one was in Lednice (district Břeclav) at an experimental plot of Department of Breeding and Propagation of Horticultural Plants. The second one was in Stařeč (district Třebíč). As model plants Acer pseudoplatanus and Quercus robur were used. As soil conditioners the following products were chosen: TerraCottem, Agrosil LR and Hydrogel. Both species were used at each stands. Model plants were planted out on plots with soil conditioners in 4 treatments (including a control treatment without soil conditioners) and 3 replications each. In the course of growing season, physiological parameters of plants were followed using special instruments Porometer AP 4 (stomatal conductivity), SunScan AT (PAR), and Chlorophyll Meter CCM 200 (chlorophyll contain index). Morphological parameters (i.e. the length of shoots and dry matter of leaves) were measured at the end of the growing season. The obtained data were statistically analyzed using the program Statgraphics Plus. The best results were obtained in treatments with soil conditioners. The soil conditioners influenced significantly both morphological and physiological parameters and eliminated effects of abiotic stressors on young plants of Acer pseudoplatanus and Quercus robur.