The purpose of the experiment was to assess the effect of application of zinc ammonium acetate (ZAA) on yielding, morphological features and on selected vegetation indices of timothy cv. ‘Owacja’ cultivated for seeds. Zinc ammonium acetate that has a biostimulatory effect was used foliar in the carried out experiment. The experiment was conducted in the years 2015-2017 at the experimental station in Prusy near Krakow, a part of the Experimental Station of the Institute of Crop Production of the University of Agriculture in Krakow. The field experiment was set up in a randomized block design, in four replications, and the area of experimental plots was 10 m2. Degraded Chernozem formed from loess (classified to the first class quality soil) was present on the experimental area. The experiment consisted in applying ZAA as spray at three doses: 0.214, 0.267 and 0.400 kg(ZnNH4(CH3CO2)3)/ha. Based on the obtained preliminary results, it was found that application of foliar activator in a higher dose (0.400 kg/ha) caused a significant (