In this scientific article, the effect of biological fertilization on the formation of buds and leaves, the length of leaves, the number of fibrous roots, the length and weight of roots of saffron are studied. Based on the obtained results, it was determined that the amount of zoohumus at a concentration of 30 g/5l has a positive effect on the formation of buds, the weight of buds, the number of leaves and the length of leaves, fibrous roots, their length and weight. Also, it was observed that the indicators obtained on the effect of saffron grown in zoohumus-based substrates with a concentration of 60-100 g/5l on the formation and size of female corms decreased compared to saffron grown in zoohumus substrates with concentrations of 10 g/5l, 20 g/5l, 40 g/5l and 50 g/5l. Therefore, it was determined that it is appropriate to accept a concentration of 30g/5l as the concentration that has an optimal effect on the formation of saffron female corms and their size.