Fulya Okatar, Mehmet Güneş
The aim of this study was to determine the effects of vermicompost (VC) and humic acid (HA) applications on the growth and development of “Transvaal” and “Dark Pink” gerbera (Gerbera jamesonii) cultivars. Peat and perlite mixture (2:1, v:v) was used as the growing medium, and fertilizer was applied throughout the experimental period to maintain an EC value of 1.1 dS m⁻¹. VC was prepared as 250 and 500 ppm, and HA was prepared as 500, 1000 and 2000 ppm doses. The prepared doses were mixed as follows: Control, 250VC+500HA, 250VC+1000HA, 500VC+1000HA an 500VC+2000HA. Mixture solutions (150 mL) was applied to each pot, while the control group treated with only 150 mL of water at the same intervals. The treatments began with seedling planting and were repeated every 15 days until harvest. Morphological parameters such as plant height, stem thickness, full flowering time, and yield were determined. The results indicated that VC and HA applications significantly shortened the time to full flowering and positively influenced the examined morphological traits, including stem length and stem thickness, in both gerbera cultivars. Development was most limited in the control group, whereas combinations of 500 ppm VC with 1000–2000 ppm HA promoted earlier flowering, stronger vegetative growth, and enhanced plant performance in both cultivars. In conclusion, VC and HA applications were found to be effective cultivation practices that support both vegetative and generative growth in “Transvaal” and “Dark Pink” gerbera cultivars.