The current study was aimed to investigate the effect of different fertilization and biostimulant treatments on growth and flowering of Gerbera (Gerbera iamesonii cv. Jaguar Yellow) plant under unheated plastic greenhouse conditions. This study was carried out for two successive seasons of 2016/2017 and 2017/2018 at the farm of the Arid lands Agriculture graduated studies and Research Institute (ALARI), Shobra Elkheima area, Qalyobia governorate, Egypt. The experiment were laid out in a completely randomized design (CRD) with 3 replications, and the end results have been subjected to analysis of variance (ANOVA). Freshly extracted gerbera seedling have been planted into pots filled with peatmoss + sand (1:1), peatmoss + sand + vermicompost (1:1:1), peatmoss + sand + compost (1:1:1) with or without 250ml of Azotobacter + Azospirllum mixture, as biostimulant, and slow-release NPK (4.2g) or fast-release NPK (2.5g) fertilizers to each plant, to determine the effect of fertilizer, biostimulant and growing medium types on the production of potted gerbera. Growth and flowering characteristics were measured. Results indicated that medium combination of sand + vermicompost + peatmoss (1:1:1) with biostimulant, regardless of the fertilizer type, gave significantly increased results in all measurements, compared to all other combinations. Plants grown in medium supplemented with biostimulant and fast-release fertilizer, gave flowers with good qualities While the medium combination sand + vermicompost + peatmoss (1:1:1) with biostimulant in combination with either one of NPK mineral fertilizers (fast-release fertilizer and slow release fertilizer) gave significantly increased results in most parameters, shown in higher total vegetarian and quality when combined with slow release fertilizer than fast-release fertilizer. Under this treatment, plant length was (28.2 cm), number of leaves per plant was (24.8), stem diameter was (3.7 mm), fresh weight (47.9 g), seedings dry weight (12.5g), length of the longest tap root was (19.8 cm), diameter of tap root (2.9 mm), number of secondary roots (40.7), root/shoot ratio (2.57), Leaf greenness "SPAD 59", and the highest number of daughter plants (5.3/plant). These records were all significantly higher than other treatments