This study aimed to evaluate the effects of Sinabung volcanic ash and banana peel waste extract as planting media amendments on the growth performance of potato plantlets during the acclimatization stage, considering different application times. The experiment was conducted in the screen house at Technical Implementation Unit of The Horticultural Seed Center in North Sumatra, Indonesia. The experimental design was arranged in a completely randomized factorial design with three factors and three replications. The first factor was three levels of volcanic ash percentage (V), namely V0 = 0% volcanic ash + 100% soil, V1 = 25% volcanic ash + 75% soil, V2 = 50% volcanic ash + 50% soil. While the second factor was concentration of banana peel extract (P), namely P0 = 0 ml/1, P1 = 5 ml/1, P2 = 10 m/1, P3 = 15 ml/l, and P4 = 20 ml/1. The third factor was application time of banana peel extract (H), namely H0 = at transplanting, H1 = 7 days before transplanting, and H2 = 14 days before transplanting. Observed parameters included plantlets survival percentage (%), plantlets height (cm), the number of planlets leaves (unit), and stem diameter (mm). The research results showed that the treatments of volcanic ash, banana peel extract concentration, and timing of banana peel extract application had a significant effect on the survival percentage, height, number of leaves, and stem diameter of plantlets. For plantlet survival percentage, number of leaves, and stem diameter, the best results were obtained with treatments V2, P2, and H2. Meanwhile, for plantlet height, the best results were found with treatments V2, P3, and H2. The interaction between V and P showed the best results with the combination V2P2 for plantlet survival percentage and number of leaves, while for plantlet height and stem diameter, the best results were obtained with treatment V2P3. The interaction between V and H showed that the best combination was V2H2 for all parameters. The interaction between P and H produced the best results with the combination P2H2 for plantlet survival percentage, and P3H2 for plantlet height and number of leaves. For the interaction among three treatments, the best combinations were V2P2H2 for plantlet survival percentage and stem diameter, V2P3H2 for plantlet height, and V2P2H1 for number of leaves