This research investigates how different nutrient supplements affect the tensile strength of a bio-welded connection between two mycelium specimens. The experiments are conducted using oyster mushroom (Pleurotus ostreatus) mycelium grown on cotton wool as the primary growth medium. To isolate the influence of nutrient composition, all other experimental variables - including fungal species, growth medium, temperature, humidity, and cultivation time - are kept constant. Four supplementation conditions are compared: dextrose (glucose), malt extract, yeast extract, and a control group without additional nutrients. These supplements were selected to represent different balances of carbohydrates and nitrogen, two essential resources required for fungal growth and hyphal development. First, the mycelium is added to the cotton wool growth medium. Then, the supplements are dissolved in distilled water and applied to the inoculated cotton wool, allowing the nutrient solution to be absorbed and distributed through the substrate. Two mycelium inoculated specimens are positioned in direct contact with one another enabling the fungal hyphae to form a bio-welded interface. Throughout the cultivation period, the development of the weld is documented through visual observations of mycelial growth and the morphology of the connection. Before testing the tensile strength, the bio-welded specimens are dried first. To evaluate the mechanical performance of the resulting bio-welds, a custom tensile testing apparatus was designed and built specifically for this project. The testing system combines an Arduino-controlled stepper motor with a load cell to apply a steadily increasing tensile force until the welded connection fails. During testing, the load cell continuously records the applied force, which is converted into Newtons to determine the maximum tensile strength of each specimen. By comparing the tensile strength and observed growth behavior across the four supplementation strategies, this study aims to provide a better understanding of how nutrient availability influences bio-welding performance and to contribute to the ongoing development of reliable mycelium-based materials for sustainable architectural applications.