Efficient and scalable nursery practices are critical for sustainable reforestation, agroforestry expansion, and climate-resilient land management. Manual methods of filling poly-pots with sowing media and arrangement in nurseries are labour-intensive, time-consuming, and often lead to uneven bed layouts. This study presents the design, fabrication, and performance of a semi-mechanized poly-pot soil filling and arranging machine with the view to enhance nursery operational efficiency and reduce human drudgery. The machine was constructed using locally available mild steel, comprising of a 10×10 cylindrical casing matrix for 100 poly-pots, a lifting platform driven by a hand-operated screw lever, linear guide sleeves, and a mobile frame fitted with wheels for field movement. The design parameters, such as casing diameter (8.5 cm), lifting height (38.90 cm), and wheel spacing (12 cm), were carefully selected based on ergonomic and functional requirements for poly-pot alignment, ejection, and repositioning. Field trials were conducted to compare the time taken to complete one cycle (200 pots) between the machine and conventional manual methods across 20 replicates. Descriptive and inferential statistical analyses, including Welch’s t-test, were applied to determine the operational efficiency of the machine. The results revealed that the machine reduced average task completion time from 82.8 minutes to 53.2 minutes, representing a 36%-time savings, with the difference being statistically significant (p < 0.001). In addition to speed, the machine ensured uniform bed layout, enhanced worker ergonomics, and demonstrated stability and ease of use under field conditions. Its modular design also supports one-person operation while allowing for scalability with additional operators. The study concludes that this semi-mechanized solution offers a low-cost, high-efficiency alternative to manual nursery bed preparation, particularly in resource-limited agroforestry and reforestation settings. Adoption of this machine can contribute significantly to nursery throughput, operational consistency, and broader sustainability objectives.