To enhance the quality of onion seedlings and ensure stable production, the Taiwan Seed Improvement and Propagation Station (TSIPS) has been promoting the development of an “Onion Plug Tray Seedling Adaptation Technology” since 2024. This initiative integrates three core technologies—onion seed pelleting, facility-based plug tray seedling management, and gel solidification—while incorporating mechanical seeding and transplanting. The goal is to gradually establish a seedling production model that offers both disaster resilience and labor-saving benefits.

TSIPS noted that in recent years, intensifying extreme weather events and frequent heavy rainfall have posed serious challenges to onion seedling cultivation. Traditional open-field bare-root seedling practices are highly vulnerable to heavy rains, often resulting in waterlogged soils, damaged seedbeds, root rot, and uneven germination. Germination rates under such conditions typically reach only 60–70%, adversely affecting subsequent crop management and yield stability.

To address climate-related risks, TSIPS has introduced the onion plug tray seedling adaptation technology in combination with protected cultivation. This approach significantly improves water management and drainage, thereby reducing the impact of heavy rainfall on seedling production. In terms of technical application, seed pelleting is first employed to improve the handling of small and irregularly shaped onion seeds, enhancing sowing precision and uniform germination. Next, facility-based plug tray management is used alongside appropriate irrigation and fertilization control to produce uniform and vigorous seedlings. Finally, gel solidification treatment is applied prior to transplanting to stabilize the root media, improve the efficiency of mechanical transplanting, and effectively reduce labor requirements.

Experimental results indicate that the adoption of this technology increases onion germination rates to over 80%, with marked improvements in seedling uniformity and root system development, leading to significantly higher survival rates overall. Field trials in production areas further demonstrate that plug tray seedling technology not only mitigates the impact of heavy rainfall but also enables mechanized operations that reduce labor and time costs, thereby improving overall efficiency and scalability.

The technology will continue to be promoted in the future to assist farmers in establishing labor-saving and climate-resilient seedling production systems, helping the agricultural sector adapt to the challenges posed by climate change.

▲Figure 1. Onion plug tray seedling adaptation techniques