Star Plug Trays promote vertical (downward) root growth that encourages plugs to root out faster while developing strong, healthy root systems. Top vent holes provide even air flow throughout the tray to further promote healthy vigorous growth habit. Well-rooted plugs establish faster when bumped up to a larger container. Trays have UV resistance and improved strength, resulting in longer service life in the field.from T.O. Plastics, Inc.