Aisles are expensive
A fixed-bench layout typically wastes a quarter of an expensive glasshouse on walkways that are occupied for a few minutes a day. Rolling benches keep one moving aisle and give the rest back to the crop.
Ebb and flood done properly
The tray floods to a controlled depth and drains back within a defined window. Slow drain-back is the most common cause of algae and root disease in bench systems, so fall and outlet sizing are calculated per bench length rather than taken from a catalogue default.
Cleaning between cycles
Anodised frames and open construction allow full washdown and chemical disinfection between propagation cycles without corroding fixings.