Why is one tray with holes and the other without holes?

Why is one tray with holes and the other without holes?

Our set of two plastic microgreen trays, crafted from UV-treated virgin plastic, is meticulously designed for nurturing microgreens. Each tray is 4cm in height, stackable for convenience, and equipped with drain holes. These trays are intended for indoor microgreen cultivation. One tray features drainage holes at the bottom, while the other remains hole-free. This dual-design allows for efficient bottom watering, as the tray with holes nests seamlessly within the hole-free tray, enabling the upward wicking of water to nurture your microgreens.