To create a cool and moist micro-climate conducive to seed germination, seed is covered with a layer of material after the sowing process. This layer also protects the seed during the germination phase. Mulching material is sometimes used to physically hold the seed in place and prohibit excessive growth of algae and moss.

The BCC Tray Covering Unit is used to cover trays with a thin and uniform layer of material after sowing. The unit is fully integrated into the BCC Filling and Sowing line.