Sustainable Products, Projects and Green Design Luf Seedling Trays by Wenkai Xue Luf is a seedling tray made from loofah fiber. Luf replaces plastic trays with a biodegradable material formed from crushed loofah, a bio-based adhesive and a curing agent, which are heated and pressed in a mould. The trays stack together, so one person can carry more than five trays at a time. Each tray is divided into three independent parts and can be cut along marked lines. After the seedlings mature, the tray is planted into the soil, where it breaks down into nutrients. Loofah seeds can be collected and used for further cultivation.