It bears a hole in its middle, designed to insert an Araponics seed holder (http://www.araponics.com/) and supports the aerial rosette. Rhizoponics blueprints and 3D files are provided in the Additional files 2 and 3. Piece profiles could be easily adapted to other homemade seed starting systems, e.g. pierced microcentrifuge tubes [16,17], or to other hydroponics tanks.