Bonsai Jack (50 3x3 Inch Rigid Polyethylene Large Bonsai Pot Mesh Drainage Screens Manufactured in the USA Available in three sizes Screens an are important tool for the art of bonsai. They prevent soil loss, keep critters out and help prevent root rot. 1" screens are used for shohin(very small) pots. 2" screens are our best seller and work for most pots up to 10 inches. 3" screens work for large pots or medium pots with a single large hole.