An apparatus for forming a substrate, the apparatus comprising: a magazine (13) for storing one or more sheet elements (12) and a cutting device (22, 14) configured to cut an elongated growing substrate (11) from the edge of one or more sheet elements in the magazine, for being placed into an elongated trough for growing seeds and/or seedlings and wherein the apparatus is further configured to drop, to assist or to guide the cut-out growing substrate (11) into the trough. In an example, a side of said trough, which is parallel to the longitudinal direction of the trough, is totally or almost totally open. Furthermore, the apparatus is also configured to drop, to assist or to guide the cut-out growing substrate (11) into the trough through said open side. A system for growing plants comprises the above-described apparatus which is automated.
