In order to manufacture an innerspring unit (31) comprising pocketed springs and having an increased stability at its edge regions, in a first step, an innerspring main body (30) comprising a plurality of first strings (14) of pocketed springs is provided. In a subsequent second step, at least one second string (13c, 13d) of pocketed springs is attached to a lateral surface of the innerspring main body (30), so that the at least one second string (13c, 13d) of pocketed springs extends in a longitudinal direction of the innerspring main body (30). The springs (13) of the at least one second string (13c, 13d) of pocketed springs have a spring characteristic or a spring geometry different from the springs of the plurality of first strings of the innerspring main body (30). The at least one second string (13c, 13d) of pocketed springs forms together with the innerspring main body (30) the innerspring unit (31).