A plant plug holder is provided which is designed to be inserted within a cut-out in a hydroponic tower. The plant plug holder includes (i) an edge member that encircles the holder's opening and which may be sealed to the front tower surface; (ii) a base member configured to support the plant plug and which extends rearward from the edge member and into the central cavity of the tower; (iii) a rear shroud top member that inhibits leakage as well as plug erosion; (iv) a pair of side members that maintain the position of the plant plug within the plug holder; and (v) a plurality of open regions configured to promote water drainage from the top surface of the base member.