Centre Liam Steel was next on the scoresheet, scoring under the posts after a 17-phase movement.
A depleted Taniwha scored through flanker Aorangi Stokes. It was a glimmer of hope for the visitors.
When Ropate Rinakama crossed the tryline, the Taniwha trailed 26-14. But the Steamers were able to keep their noses in front with an opportunist effort to fullback Chase Tiatia.
Scott Gregory's bust and offload set up Tamati Tua and then on the stroke of fulltime, Gregory again cut open the Steamers' defence to put wing Jordan Hyland in the corner.
Bay of Plenty 38 (James Lay, Jeff Thwaites, Liam Steel, Emoni Narawa, Fa'asiu Fuatai, Chase Tiatia tries; Kaleb Trask 4 con)
Northland 35 (Aorangi Stokes, Ropate Rinakama, Noah Cooper, Tamati Tua, Jordan Hyland tries; Jack Debreczeni 3 con, Wiseguy Faiane 2 con)
HT: 26-7 BOP