Seated rows can't be beaten for back hypertrophy. Whether you go light or heavy, you can use them to build all the right places: mid-back, upper back, lats, and even rear delts to some extent.
If you can find an iso-lateral row machine, use it. It's cool how much variety you can get out of one machine just by changing your rep scheme, grip, load, or extending the time under tension. Here's one of my favorite ways to use it:
Iso-Lateral Row: 10-10-10 Method
First, pick a weight heavy enough that you can't row it bilaterally (both arms) for more than 12 reps.
Note: When you row with both arms instead of one, you fatigue faster because you're doing double the work. So choose the appropriate weight. If you go too light, no biggie, just increase the challenge by upping the time under tension (TUT), so pause at the hardest point in the rep and lower slowly. Then add weight on your next set.
Using the grip you prefer (I like a neutral grip for these) work through the following:
- Do 10 reps with both arms. Set both handles down and immediately...
- Do 10 reps with one arm. Set that handle down and immediately...
- Do 10 reps with the other arm.
Aim for 3-4 sets of this. Ramp up in weight after each set if you can. Go heavy enough that it's a challenge, but not so heavy that you can't feel the target muscles working. Rest long enough to catch your breath, then go again.