Been researching this stuff a lot... here's 2 different ratios that have a proven track record and are used by at least 2 LED companies.
6000k, Red & Deep Red 7:4:4
2 x 6500k , 1 x 430nm, 2 x 455nm (blues) : 9 red: (1 x 630nm, 4 x 640nm, 3 x 660nm): 1 infrared (730nm) 5:9:1
There's also some cats who think that a broad spectrum is more productive... so something like 12 x 4000k 3 x 2700k.. or maybe change out 2 of teh 4000k for 660nm