2700K is better for flowering. If your using pre-ferted MG soil, and I do too, so it's not the end of the world like some would have you believe...just be careful adding anything else...read the plants...I usually just use 1/2 tablespoon of molasses (unsulphured blackstrap...get it at a healthy grocery store)as an additive every other watering towards the end, but I would rather underfeed than overfeed at this point of the grow...this helps it suck up more nutes when they start getting low in the soil towards the end of flowering...the plants will tell you when they need any other nutes while finishing up...study up on nutes (and deficiencies or overages)in the JC grow bible available here:
http://boards.cannabis.com/cannabis-...ideos-too.html
Especially study the pics! G/L!