Feed them a balanced fertilizer, and use something like 0-4-3 as soon as you see sex on top of that. after 2 feedings of the 0-4-3 (or similar), switch it up to a late flowering finisher with an added boost of P&K. I'd flush for at least a solid week before harvesting, more if using hydro. start them out running, and learn their limit as soon as you can so you can keep the nutrient buffet open.