yes you can use flowering nutes if you diden`t use any nuted during veg. I would just start out a little less then recommended at first. and you start the nutes 10 to 14 days into flowering. And FYI if i was you on your next grow i would always use nutes, when used properly even in a really good soil mix can make a huge diffence. Hope this helps, if you need more help post back.