There are organic herbicides and fertilizers. Among those there are organic post emergents which are either selective or non selective. The organic pre emergents don't work well (corn gluten meal). Organic use of herbicide will have a much bigger impact than organic fertilizers in my opinion and I'm still learning about them. Whatever herbicide you use you really want systemic herbicides that work. I personally use flame engineering
products as a non selective and am going to try out but have heard great things about ADIOS as a selective herbicide. Both are of course systemic. There is also the Frostbite
weed system but they want to rip you off. They're selling the backpack systems for 3,000 dollars, no thanks. PM phasthound about ADIOS.