So, I love Spinach but apparently they are sprayed with a lot of insecticides to repel crop eating insects and this rules out Spinach for me. How worried should I be about the use of fertilizer for crop production?

P.S: I have been hearing a lot about sweet potatoes and how they are the perfect food but I was wondering how those were grown, do they use a lot of harmful fertilizer or anything along those lines?

Thanks for all your answers guys :)