Even amongst landscape professionals, there is some confusion when it comes to the term "Organic Fertilizer".
In this FAQ, Christina Burton, Maintenance Channel Manager for Horizon, explains what organic fertilizer is and what your customer may really be asking for when requesting organic fertilizer for their lawn or landscape.
Organic Fertilizer Is Natural Fertilizer - Video Transcript
So what is organic fertilizer? Technically speaking, organic fertilizer is nothing but, definition meaning: it contains Carbon.
So in this sense there are a lot of synthetic fertilizers, your traditional “not natural” sources, like methylene urea, that contain Carbon. So by that definition, are organic.
Most likely if you’re looking for an organic fertilizer, what you really mean is you want something that’s natural. So containing natural components: broken down feather meal, bone meal, bio-solids or poultry wastes or other manures.
That’s really what you might be looking for when it comes to organic.