Without such instructions from the company, many of us would probably put the fertilizer spikes near the trunk of a tree or shrub. But trees and shrubs are better served when we place fertilizer at the periphery of their roots, and that coincides with the farthest lateral extent of branches and leaves.
Like trees and shrubs, our ideas have a lateral extent, their farthest reach and the boundary where they meet other ideas. Our personal drip lines mark where we need intellectual fertilization if we are to have new ideas or extend the roots of our thoughts. An influx of nutrients works best at the drip line of the mind. Close in, the thick old tendrils of our neurons are less efficient at creative thought than those thin new offshoots exploring far from a well established trunk. New ideas lie at and beyond the boundaries of what we believe and know, that is, at our ideological and philosophical drip lines.
Ideologues keep fertilizing near the trunk. Everyone could learn a lesson from Miracle-Gro.