What is the primary coverage difference between commercial sprays and granular odor options?

Sprays coat leaves directly for topical protection

Commercial repellents offer an advantage over homemade granular options primarily through their application method and resulting coverage. Commercial sprays are formulated to be applied directly onto the foliage, offering immediate topical protection by coating the leaves themselves. In contrast, granular materials, such as blood meal or bone meal scattered around the base, primarily rely on the odor emanating from the soil or the base of the plant to create an aversion field. This difference in coverage means sprays offer direct taste/smell deterrence on the plant tissue itself, whereas granular products rely more on the immediate surrounding area.