Apple trees growing in a garden or a small, require granular or liquid fertilizers. Usually, granular fertilizer that requires a long period is better than the water-soluble fertilizer. This is because it will keep the nutrition level intact in the plant for a long time. It will also maintain the fertility of the soil for a comparatively longer duration without any sort of extra effort. But, if someone requires a faster effect, they can always opt for the liquid or water-soluble fertilizer.