Are the root feeders a good idea?
To be effective, you need to understand a few things about root feeders. First of all, it is essential that they are not pushed too far into the ground. In fact, six to eight inches is ideal. Because the probe is 2-3 feet long, it is tempting to push it further into the ground. But all you want to do is push it far enough to bypass the surface root systems of the surrounding turf or other ornamental plants. Research has shown that no matter how big that plant is, almost 95% of all the roots of trees and shrubs that actually absorb the water are within the top 12 inches of the soil. Trees and shrubs have roots that go deeper, but they are thicker roots whose job it is to stabilize the plants, not absorb water and nutrients. It is important to remember that the fertilizers in root feeders are water soluble and are used up quickly and for these reasons it is important use organic fertilizers.
