Vertical mulching with AirSpade is done to de-compact and augment soil deep into the tree root zone. This application is especially useful in areas with poor drainage, with shallow or impervious soils, or shared by perennial or ground-cover plantings, where minimal disturbance is desired.
Aeration and soil amendments from vertical mulching can encourage roots to grow deep into the soil profile, thereby improving the tree’s stability and volume of viable growing medium. Because vertical mulching affects the deepest soil profile, it is recommended for sites with shallow soil depth, hard-pan, anaerobic conditions, or other types of poor growing soils.
An appropriate soil augmentation strategy is vital and should be developed on a case-by-case basis. Vertical mulching can produce undesirable concentrations, or hotspots, of nutrients or organic matter, which can counter healthy, uniform root growth. For this reason, it’s advisable to use amendments that are compatible or blended with existing soils. For more extensive results, it is possible to perform vertical mulching over the course of several growing seasons.
Like other root zone soil treatments, vertical mulching is preferably done throughout the trees dripline or beyond. Once the layout, target depth, and size of holes has been determined, the operator can proceed with air-spading. Positioning the AirSpade perpendicular to the ground with the nozzle near the surface, the operator depresses the trigger and slowly pushes the tool into the soil. When resistance is met, the operator slowly withdraws the tool, clears the hole of loosened soil, and then reinserts. Excavated soil can be collected to be removed or augmented before the bore holes are refilled.
To learn more about performing air-spading procedures, tree health care and preservation, see the full Arbor Technical Applications Bulletin.