Deep root-soil injection consists of placing a probe into the soil surrounding the root systems of trees and injecting a liquid formulation under pressure. The formulation varies according to tree species, needs, time of year, and factors such as known diseases present, pH of the soil, and the customer’s landscaping plans.
A typical formulation for trees in and around Jackson, Wyoming includes a mixture of
- Evergreen Special 30-7-10 Slow release, low salt nitrogen, phosphorous, and potash nutrient is safe and effective
- Humates - Humic acid-based and totally organic that increases the uptake ability of the plant and increases the water holding capacity of the soil, reduces soil tension.
- Chelated iron - Source of iron for correction of chlorosis in trees growing in slightly acid to slightly alkaline soils.
Other sub-soil injection additives are used as may be needed to provide the appropriate nutrient balance for species and soil types.
- Colonized bacteria for soil ecology, particularly important for recent transplants
- Sulfur to adjust pH
- Insecticide to prevent Coolie Spruce Gall attacks in evergreen – reduce airborne pesticide usage later in the growing season
Spring and Fall are both good times of year to inject deep root fertilizers, and slow-release allows safe application without fear of “burning out” root systems. The presence of pathogens may suggest applications for some species in the Fall and at other times it might be best to fertilize in the spring as well, to boost the nutrient content of the soil.