Definition - What does Soil Drench mean?
A soil drench is a specific technique of applying a diluted chemical pesticide, herbicide, fungicide, or even fertilizer to a particular plant or tree, or to a specific group of plants, rather than the entire garden.
Rather than spraying an entire lot of plants, a soil drench is applied directly at the plants roots. With garden vegetable plants and other small-stemmed plants, the drench can be applied directly at the base of the stem. However, for trees, a trench should be dug at the base of the trunk and the drench poured into the trench.
MaximumYield explains Soil Drench
Plants are subject to a number of problems, ranging from infection by funguses to infestation by pests, to the need for additional nutrients and minerals to support healthy growth. It’s also common for just a single plant to experience such challenges, when its neighbors do not. A soil drench can help ensure that treatment is applied to the affected plant, without coming in contact with other plants in the area.
A soil drench is used to apply fungicides, herbicides, pesticides and even fertilizers to a specific plant. Unlike other application methods, the diluted liquid is not sprayed onto the plant or tree. This can lead to the liquid being carried by the wind onto other plants, or contaminating other plants due to overspray.
The soil drench method of applying fertilizers and pesticides also avoids the problems that can stem from using injection-style treatments on trees, and does not require much in the way of equipment beyond a bucket, mixing tools, and perhaps a rake or spade.
Note that while spray applications can often show immediate or fast results, soil drenches take more time. The chemical applied must make its way into the soil, and then be taken up by the roots, and sent into the trunk or stem, then the branches and leaves.
For a variation of the soil drench method, see the sprench method. It is a combination of a spray and a drench.