Subsurface Drip Irrigation For Lawns & Home Landscapes

In these days of drought, heat spells, and water wise gardens, many gardeners are interested in efficiency when it comes to irrigation. Drip irrigation is commonly considered to be the most efficient way to water plants. But there’s something even better now: subsurface drip irrigation. It’s one step up – or, rather, one step down, providing low pressure water directly to each plant’s roots beneath the soil.

Subsurface drip irrigation – known as SDI – is an irrigation system that places a dripline of polyethylene tubing under the soil to release water to a plant’s root zone. Why is this good? The primary advantage of SDI is that the gardener is able to manage root zone irrigation more precisely. That means less evaporation loss and the possibility to spoon-feed nutrients.

An underground drip irrigation system also permits underground watering in fields that are shaped irregularly. In addition, it lets the gardener to meet the different water needs of different soils and crops.

The basic structure of an underground irrigation system is the dripline, buried in the soil. It must be placed below aeration depth, at least 6 to 12 inches below grade. An SDI dripline will have small holes called emitters spaced evenly along its length. The pressure of the water inside the tubing forces water out of the emitters drop by drop. Spacing between emitters depends on the type of soil and how it holds water.

The amount of water is regulated by the thickness of the dripline and the intervals of the emitters, usually placed every 8 to 24 inches (20-60 cm). You determine the appropriate spacing between by the soil’s water holding capacity.

The soil surface itself stays dry with subsurface drip irrigation, which means that neither the heat of