Drip irrigation is a water delivery system that uses low pressure to target water directly to plant roots. It involves a network of tubing and emitters that slowly release small, measured amounts of water. The answer is yes, you can bury drip irrigation tubing, though success and longevity depend heavily on the type of tubing and installation method. Burial of these lines is often referred to as Subsurface Drip Irrigation (SDI), a specialized application of the technology.
Benefits and Considerations for Subsurface Placement
Burying drip lines offers several distinct advantages over surface installation. Placing the tubing beneath the soil shields the polyethylene material from ultraviolet (UV) radiation, which causes plastic to become brittle and degrade over time. This protection significantly extends the lifespan of the system. Water conservation is also enhanced because burial virtually eliminates surface evaporation, ensuring nearly all the water reaches the root zone.
Aesthetics and safety are also improved by removing visible hoses that can be unsightly or present a tripping hazard in garden beds and lawns. Standard drip lines are typically only covered lightly with mulch or soil (around 0–2 inches) for aesthetic reasons. True Subsurface Drip Irrigation involves using pressure-compensating emitters specifically engineered for permanent burial, which ensures consistent water delivery regardless of changes in elevation or tube length.
Proper Techniques for Burial Depth and Installation
The depth for burying drip lines varies depending on the application and soil type. For general garden beds and vegetable gardens, a shallow depth of 2 to 4 inches is often sufficient to protect the lines from light cultivation and UV exposure. In contrast, permanent SDI systems installed in lawns or agricultural fields require burial depths between 6 and 12 inches to prevent damage from deeper soil disturbance like aeration or tilling. Soil composition plays a role; sandy soils may require deeper placement to allow for lateral water spread, while clay soils can utilize a shallower depth due to their higher water retention.
Connections, valves, and flush points should be placed above ground or housed within accessible valve boxes for future maintenance. Before the trenches are backfilled, the system should be pressurized and thoroughly flushed to remove any soil, debris, or plastic shavings introduced during trenching. This initial flush prevents immediate clogging once the system is buried. The tubing should be laid flat in the trench, without sharp bends or kinks, to maintain consistent water pressure and flow uniformity.
Managing Clogging and Subsurface Maintenance
Subsurface drip systems face maintenance challenges, with clogging and root intrusion being the most common causes of failure. Clogging can be categorized into three main types: physical, chemical, and biological. Physical clogging occurs from sediment or debris entering the system. Chemical clogging results from mineral precipitation, such as calcium carbonate, especially in hard water areas with a pH above 7.0. Biological clogging is caused by the growth of bacterial slimes and algae within the tubing.
Preventative measures must be integrated into the system design, starting with mandatory filtration, often requiring a mesh size specific to the emitter type to screen out physical contaminants. Chemical treatments, such as periodic acid injection (using nitric, phosphoric, or sulfuric acid), are used to dissolve mineral precipitates and lower the water’s pH. For biological growth, periodic chlorination or the injection of other oxidizers helps to break down the organic slime.
Root intrusion, where plant roots grow directly into the emitter openings seeking water, is a primary concern for buried systems. Specialized SDI tubing is designed with root deterrents, such as copper-impregnated emitters, which release minute amounts of copper to discourage root growth without harming the plant. Maintenance also involves a regular flushing schedule, where the ends of the lateral lines are opened to flush out any accumulated sediment. If a leak occurs, tracing the source in a buried system can be difficult, often requiring the system to be pressurized to identify wet spots that indicate a breach, which may be caused by rodents chewing the plastic.