Emitter tubing is a specialized type of drip irrigation line with water outlets integrated directly into the tubing wall during manufacturing. This system is a highly efficient method of water delivery, designed to supply moisture directly to the root zone of plants, minimizing the water loss that occurs through evaporation or runoff in traditional watering methods. Its main purpose is to conserve water while ensuring uniform hydration for plants, making it a popular choice in both agriculture and residential gardening.
The Mechanics of Water Delivery
The fundamental function of emitter tubing relies on the small, built-in devices, known as emitters or drippers, strategically placed along the line. These emitters act as precision regulators, controlling the volume and flow rate of water discharged from the tubing.
The internal mechanism of the emitter is designed to convert the relatively high pressure of the water supply into a slow, measured drip. Many modern emitters feature a tortuous path or a maze-like channel that the water is forced to navigate. This long, narrow pathway dissipates the water’s pressure through friction, creating a controlled, low-flow discharge, typically between 0.5 and 2.0 gallons per hour (GPH).
In more advanced designs, a diaphragm or flexible seal is incorporated to manage pressure fluctuations. This mechanism ensures that even if the water pressure in the main line changes due to varying terrain or long tubing runs, the emitter maintains its specified output rate. To protect the system and ensure the emitters operate within their intended range, a pressure regulator is typically installed at the water source, reducing the incoming pressure to the lower levels required for drip irrigation, often between 10 and 25 PSI.
Choosing the Right Emitter Tubing
Selecting the appropriate emitter tubing involves considering the terrain, the length of the runs, and the specific needs of the plants. A primary distinction is between pressure compensating (PC) and non-pressure compensating tubing. Pressure compensating emitters contain an internal diaphragm that adjusts to pressure changes, delivering a consistent flow rate even on slopes or over long distances, which is particularly useful when elevation varies by more than five feet.
Non-pressure compensating emitters are less expensive and work well for small, flat garden areas where the water pressure remains relatively stable. Their flow rate will vary with changes in pressure and elevation, meaning plants at the beginning of a run or at a lower elevation may receive more water than others. For the most reliable and uniform water delivery across a large or sloped area, PC tubing is the preferred choice.
Emitter spacing is another factor, with common options ranging from 12 to 36 inches apart, and the choice should be guided by soil type and plant density. In sandy soils, where water tends to move vertically with little horizontal spread, closer spacing is necessary to ensure the root zone is fully wetted. Conversely, in loamy or clay soils, which spread water more broadly, a wider spacing, such as 18 to 24 inches, is often sufficient. The flow rate, measured in GPH, is selected based on the plant’s water requirement and the soil’s absorption rate. A 1 GPH emitter is standard for many applications, but 2 GPH emitters are often recommended for sandy soils or plants with high water needs. Tubing diameter, typically 1/2-inch or 5/8-inch, determines the maximum length a run can be before pressure loss affects uniformity.
Installation and Placement Guidelines
A typical emitter tubing setup begins with connecting the system to a water source and incorporating a filter to remove sediment, which is essential to prevent the small emitter openings from clogging. Laying out the tubing involves running the main line through the planting area, ensuring it is positioned directly adjacent to the plants that need water. For rows of plants, the tubing is laid in straight, parallel runs, but for larger, individual plants like shrubs or trees, the tubing can be formed into a loop around the plant’s drip line. The end of each tubing run must be sealed with an end cap to maintain system pressure.
The physical line should be secured to the ground using plastic stakes or pins every few feet to prevent shifting and ensure the emitters remain in the correct location near the root zone. Ongoing maintenance primarily focuses on preventing and treating clogs, the most common issue in drip irrigation. Periodic flushing of the lines, which involves temporarily removing the end caps to allow a rush of water to clear any accumulated debris, is also recommended. Systems should be regularly inspected for leaks, which are usually fixed by tightening connections or using small repair couplers.