Drip irrigation has revolutionized the way gardens are watered. Because the system delivers water at the soil surface, much less water evaporates. Plus, drip emitters are very precise; they can be placed exactly where plants need water. Watering with a sprinkler saturates an entire area unnecessarily. A drip-irrigation system can be quite elaborate or small and simple, which affects its installation. The easiest way to get started is to use a garden hose to supply water to the system.
Uncoil a roll of 1/2-inch-diameter drip tubing around the plants that need to be irrigated, starting at the plants that are closest to the water source. Secure the tubing to the ground near each plant by using U-shaped, metal tubing staples, each 6 inches long, as you uncoil the tubing. At the end of the area you want to irrigate, cut the tubing, and leave the tubing’s cut end open.
Punch one hole with a drip emitter installation tool in the 1/2-inch-diameter drip tubing where the tubing is next to one plant, and insert a drip emitter in the hole. Repeat the procedure to punch a hole and insert a drip emitter in the tubing next to each plant. Use 1/2 gallon per hour (GPH) emitters for perennial small plants, 1 GPH emitters for shrubs and 2 GPH emitters for trees. Adjust the location of the tubing as needed to get the emitters directly above the root zones of the plants.
Slide a barbed drip-to-hose thread coupler with a 1/2 inch diameter into the end of the 1/2-inch-diameter drip tubing that is closest to the water source. Thread a 15-pounds-per-square-inch (psi) pressure reducer onto the drip-to-hose thread coupler.
Thread a back-flow prevention device onto the pressure reducer. Thread the end of the garden hose into the back-flow prevention device. Turn on the water to the garden hose.
Stand at the 1/2-inch-diameter drip tubing’s end that was left open, and wait for the water to come out that end. Let the water flush dirt and other debris from the drip tubing for 10 to 20 seconds. Insert a drip tubing end cap in the end of the drip tubing.
Verify that water flows from all the drip emitters. If necessary, adjust the location of the emitters to ensure they distribute water directly over the root zones of all the plants.
- The 1/2-inch-diameter drip tubing should wind its way through the planting area, but it does not need to pass by every plant directly. A drip emitter can be attached to the end of 1/4-inch-diamter supply tubing, and the supply tubing can be plugged into the 1/2-inch-diameter drip tubing by using a 1/4-inch-diameter barbed coupling. Use the drip emitter installation tool to punch a hole in the 1/2-inch-diameter drip tubing so you can insert the 1/4-inch-diameter supply tubing. Uncoil the 1/4-inch tubing to a plant, cut that tubing and push a drip emitter into its end. Use a U-shaped, metal tubing staple to hold the emitter in the proper location.
- Barbed T couplings can be inserted into 1/2-inch-diamter drip tubing at any point to distribute water to another area of the garden.
- The 1/2-inch-diameter drip tubing can be laid only in broad, gentle curves. The tubing kinks if it is used to make a sharp angle. Barbed elbow couplings can be inserted into the tubing where it needs to pass around a sharp corner.
- A barbed straight coupling can be used to splice together two pieces of 1/2-inch-diameter drip tubing.
- If a hole is punched in the wrong place in the 1/2-inch-diamter drip tubing, insert a 1/4-inch-diameter tubing plug in the hole.
- Remove the cap at the end of the drip tubing to prevent freeze damage in winter when the system is not in use.
- Drip emitters can become clogged with the tiniest bit of sediment in water. Flush the drip-irrigation system each spring before you re-insert the end cap in the drip tubing.
Brian Barth works in the fields of landscape architecture and urban planning and is co-founder of Urban Agriculture, Inc., an Atlanta-based design firm where he is head environmental consultant. He holds a Master’s Degree in Environmental Planning and Design from the University of Georgia. His blog, Food for Thought, explores the themes of land use, urban agriculture, and environmental literacy.