Whether you are trying to conserve water or ease your watering workload or both, drip irrigation—a network of plastic tubing and low-volume drippers and sprinklers that reach every part of the garden you want to water—takes the hassle out of watering.
The materials are fairly inexpensive and easy to install using nothing more than scissors or shears and a special hole punch tool. Once you lay out the tubing and connect the drippers, sprinklers or sprayers, you’ll be able to water your plants by simply turning on the water and letting it run for 20 minutes more or less each day. Add a battery-operated controller and you won’t even have to remember to turn on the water. It’ll turn the water on and off automatically at the times you select.
Drip irrigation saves more than time and energy; it saves water by distributing it more efficiently. Because you use dozens of watering devices to replace one regular sprinkler, you have much greater control over where the water goes and how much is supplied to each plant. Instead of flooding the ground all at once, micro-irrigation lets you apply a small amount over longer periods, allowing the water to soak into the plants’ root zone for the most benefit. And since runoff and evaporation are kept to a minimum, drip irrigation uses less water.
The basic planning strategy is to pick the best watering device to serve each type of plant. Then determine a flow rate that supplies adequate water to every plant in the watering zone. Set up the system to run between one and two hours at a time, two or three times a week.
Step 1: Measure your garden and make a simple sketch. Choose the type and flow rate of the watering devices based on your soil and the plants’ water needs. Mark these on the drip irrigation system plan and draw in the tubing route to connect them. This will involve a little guesswork, but drip “emitter” packaging always states the gallons per hour “GPH” it will flow to your plants.
Step 2: Choose Types of Emitters (drip sprinkler) and Connectors
Drippers: Use these to water individual plants, or buy ‘inline’ drippers and use them in a series with a 1/4-in. tube. Drippers work great for container plants too. They’re color-coded for different flow rates between 1/2 gph and 4 gph.
Soaker: Soaker drip line consists of 1/4-in. porous tubing that “leaks” along its whole length. You can use it to encircle shrubs and large plants or lay it out in a grid pattern as a substitute for sprinklers in a densely planted flowerbed.
Bubblers: A cross between drippers and sprayers, many bubblers are adjustable for flows up to 35 gph and diameters to 18 in. Since they put out more water than drippers, they’re good for larger plants like roses, tomatoes, and shrubs.
Sprinklers: These are miniature versions of sprinklers you might use in the yard. Most have flow rates between 14 and 40 gph and cover a radius of 3 to 30 ft. Since most sprinklers have a relatively high flow rate, you can’t use more than about 15 or 20 in one zone of 1/2-in. tubing.
Sprayers: These are like sprinklers without moving parts. You can choose a spray pattern from a quarter circle up to a full circle, or buy sprayers with adjustable spray patterns. They spray from 4 to 34 gph and up to a radius of about 12 ft. Use sprayers to water ground cover or densely planted flowerbeds.
Fittings: Drip tubing connectors come in a wide variety of angles/shapes so when you have turns or junctions in your layout, you can accommodate it by cutting the mainline tubing, attaching the 90-degree elbow for a turn, a “T” adaptor to keep the line going straight and allow for a second “lane” to continue left or right.
Extension tubing: 1/4” tubing connects your water flow from the main line to the exact spot you want a dripper/emitter or soaker tubing.
Tubing Connectors: Buy enough barbed tubing connectors to attach all of your mainline tubing to 1/4” tubing. The connectors come in 90-degree elbows, T-connectors, and end caps for terminating the tubing.
Flush End Cap: Purchase a flush end cap fitting to attach to the end of each 1/4” mainline to allow flushing the system at the end of each watering season.
Tools: The only tools needed are shears or tubing cutter and a hole punch. You can purchase a manual hole punch for a few dollars or a more automatic gripping hole punch for anywhere from $10 to $15.
Because there are many manufacturers of drip irrigation parts (and most are good quality and reputable like Raindrip, Orbit, DIG, etc.) there are also varying specifications on diameter of tubing sizes and thus the associated adaptors. It’s important to keep in mind the brand you start with and the specifications (outside diameter) of the main line tubing so that when you change/expand your drip system, you buy adapters that fit your existing lines. For instance, if you shop Lowe’s or Wilco, you’ll see drip system parts by Raindrip (Rainbird), but if you shop Home Depot, you’ll see drip system parts by DIG. DIG 1/2” main line tubing has an outside diameter (OD) of .700”, while Raindrip main line tubing has an OD of .620”. Orbit adaptors won’t fit on Raindrip main line tubing and vice versa.
Basic Rules of Thumb
– Use 1/2-gph drippers in clay soil,1-gph drippers in loam and 2-gph drippers in sandy soil.
– Add the gallons per hour (gph) rate of all drippers, bubblers, sprayers and sprinklers you plan to use. If you’re using 1/2-in. tubing for the main line, limit the total to between 150 and 220 gallons per hour (check with the manufacturer).
– Limit the length of 1/2-in. tubing on one zone to a maximum of about 200 ft.
– Limit the total gph on a length of 1/4-in. tubing to 25 to 30.
Step 3: Add a “Y” faucet adaptor so you can attach your drip system to one side and keep the functionality of attaching a garden hose to the other when needed.
Step 4: Lay out your main line (1/2” tubing). Connect the 1/2-in. poly tubing to the faucet end. Then lay the tubing through the garden according to your plan. Stake it down about every 5 or 6 ft, and cut the tubing with pruning shears or tubing cutter and install T- and 90-degree fittings where they’re needed. Twist and press the tubing firmly into the fitting.
Step 5: Punch holes where you want each of your emitters to go.
Step 6: Press a barbed connector/sprinkler or dripper into the hole in the 1/2-in. tubing. If the 1/4-in. tubing isn’t already attached, add a length of 1/4-in. tubing to reach your dripper, sprayer or sprinkler location.
Step 7: Sit back and enjoy your new automated system Add a battery operated controller at the faucet end of the system to make it even more automatic and allow watering to take place on a schedule even when you aren’t able to be home.