DRIP IRRIGATION
example, put all the grasses together, annuals on another zone and succulents that require less water on a separate zone. “Te environments can even vary on the same building. One corner might be more sunny, another more shaded and another more windy,” he says. “You have to factor that into the settings and make adjustments.” In the perfect scenario, Scott Todd, co-
owner of Innovative Irrigation Solutions in Rochester, New York, says spaghetti tubing with emitters matched to individual plant needs is the best option. It allows for mixing 0.5 gph to a drier plant like boxwoods, 1 gph to plants like arborvitae that need more water and 2 gph emitters on thirstier plants. Keane added that he installs filters on ev-
ery job. It doesn’t matter how clean the water source is; dirt and debris get into the lines and clog the micropore filtration. At the end of the season, the system is drained and flushed to eliminate any particles in the lines. “If you install dripline without using filters,
you’ll end up with problems because no water source is 100% clean,” he says.
3 INCORRECT PLACEMENT
A drip irrigation design must consid- er tubing and emitter placement to
provide the maximum moisture benefits to the root system, Navarra says. “I often see dripline run along only one side of the plant,” he says. “It needs to be on both to provide equal coverage and have a healthy, well-balanced plant.” How close the drip is located to the plant is just as important. For example, Navarra fre- quently sees drip in planter beds spaced 4 inch- es from the stump of a tree.
about 10 inches apart in larger containers de- pending on the growing media. One of the biggest errors Todd finds is mix-
ing rotors, sprays and dripline all on the same zone. On some jobs contractors run out of zones and don’t want the added expense of upgrading the clock. But “we’ll be called to a site where we know there is drip irrigation and the client says it’s not working,” he says. “We get there, walk around to the drip and find it’s running with sprinkler heads. Tere’s not enough pressure.” Todd adds that proper placement is as im-
portant with the stakes to hold the drip in place as it is in the dripline layout. He spaces staples no more than 6 inches to 8 inches apart on the dripline for nearly every application to pre- vent the line from shifting. Driving them in at 45-degree angles anchors them into the ground securely, he says.
4 MISUNDERSTANDING SOIL MEDIA
Failing to understand or account for the planting media is a common mis-
take. Knowing the soil’s water holding capacity, evapotranspiration rates, soil percolation and absorption is critical. Tese can vary from one site to the next and even in different locations on the same site. “I can’t emphasize knowing the growing media enough,” Navarra says. If the soil media is a heavy mulch that re- tains water, you will have to limit watering. If it’s clay-based soil, it’s essential to know this soil type prevents water from being absorbed. Loamy soil allows the water to percolate through before the plant has time to absorb the moisture. Too much or too little water can have neg- ative consequences. Underwatering in hot, dry
TAKE INTO ACCOUNT THE SOIL MEDIA BEING USED FOR PLANTING AND UNDERSTAND HOW TO MODIFY THE DRIP IRRIGATION TO BE EFFECTIVE.
“Te root hairs can’t absorb water that far
out from the main stem,” he says. Te same principle applies when using
microtubing and emitters in raised planters and hanging pots. Using only one emitter in the central ring of the planter doesn’t provide enough water for those plants along the perim- eter. In these scenarios, Navarra recommends using microtubing to accommodate multiple emitters. As a rule of thumb, he suggests using two
to three emitters inside 16-inch to 20-inch di- ameter pots. He recommends spacing emitters
22 Irrigation & Lighting Summer 2022
climates can lead to costly plant loss. Howev- er, regular site checks and supplemental hand watering create opportunities to make adjust- ments as needed at the first signs of stress. “Overwatering tends to be the bigger issue,”
Keane says. “My experience is that plants can get away with a lot less water than we think. You get more color, more flowers and blossoms, and less fungus and disease. You may have to supplement with hand watering, but it is worth the time and effort.” Todd agrees that too much water is a com- mon mistake on job sites. He only installs drip
irrigation on new plantings and only runs the system for a few years, until the planting is es- tablished. On older plantings on his projects, a system may only run in August if there are drought conditions.
5 INADEQUATE PRESSURE REGULATION
Pressure-compensating pipe is more costly upfront, but skimping at in-
stallation can have expensive long-term con- sequences. Without a pressure-compensating pipe, it’s impossible to maintain equal pressure from the head to the foot of the system, espe- cially if it is not a looped system. To guarantee the system has enough pres-
sure, Todd limits each drip zone to 2,000 feet per 45 psi high-flow regulator. He runs 1-inch line off the valve then splits the zone sending tubing 1,000 feet in one direction and 1,000 feet in another dividing the area in the middle rather than looping from front to back on the property. “We don’t reduce the main line down to
one-half inch until we get to the middle to be sure we get equal flow on both sides,” he says. Te best practice is to plan each zone with
consideration given to the water volume avail- able, Navarra explains. Pressure and volume drop as the distance from the water source increases, and when run in excess of the water availability the result is uneven water distribu- tion, which impacts plant health. Using friction loss calculations and manufacturer driplines specifications determine proper distance. “Some people try to cheat on that rule be-
cause they think they can push water further down the pipe without the pressure regulator,” he says. “It might work, but it creates other problems. Dripline is not manufactured to ex- ceed 35 to 40 pounds of pressure. Beyond that, you’ll start to get pipe failure.” Drip irrigation lets you deliver water pre-
cisely where you want it. Te systems are de- signed to provide a specific volume of water and nutrients where plants need it most, below the root zone. It limits moisture on plant ma- terial, reducing the opportunity for disease and fungus and providing equal water distribution. But like anything, simply avoiding these mistakes is not a cure-all solution. Instead, it takes knowledge and frequent monitoring to leverage a drip system’s benefits. Brushing up on the properties of soil media, evapotranspira- tion rates and friction loss are your best bet for having the greatest success with dripline irriga- tion systems.
Katie Navarra is a freelance writer in Mechanicville, New York, and can be reached at
ktnavarra@gmail.com.
irrigationandlighting.org
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