Because of escalating interest in water conservation, Delta Bluegrass has introduced five different California Native turfgrass blends over the last seven years that are 50 to 70 percent more water efficient than traditional varieties.
To showcase these new varieties, Delta Bluegrass created two research and development areas that provide statistics and education on these products, along with information on irrigation.
Designed primarily for landscape architects and contractors, the newest demonstration area is a 2,000 square-foot site located in front of the Delta Bluegrass corporate offices, which is open year-round to visiting industry professionals and their clients.
Along with the company’s most popular traditional blends, including Bolero PlusT Dwarf Fescue, the demonstration area showcases new California Native varieties. These include Native Mow Free, Native Bentgrass, Delta Grasslands Mix, Native Preservation and Biofiltration Sod.
"Professional interest in low maintenance, water saving turfgrass has been soaring," reported Vita Perez, sod marketing manager at Delta Bluegrass.
"Landscape architects, golf course designers and contractors call inquiring about our recommendations for their projects and with questions about the most efficient way to water new varieties, both traditional and native," she said.
"That’s why the SSDI (subsurface drip irrigation) system was a key component in our corporate demonstration site."
The Delta Bluegrass team asked Netafim District Sales Manager Bob Best to devise a below-grade dripline irrigation plan. They wanted to demonstrate that the water-conserving varieties could indeed thrive with less water in challenging conditions, such as Stockton’s hot and dry, 100+ summers.
Best recommended Netafim Techline CV dripline and created a plan with 2,000 feet of tubing that incorporated emitter spacings every 12 inches. Because the site had very loamy, peat soil with a high infiltration rate, he specified a low flow rate of .4 GPH (gallons per hour). Matching flow rate to soil type is one of the advantages of dripline irrigation. The .4 GPH rate allows the water to percolate down to the root zones without puddling or run-off.
The dripline was installed 4 inches below grade and the rows of tubing were placed 12 inches apart. The new sod, which was about 1.5-inch thick, was set on top.
Best also recommended that the tubing start within 2 inches of the hardscape.
"Heat from the hardscape can create a hot zone so it’s best to place dripline within 2 inches of walkways or patios so the turf or plantings have more direct access to water. This eliminates dry edges," he said.
A pre-assembled Netafim Low Volume Control Zone Kit (LVCZ-S8010075-HF) was installed with a 1-inch valve, 140 mesh filter and pressure regulator. The kit fit into a standard 12-inch rectangular valve box. The system operates at 43 psi and is run by a Hunter I-Core Controller programmed with a low flow dripline schedule.
The scheduling was designed to match Stockton’s historic summer ET (evapotranspiration) rate. The irrigation is set to run approximately 24 minutes daily on two cycle and soak schedules. The water runs for 12 minutes in the morning and 12 minutes in the afternoon.
"We recommend a lull of three to four hours in between irrigation cycles so the water can be absorbed more efficiently," said Best.
"This also promotes capillary action. For example, frequent on-off cycling of a zone helps move water as far outward, upward and downward from the dripline as possible, which helps stimulate root growth."
During the first 10 days, the site was watered 40 minutes per day (two run times at 20 minutes each) with a four-hour soak time in between. Supplemental hand watering was used for the first two weeks to help the roots become established.
As the seasons change, the watering schedule will be cut back to 10 minutes a day during the fall and three minutes a day during the winter. This is based on 100 percent Eto from historical data for the Stockton area.
As spring approaches, the schedule will be modified to reflect 50 percent of Eto, and will run approximately 5 to 6 minutes per cycle.
"Dripline works really well with new California Native Grasses. Some of these Natives can grow from 6-in. to 12-in, tall and it is difficult for overhead sprays to efficiently cover them. This is not a problem for dripline. We can also irrigate any time of the day or night – and not have to worry about wet walkways, or overspray on cars or windows," said Perez.