Just as Xeriscape principles can be used for developing landscapes that conserve water using a variety of plants, these principles can be employed for the use of turfgrass alone as well. Some strategies include:
· Prepare soils for turf areas as carefully as any other planting area to use all the moisture available, promoting the plant’s vigor and water-use efficiency.
· Place turf species in landscape zones based on water requirements. Select adapted turf species and varieties that have lower water demands.
· Irrigate turf in areas that provide function (i.e. recreational, aesthetic, foot traffic, dust and noise abatement, glare reduction, temperature mitigation).
· Use non-irrigated turf areas where and when appropriate
· Irrigate turf based on true water needs
· Decrease fertilization rates and properly schedule fertilization
· Use turfgrass in areas of the landscape where it provides function.
In addition, design the landscape based on plant-water needs by appropriately placing turf for function, benefit and water efficiency. Zoning the landscape allows for watering turfgrass on a more frequent schedule than shrubs. For established trees and shrubs, the irrigation strategy should use deep soil moisture and depend on natural rainfall to replenish soil moisture.
Finally, a very important strategy when incorporating turf into the landscape while conserving water is to select the most appropriate turfgrass species and varieties. There are significant differences in water requirements among turf species and even among varieties within species. Some species avoid and resist drought better than others. Choose species and varieties that are both adapted to the area and have the lowest practical water requirements, while still meeting other site and use requirements.
After selecting the proper turfgrass, be aware of drought-stress indicators. Watch for a range of color changes, leaf curl and wilting. Based on plant behavior, strive to meet the water needs of each group of plants and irrigate only when the plants require water (versus by the calendar) to dramatically reduce landscape water use. Finally, decrease fertilizer application rates and use timely applications of slow-release fertilizers to reduce flushes of growth that can increase water requirements.
Before droughts or maximum heat days occur, take preventive measures to ensure healthy turf throughout the summer months. To increase water infiltration, implement dethatching or hollow-core aerification of all lawn areas, as well as under the drip line of trees. Till garden areas to break up surface crusting adding mulch where appropriate. Trim or prune trees, shrubs and bushes to remove low-hanging, broken or diseased parts and allow greater sunlight penetration throughout and beneath the plant.
Fertilize all plants when soil temperatures reach at least 50 F with a balanced plant food that contains nitrogen, phosphorous and potassium according to the results of soil testing or as experience has shown is appropriate. Sharpen pruning shears and mower blades to help prevent plant water losses and the introduction of disease. Establish or confirm soil type(s) to match water infiltration rates with future water-application rates and to determine if soil pH adjustments are recommended.
Other preventive measures include performing irrigation-system maintenance, regardless of type (hose-end, drip, in-ground, etc.) to ensure maximum uniformity of coverage and overall operation. At the same time, repair or replace broken or damaged nozzles or heads and flush drip system emitters to ensure proper flow. Ensure rainfall shutoffs and other irrigation system devices are working properly. Install hose-end water timers for all hose bibs and adjust in-ground system controllers according to the plant’s seasonal needs. Upgrade in-ground systems by adding soil-moisture meters, rain shutoff devices or evapotranspiration (ET)-based controllers.
To ensure the most effective water application, relocate drip emitters, particularly around trees to the outer edge of their drip lines. Confirm water-application rates for hose-end or automatic systems to determine the actual running times required to distribute a specified amount of the water to the selected plants, water the turf in the early morning when wind and heat are lowest. Irrigate all plants infrequently and deeply according to local ET or soil-moisture requirements to establish a deep, healthy root system. Cycle irrigation applications (on-off-on-off) to allow penetration and avoid runoff.
Begin regular mowing when grass blades are one-third higher than desired post-mowing length and keep clippings on the lawn. Finally, raise mowing height as summer progresses to the highest acceptable level to encourage deep rooting.
While properly preparing turf for maximum heat days and droughts in advance can help ensure a healthy lawn and conserve water, other practices can keep landscapes looking good during the hottest days and worst droughts. First, withhold fertilizers, particularly nitrogen, on turfgrass. (However, small amounts of potassium will aid in developing more efficient roots.) Reduce mowing frequency to minimize wear and possible soil compaction. Adjust automatic timers of in-ground systems according to the plant’s seasonally changing water needs.
If dormant turf appearance is acceptable, eliminate all traffic on turf areas. This includes mowing, which will probably not be necessary because of the extremely slow growth rate. Adjust automatic timers to manual or use hose-end sprinklers to apply approximately ¼-inch of water a week. Finally, minimize water applications for all plant materials to the essential amounts needed to maintain plant vitality.
After periods of drought or maximum heat days have ended, irrigate all plants to re-establish soil-moisture levels, beginning with staged increases in watering to progress toward a deep and infrequent watering practice. In addition, gradually lengthen the running times, but add greater amounts or time between watering applications.
Newly designed and installed landscape areas offer tremendous opportunity to create a beautiful space, while at the same time using turfgrass to conserve water. First, with the Xeriscape principles, which were outlined last week, in mind begin planning and design. The principles provide practical guidelines for landscapes that are beautiful and conserve water in the most efficient manner.
Next, implement efficient irrigation practices. Do not overwater, modify settings of irrigation systems for seasonal plant water-use changes and install systems that include soil-moisture meters, rain shut-off devices or multi-station programs for efficiency. Take other measures such as soil analysis and improvements before planting, selecting appropriate plans and establishing new lawns with turfgrass sod instead of seed. Finally, to further conserve water, harvest and re-use the water that is available.
While implementing all of the practices outlined above will help to conserve water with turfgrass, it’s important for irrigation and landscape managers to use those practices that make the most sense for the particular landscape they are maintaining. Keep conservation top of mind and using turfgrass to assist in that conservation is the first step to sustaining landscapes that are beautiful, use water efficiently and add benefit to the environment.
The author is executive director, International Turf Producers Foundation, Rolling Meadows, Ill.