1. TURF WATERING Edited by: Vincent Mannino, County Extension Director Texas A&M AgriLife Extension Service

2. Watering your lawn seems like a simple task, yet there is more to it in Texas! It is about –Knowing about how much water is needed –Producing a “healthy grass” that can persist on the least amount of irrigation water –Knowing how to water your lawn efficiently for the good of the lawn –Keeping applied water on your landscape by avoiding misapplication and runoff which can carry sediment, nutrients and pesticides AND wastes water!

3. Average Annual Rainfall 50” 40”30” 20” 10” 5” Rainfall lessens as you go west. Irrigation requirement is greater in west Texas for the same grass one would grow in East Texas (Bermuda grass)

4. What do I need to know about my lawn and how does that influence how I water?

5. Most homeowners ask… 1. What do I need to know about my lawn (soil type, grass type, surface slopes, what sprinkler system is used to apply water) and how does that influence how I water? 2. How do I know when my lawn truly needs water? 3. How often should irrigation water be applied? 4. How much irrigation water should be applied? 5. What time of day to water? 6. How long does my irrigation system need to operate to apply the right amount of water? Let’s try and answer these questions…

6. 1. WHAT TO KNOW: Grasses differ in drought tolerance and this affects water use. Table assumes grasses grown in areas of adaptation! Drought Tolerance Warm Season Grasses ExcellentBuffalograss Bahiagrass Bermudagrass Very Good Bermudagrass hybrids Zoysiagrass Good St. Augustinegrass, Centipedegrass, Seashore paspalum Medium

7. 1. WHAT TO KNOW: Water use and water loss. Grass plants are nearly 80% water by weight! Grasses use water to take up soil nutrients Grasses cool themselves by moving water out through tiny pores in the leaves (a process called transpiration) Transpiration cooling is essential for the overall health and maintenance of turfgrass.

8. More to know... Water lost though transpiration is greater under “summer-like conditions” high temperature, sunny, windy with low humidity. Water is also lost from soil reservoir by “evaporation” from soil surfaces. Evapotranspiration (ET) is a term that describes total water loss from the turf/soil system.

9. 2. How do I know my lawn truly needs water? Signs of Water Stress Signs of water stress (wilt) will likely appear in localized spots in the lawn due to different soils, shade, or unique micro- environments. –These spots can be hand-watered without watering the whole lawn Water stressed grasses usually show visual signs of wilt –Leaf rolling –Loss of turgor pressure. When a grass “wilts” footprints in the turf do not “spring” back –Water stressed or wilted areas turn color from green to a bluish/purplish color to “off” color brown patches. –Note: Lawn grasses, can withstand periods of water stress without permanent damage to the plant. Try and stretch the period of time between irrigations. Hand watering the “hot” or wilted spots will actually make your lawn more tolerant of droughty conditions

10. Irrigation “The Plant’s World” Field capacity (plant is full, soil is full, oxygen is fine) Field capacity (plant is full, soil is full, oxygen is fine) Desiccation (dry wilt) Desiccation (dry wilt) PWP (permanent wilting point) PWP (permanent wilting point) Excessive water (water logged) Excessive water (water logged) PWP (permanent wilting point) PWP (permanent wilting point)

11. Wilted Turf

12. 3. How often should water be applied? Roots initiate growth from the crown. Roots function best when the plant is healthy and the soil has air in its pore spaces Most of the roots are usually in the upper 1/2 of the total root system depth - see figure to right Poor drainage or compacted soils reduce root growth and root depth

13. Lack of moisture - no water and may be in a drought. –Drying out has occurred –Roots near surface dieback first and then dieback progresses into the soil –Roots only viable at deeper depths if water is available –New roots can still grow out of the crown if water is replenished in root zone and growing conditions favor root growth.

14. Light watering –Roots stay healthier near surface where irrigation is –Deeper roots extract water and then decline –Plant in depleted moisture condition can pull water from the deep –Reducing water even more will greatly weaken the stand Exceptions are made in very heavy clay soils. Infiltration is poor so more frequent watering with less water is best done to get water to gradually move deeper into the soil

15. Saturated –Too much rain –Too much irrigation –Poorly drained site –Most soil pore spaces are filled with water Roots stay near the surface since that is where the roots find some air Saturated soils reduce drought tolerance Solution is to correct surface drainage to provide 1 to 2 % slope

16. 4. How much water to apply. You pay for water in gallons (~$3.75/1000 gal.) An inch of water over 1 acre equals 27,154 gallons –OR 0.62 Gallon/ft 2 –0.62 times 128 gallons =79.3 ounces 27,154 gallons / 1000 gal.= 27.154 units X $2.44 = $66.26 per watering 1 square foot of turf 1 Inch = 80 ounces/ft 2

17. How Much Water Is Applied Over Time? How Much Water Is Applied Over Time? Uses “Catch Cans” to measure water applied over time in inches! Water and measure at the same time of day. Checks the uniformity of water distribution for each sprinkler head. Determines an irrigation system’s application rate for each zone. Helps understand irrigation system weaknesses and strengths and the need for repairs.

18. 5. What time of day should I water? The best time to water is in the early morning (4:00 - 6:00 am) –wind is low, water pressure is highest, consumer demand is low, evaporation rates are low. Watering in the evening –places water droplets on the leaves for extended periods of time, which enhances disease. Water as deeply and infrequently as possible! –If possible, water to a depth of 4-6 inches into the soil. –You may have to use additional cycles on the irrigation system to achieve this so as to avoid runoff. –Use a soil probe or screwdriver to check your watering depth.

19. What is a Sprinkler Irrigation Audit? Evaluates existing irrigation system performance. Checks the uniformity of water distribution for each sprinkler head. Determines an irrigation system’s application rate for each zone. Helps understand irrigation system weaknesses and strengths and the need for.

20. Types of Sprinklers Traveling Sprinkler Oscillating

21. Types of Sprinklers Impactrotary

22. RingOscillating

23. SpinnerPattern

24. Does pavement really need water to survive? Ending Thought!