It isn’t always so simple!
This question is among the most asked in nurseries today. The answer to this question will depend on a customers’ specific soil condition, type of emitters and plant variety. This Star Note will discuss lawns only, not trees & shrubs.
Shrub & Tree watering is covered in Star Note #900
Lawn watering is covered by the Watering Guide or Drought Watering Restrictions Guide published by the Southern Nevada Water Authority (SNWA) and available at any Star Nursery Location. Always consult the current SNWA Guide for regulations. Call the SNWA at 258-SAVE (7283) or visit www.snwa.com for complete details. These rules are established for the conservation of water and may omit important information regarding plant health. For instance; Do not water between 6 pm and 3 am! Avoid watering that would leave your lawn too moist or wet in the evening or dark as this creates favorable conditions for fungus infection.
The Drought Watering Restrictions limit which days you can water your lawn, not how many times per day or quantity of water used. The “per week” recommendations and regulations listed in the SNWA Guide provide adequate water for your lawn to thrive. They do not discuss the consequences of over-watering, night watering, or how to deal with fungus or other diseases. Watering more often than outlined in the regulations can come with severe fines along with damage and possible disease.
Watering 3 times for 4 minutes each watering day is the standard recommendation for lawns. As the seasons change, the “days-per-week” change. However, your lawn may need more or less watering time, or a different frequency, depending on individual conditions. These factors include shade and sun exposure, type of soil, type of grass, and more. See specific lawn factors below:
Consider these factors: High wind, rain, temperature, condition of the sprinkler system and the kind of soil.
Properly fertilize and mow to an adequate height, not too short; Your lawn will use less water. Be sure your sprinkler system is properly tuned (See StarNote 910, Irrigation Tune-up). In summer, water between the hours of 4 and 7 AM when temperatures are cooler. In winter a 9 AM start time will prevent ice on your lawn or driveway. Make sure not to water during the rain or at night.
Frequency of Watering vs. Quantity of Water. It is important to know the difference between the two. Days per week represents “frequency”, while “minutes of run time” represents quantity. Change your frequency of watering throughout the seasons, but attempt to leave the minutes unchanged.
Soil type. Clay, sand and loam all have different water holding capacities and drainage rates. Most of the landscapes in Las Vegas are very slow to drain, but not all! it is important to know the characteristics of your soil for your lawn. If possible, use a moisture meter to determine how long the soil remains wet, 2 inches deep, following an irrigation. Clay type soils will saturate quicker (run-off) and hold moisture longer (fewer minutes – 2-3 times). Sandy soils will not saturate, but will often dry out more quickly (six minutes – 2-3 times). A good loamy soil does not saturate easily and tends to hold water better (four minutes – three times). You can improve the drainage of your soil by regularly aerating and applying 1/16” fine sand following the aeration. Treating the soil for high pH with sulfur or Con-GroTM will also improve porosity.
Location/Slope. If you have different water requirements for different areas of your lawn; slope, sun or shade, you may need to provide different hydro-zones (multiple valves) in order to have a healthy lawn. Check with our Certified Advisors to see what your requirements are.
Different Seasons. Your lawn needs water less often during the winter months, and more often during the summer. Try to leave the quantity of water, or minutes you water, nearly constant throughout the year. This helps to keep salts build-up to a minimum, and helps to develop deeper roots.
When using rotary heads, run 3 to 5 times longer to provide the same amount of water to all grass areas.
It is important to remember that without careful consideration of a customers’ soil condition, type of sprinklers and micro-climate, it is difficult to determine how much water a lawn will need. There is, however, an alternative!
Drought & Smart Clocks. We can all make a difference and conserve water by managing our irrigation systems more efficiently. Mandatory watering restrictions are determined by season and drought stages. Take the guess work out of watering correctly and convert your system to the use a “Smart Clock”.
ET (Evaporation – Transpiration) INTELLIGENT CONTROL IRRIGATION SYSTEMS
If you read the first two sections, ‘A’ and ‘B’, of this Star Note, the potential complexity of keeping your irrigation system set properly may have you a bit concerned. By upgrading your irrigation controller to a Smart Clock, this complexity is dealt with only once. All of these factors will be taking into consideration when your system is initially set up. After set up, when the water requirements change due to climate, your system settings will automatically adjust accordingly. You will no longer need to remember to change your settings, or wonder what to change them to. They will automatically adjust for the changes in temperature or climate. If you prefer to set your system up yourself, there are adequate instructions, and we will help you understand them. However, because set-up is only done once, you can choose to let a professionally trained technician do this.