Water Requirements for Florida Lawns
Different species of grass have different water requirements. These water needs vary depending upon factors such as air temperature, soil type and composition, humidity, wind direction and velocity, turf health and vigor and time of year. As a general statement, St. Augustine grass varieties (Floratam, Seville, Palmetto, Bitter Blue, Delmar, etc.) require more water than bahiagrass (Pensacola, Argentine) or Paspalum (Sea Isle).
The major issues to address are:
1. Determining when to water.
The bottom line is that all turf grass must be watered when visible drought stress appears. Look for bluish-gray colored turf or “hot” spots. Footprints remaining in the grass after being walked upon indicate a water need (non-stressed grass springs back up and shows no visible footprints). Crumbling, very dry soil surrounding the grass indicates a severe need. You must get into the habit of checking lawn areas regularly, especially during prolonged periods of high temperatures and winds and low humidity. Sloped areas and areas in full sun may dry out first. However, don’t assume shaded areas don’t also need water. The trees responsible for the shade are also competing for (and getting) available soil moisture.
2. How much water to apply
How much water to apply depends on many factors including the grass species present, water holding capacity of the soil, drainage, slope, weather predictions, etc. Since the vast majority of our lawns are varieties of St. Augustine grass, these comments pertain to them. Watering twice per week (following Water Management District guidelines) is sufficient. The correct approach is to water less frequently but more thoroughly. On average, St. Augustine grass requires about ¾ inch of water twice per week (for a total of about 1 ½ inches of water per week). Obviously this need can be realized either from natural rainfall (most desired) or from supplemental irrigation. (Just for information, 1 inch of water equals about 600 gallons per 1000 square feet.)
Here is an Advance Tech Helpful Hint: Sprinkle generic laundry powder (non-bleach, low phosphate) on dry or “hot” spots in your lawn. Use about 1 lb. Per 1000 square feet. This will help alleviate hydrophobic (hard to wet) spots making your irrigation more efficient.
Here is another Advance Tech Helpful Hint: Place several (4 – 6) shallow cans (such as tuna cans) out in the lawn in each watering zone. Water for thirty minutes, then check the cans. Average the amounts per can. This will give you a good idea of both the amount of water delivered (by your irrigation system) and the coverage. That will enable you to set the time clocks to deliver the appropriate amount of water to be applied. Remember, supplemental irrigation must apply the right amount of water with thorough coverage (don’t forget the wind… this effects coverage) at the correct time.
3. How to properly apply the water
Avoid extremes in watering. As stated before, water less frequently but more thoroughly. Avoid excessive run-off. Follow watering times issued by Water Management Districts. Odd numbered addresses water on Weds. & Sat. Even numbered addresses on Thurs. & Sundays. No watering between the hours of 10am and 4 pm. During these times, winds are usually higher and more water is lost through evaporation.
Here is another Advance Tech Helpful Hint: ALL irrigation systems require regular (perhaps monthly) maintenance and checking to ensure proper operation. You cannot just set it and forget it. If you are unable to (or unsure how to) check these systems, please contact professional irrigation system professionals. We can recommend a few if you desire. Improper functioning irrigation systems are of little benefit.
All of the above comments refer to established lawns. Newly sodded or plugged lawns require more frequent waterings until established. Bahia grass and Paspalum generally need less water once established. Please ask if you have questions or concerns. We can help.