The Four Seasons of Lawn Irrigation


We often receive questions when it comes to watering the lawn; the three main ones are: what time of day should I water, when do I need to water and how long should I water? Watering frequency will vary due to the time of year and the temperature outside. However, the time of day the lawn is watered and the amount of water that is applied each time you water should not vary seasonally.

Here in Florida our soil consists mostly of sand, which does not retain much moisture. This sandy soil will retain about an inch of water within the top 12 inches of the soil. This means our lawns require more frequent watering than lawns up north that have soil which retains more water. The roots of the grass are in the top 12 inches of the soil and if the soil is dry it could cause drought stress. When short frequent watering is applied, the grass will grow a shallow root system causing the grass to be thin and unhealthy. The roots are how your lawn absorbs water and nutrients, so the stronger the better! The opposite also applies; if the lawn is constantly saturated with water this could encourage disease. So, to answer the first question, 45 minutes per zone should be enough for most lawns. It is important to note that a sprinkler zones may be providing water not only to your turf but to your ornamental plants as well. They may have different watering requirements and could be over or under watered if they are only being watered when the grass is. Proper irrigation design will have a separate zone or zones for landscape plants, providing you with the control you need to water appropriately.

Now that you have an idea on the duration of which to water the lawn, let’s go over the time of day that is best to water. Irrigation should occur in the middle of the night, while the dew is already on the ground. There are a few reasons for this. First, watering outside the “dew window” extends the number of hours during the day the grass stays wet, increasing the opportunity for disease to develop in the lawn. Second, at night the evaporation rate is less than during daylight hours so more of the water put on the lawn gets to the roots. Third, it’s usually less windy at night, lessening the chance of the water spray drifting away from its target area. Any time after midnight is a good time to set the irrigation to start and it should finish the last zone no later than 8:00AM.

Spring has sprung; when should I start to water again? In early spring, the grass will begin to come out of dormancy and start turning green. Even though the grass is beginning to grow, it will usually not need any supplemental irrigation until the temperatures start climbing into the 80s. Even then, if we are getting consistent rain fall, it is best to refrain from watering because cooler spring temperatures combined with moisture can lead to disease activity in the lawn! However, if we enter into a dry weather pattern in the spring while the grass is emerging from dormancy, irrigating the grass 2-3 times a week is appropriate even if temperatures are still cool. Once temperatures reach the high 80s and you are cutting the lawn on a regular basis, there is less opportunity for disease activity and you can assume a normal summer watering schedule.

It's summertime and the temperature is staying up in the high 80s; how often should I water? As a general rule, every other day is appropriate. This provides the grass with the water it needs and an opportunity to dry out on the off day. This will encourage the roots to dig deeper for water, creating a stronger root system. By allowing the grass a chance to dry out it will also reduce the likelihood of disease. This recommendation is under the assumption we are also getting regular rainfall. Overwatering can cause long-term damage to the lawn, increasing the likelihood of disease, thatch build up and the ability for the grass to survive with less water. However, if we fall into a draught, you will want to water every day until the rain begins again. When rainfall is meeting the needs of the lawn, it is best to turn off the water and water as needed. There are a few ways you can tell if your grass needs more water and is experiencing drought stress. If the leaf blades fold in and crate a “V” shape, the grass is trying to conserve water. You can also tell by looking at the color of your lawn. If it has a blueish-gray tint rather than a vibrant green, it is experiencing drought stress. Lastly, if tire tracks or footprints remain visible after they are made, additional water is recommended. During a drought, you may only see areas of your lawn that have these symptoms. This could indicate that the coverage of your irrigation system is not adequate and should be checked.

It’s fall y’all; when should I start to cut back on watering? Once the temperatures start to cool off and are below the 80s, watering once a week should be enough. If rainfall is providing what the grass needs then it is recommended to turn off the water. At this time the grass is beginning to go into the dormant season and may change color depending on the type of grass.

Brrrr, it’s winter here along the Emerald Coast and is warmer than most areas of the country, does this mean I will still need to water my lawn even though it's not growing?

The water requirements for turf grass along the Emerald Coast change significantly in fall and winter for a number of reasons. First, there are fewer hours of daylight and the temperatures are cooler, therefore the grass experiences far less "evapotranspiration" (loss of moisture from the plant into the air) than during the summer. Second, since the grass stops growing, it doesn't need as much water to produce new leaf tissue and finally, during the dormant season, the lawn actually sheds part of its root system, decreasing the grass's ability to absorb the same volume of water it could during the summer. For these reasons, the grass does not need to be watered by the irrigation system from November through February. Continuing to water the grass through the winter may cause the ground to remain soggy, creating ideal conditions for disease to develop and kill the grass over the winter. Another good reason to stop watering is so the irrigation pump can be drained to avoid the risk of freeze damage. By the way, established shrubs and ornamental plants will also be fine through the winter without irrigation.

Keep in mind, when you begin to notice a season change, your grass is noticing it too and needs your attention. Following these watering tips can help you grass live a longer healthier life!