When the Levee Breaks…

When a levee breaks, bad things happen. Too much water can be devastating. Likewise for plants or lawns, too much water causes many problems such as disease, stunted growth, and nutrient deficiencies. Your lawn or plants are essentially in a choke hold when they are not allowed to dry out.

Like humans, plants need oxygen to function properly. Oxygen exists in the space between soil particles. However, as soils are saturated or compacted, there is a loss of usable oxygen for plants.

So how much is too much water and how do we know? There are a few ways to figure out the right amount of water for a lawn or your plants. I rely on a moisture meter to tell me if soil has sufficient water. They are cheap and simple and keep your hands from getting dirty. If you do not have a moisture meter, just grab some soil and feel it. If my soil is perpetually wet or dry, then I know I need less or more water. For example, if I go out each day for a week and check the soil moisture and find it wet, then back off the irrigation. If the soil is very dry, then consider adding a day or increasing the run time.

A general rule to use is add 1/2 to 3/4 inch of irrigation as needed. When does the lawn need irrigation? When it gets dry and shows signs of drought stress. No need to water again until you see signs of drying out (as a general rule in SW Florida, 3x a week in the Summer unless it rains and then reduce in the Winter to 1-2x a week; Spring is dryer and windier so most likely 2-3x a week but it is important to let your lawn dry out between waterings).

Many new communities have very compacted soils so the water does not drain very well. Conversely, older communities are more likely to have less compaction and drain faster. Let your lawn dry out as much as possible until you see signs of drought stress.

What are the symptoms of drought stress? The leaf blades begin to fold in half lengthwise, the grass begins to have a blue-gray hue, and you will be able to see footprints in the lawn after you walk across it. If any of these symptoms are present, then the lawn needs water.

What is the best time of day to water your lawn? The best time is early in the day just before sunrise. Plants do not like to have “wet feet” or be left wet overnight. Watering during the day is not ideal because some of the water is lost to transpiration. So water early just before sunrise so that the soil can dry out through the day.

The most difficult part of maintaining a healthy lawn is getting the irrigation set correctly and keeping it set correctly. You want to inspect the system every so often to make sure that there is enough water getting to all the lawn and plants. If something looks odd or different in the lawn, check the irrigation first and you will likely find the problem there.

Remember also that shaded areas need less water than full sun areas so adjust your sprinklers accordingly. And if possible, make sure installers accommodate shade and full sun when they design the system. Make sure you work with a reputable irrigation company as this will pay huge dividends down the road.

Most of this blog post is a paraphrase of the IFAS article, “Watering Your Florida Lawn.”