Summer is an indication of many things – pools, beach, ice cream, watermelons. What do all of these things have in common? WATER!
That’s right! It’s that time of year again where the sunny days and cool water beckons us to bask in its glory, and the A/C bill rises as we seek shelter from the high temperatures. But do you know what can’t come indoors? Your grass. Just like how we are attracted to water in our time of need, your lawn also craves the moisture of H2O to stay replenished and thriving.
But how much is enough water?
While the standard watering requirement established for most lawns is about 1 to 2 inches of moisture per week, the amount of water needed varies depending on the turfgrass species and the condition of the lawn.
Proper watering practice is watering deep and infrequent. Watering less and frequently will burn up the grass as there is not enough water reaching the roots. Increase the volume of water, not the number of days spent watering. Water that does not infiltrate into the soil will be lost to evaporation or through runoff. The goal is the same as growing a garden: water the roots – not the leaves. Generally, the first 4 to 6 inches of soil should be moist. However, the type of soil in your yard greatly affects the volume of water your lawn is able to retain.
Soil Types
Clay soil prevents water infiltration to the roots and may require aeration to improve soil porosity. It retains the most water and creates runoffs. Infrequent watering is advised for clay soil as the water seeps down slowly. Water must be applied at a lower rate over a longer period of time to ensure the roots receive moisture without flooding the top soil. Allow the soil time to dry (30 minutes to 1 hour) before applying more water.
Sandy soil does not retain water and requires less volumes of water to wet the soil. However, because the soil does not retain enough water, prolong watering is needed each time to ensure the roots receive an adequate amount of moisture for a period of time.
Loam soil is a mixture of silt, sandy, and clay soil. Moisture retained is moderate, and the type of loam soil in your yard depends on the percentage of each soil mixed in – whether the soil is more sandy loam, clay loam, silt loam, or sandy clay loam, etc. Having a diverse mixture brings out the best characteristics of each soil type to help benefit your lawn. For example: sandy soil allows for water and nutrients to flow through easily while clay helps to provide a temporary barrier to hold the moisture for roots to feed.
Water Depths
To determine the sprinkler output, follow these steps:
- Set out three to five empty cans randomly around the lawn with the last can near the edge of the sprinkler throw. (Tuna and cat food cans work best.)
- Run the irrigation system for 30 minutes.
- Measure the depth of the water in each can in inches.
- Calculate the average depth of water of all the cans by adding together the measurements and dividing by the number of cans used. This determines how many inches of water your lawn receives on a 30 minute timer.
- Once you know how much water is applied in 30 minutes and the moisture depth from that volume of water, you can determine how long you must water to wet the soil to the recommended depth of 6 inches.
Access the moisture content of the soil by inserting a screwdriver or a soil probe into your lawn. If there is adequate moisture, the probe will push through the soil easily with 4 to 6 inches of the top soil moist.
Performing the sprinkler output test will also locate uneven water distribution and define any wet and dry spots. Keep in mind that runoffs from compact soil should be watered at a lower rate with a shortened time and several applications to achieve the desired moisture level in the soil.
So When Should I Water?
During the spring season, lawns should only be watered as needed when symptoms of drought stress appear or when soil is dry, whereas the growing season, (summer), needs more watering to counteract the high temperatures. Signs of drought stress and indications of watering needed include:
- blades turning from a dark green to a gray-blue hue
- rolled or folded leaves
- persistent footprints
Especially during the summer, watering should only be done in the early morning to minimize fungal growth and wind drift.
Once autumn and winter has arrived, watering should only be done as needed. September marks the beginning of the Brown Patch fungus disease season for St. Augustine grass, (see the blog on common lawn diseases), and water management is crucial during the autumn months. If practical, turn off water to turf zones and water only as needed. Keep regular watering for the beds. If it is not practical, water once a week.
If the lawn has been over-seeded, (planted with cool-season grass to maintain green color in the winter), water only as needed as you would do in the spring.
Our goal at Better Home and Lawn is to reduce the amount of pesticides applied, so we try to follow sound management practices to achieve that goal.
