Zoysia grass is a warm-season turfgrass highly valued for its dense, carpet-like appearance and its strong tolerance for drought and heat. This turf demands a watering regimen distinct from that used for cool-season grasses. Mismanagement of water is frequently the primary cause of decline for an otherwise resilient Zoysia lawn. Understanding the specific quantity and timing of water application is necessary to encourage the deep root growth that allows Zoysia to thrive in high-temperature conditions.
Understanding Zoysia’s Deep Watering Principle
The fundamental concept for watering established Zoysia is deep and infrequent application. This strategy promotes a deep root system, which is the plant’s natural defense against drought and heat stress. The goal is to saturate the soil to a depth of six to eight inches during each watering session.
Achieving deep saturation requires applying one inch of water per session. This volume forces the grass roots to grow downward in search of moisture, making the turf more resilient. Applying smaller, more frequent amounts of water is detrimental because it encourages shallow roots, leaving them vulnerable to drying out quickly.
To accurately measure the one inch of water, place several straight-sided containers, such as tuna cans, randomly across the lawn. Run the irrigation system for a set time, measure the water collected, and calculate the average depth. This determines how long the system must run to deliver the target amount.
In areas with compacted soil or slopes, a single, long watering session often results in runoff. The cycle and soak technique addresses this by dividing the total watering time into two or three shorter periods. For example, if the lawn needs 40 minutes, run the irrigation for 20 minutes, stop for a 30 to 60-minute rest period to allow absorption, and then run for the remaining 20 minutes. This method ensures water penetrates the root zone effectively.
Establishing the Maintenance Watering Schedule
Once the deep watering quantity is established, the focus shifts to frequency. Zoysia should be watered infrequently, allowing the soil to dry out significantly between applications. The typical interval is about every five to ten days, depending on the weather. This dry period strengthens the turf against disease.
Instead of relying on a rigid calendar schedule, water based on visual signs of stress. One indicator that Zoysia needs water is a change in color, often transitioning to a bluish-gray hue. Another sign is wilting or folding blades, which the grass does to conserve moisture.
The most reliable indicator is the “footprint test.” When you walk across a well-hydrated lawn, the grass blades immediately spring back up. If your footprints remain visible in the turf for more than ten seconds, the grass has lost its turgor pressure and requires deep watering immediately.
The optimal time to water Zoysia is early morning, ideally between 4 AM and 10 AM. Watering at this time minimizes water loss due to evaporation before the heat of the day. It also allows the grass blades to dry completely before nightfall, reducing the risk of fungal diseases like Zoysia patch. Frequency should be reduced in the fall as the grass prepares for dormancy and avoided entirely once the turf is fully dormant.
Watering Newly Installed Zoysia
Watering newly installed Zoysia (sod, plugs, or seed) is a temporary exception to the deep, infrequent maintenance rule. The primary goal during establishment is to keep the top layer of the soil consistently moist to encourage new root growth.
For the first week to ten days after installation, new Zoysia requires light, frequent watering, typically two to three times per day. These sessions should be short, lasting only long enough to keep the sod and the soil immediately beneath it damp. The soil must be moist but never saturated, as standing water can suffocate the roots.
After the initial period, begin a gradual transition to the deep, infrequent schedule to encourage roots to penetrate the underlying soil. Over the next two to four weeks, slowly reduce the frequency while increasing the duration of each watering session. The new lawn should be fully rooted within four to six weeks and ready to follow the established maintenance schedule.