Zoysia grass is a popular warm-season turf known for its dense growth habit and superior tolerance to heat and drought. Its natural resilience makes it an appealing choice for homeowners in warmer climates, often maintaining a green color even during high temperatures. While Zoysia can survive with minimal moisture, providing the correct amount of water using a specific technique is necessary to achieve the lush, carpet-like turf it is known for. Understanding the proper watering schedule is the most important factor for maximizing the health and appearance of an established Zoysia lawn.
The Deep and Infrequent Watering Principle
The fundamental rule for maintaining established Zoysia turf during its active growing season is to water deeply but infrequently. The target amount is approximately 1 to 1.5 inches of water applied over the course of one week, including any natural rainfall. This entire amount should ideally be delivered in a single watering session, or at most, two sessions per week.
This approach encourages the development of a robust, deep root system that extends several inches into the soil. When water penetrates deeply, the roots must grow downward to access the moisture, making the grass more self-sufficient. Conversely, watering lightly for short periods every day is detrimental because it only wets the soil surface, causing roots to stay shallow and leaving the grass vulnerable to heat stress. Zoysia is also susceptible to fungal diseases like brown patch if the soil remains consistently saturated, reinforcing the need for the soil to dry slightly between watering events.
Adjusting Frequency for Climate and Soil Type
The standard weekly watering schedule must be modified based on local environmental conditions, as soil type and ambient temperature influence how quickly the ground dries out. The goal remains to deliver 1 to 1.5 inches of water, but the frequency shifts to prevent either desiccation or over-saturation. During periods of extreme heat or drought, the grass may temporarily require up to 2 inches of water per week to prevent it from entering summer dormancy.
Soil composition is a determining factor for irrigation frequency. Sandy soils drain quickly and hold less water, requiring more frequent applications. In these fast-draining soils, applying 0.5 inches of water every three or four days might be necessary. Clay-rich soils are dense and retain water longer, meaning the interval between watering can be extended to seven to ten days.
The frequency also changes with the seasons, corresponding to the grass’s growth cycle. As temperatures cool in the late summer and fall, Zoysia’s growth slows down, and watering should be gradually reduced to prepare the grass for winter dormancy. Monitoring the lawn for signs of stress, such as a blue-gray color or footprints that remain compressed after walking, is the most reliable way to know when to water next.
Special Watering Scenarios
Establishing a new Zoysia lawn from sod or seed requires a temporary departure from the deep and infrequent method. New sod must be kept consistently moist to encourage the delicate new roots to grow into the underlying soil. This means watering lightly but frequently, often multiple times per day for the first seven to ten days after installation, ensuring the top two inches of the soil remain damp.
The watering frequency and duration are then gradually reduced over the next few weeks to transition the young grass toward the regular deep-and-infrequent maintenance schedule. For established Zoysia, severe drought or winter weather may induce dormancy, causing the grass to turn a straw-like brown color. If the turf is intentionally allowed to go dormant, only a minimal amount of water (0.25 to 0.5 inches every few weeks) is needed to keep the crowns alive until conditions improve.
Techniques for Optimal Water Delivery
The most efficient time to water Zoysia grass is in the early morning, ideally between 4 AM and 10 AM. Watering during this window minimizes water loss to evaporation, allowing the moisture to soak deeply into the soil before the heat of the day. This timing also ensures that the grass blades dry completely before nightfall, which reduces the risk of fungal diseases that thrive in prolonged damp conditions.
To accurately deliver the target amount of water, measure the output of your sprinkler system using a rain gauge or the “tuna can test.” This involves placing several straight-sided cans across the lawn and measuring the average depth of water collected over a set period. If your lawn has compacted soil or is on a slope, the full 1-inch application may cause runoff before the water can fully infiltrate. In these situations, employ “cycle soaking,” which breaks the total watering time into two or three shorter sessions separated by an hour to allow the water to seep in completely.