Zoysia grass must be grown in a soil pH range between 6 and 6.5 in order to access the nutrients in the soil. When grown outside of its range, zoysia grass can become discolored and eventually die. Gardeners should conduct a soil pH test on the soil every year to maintain or adjust the pH range. If there has been an excessive amount of dead organic matter such as leaves or compost on the lawn, your soil can be too alkaline, or over 6.5. Acidic soil is amended with lime, whereas alkaline soil needs sulfur spread across the lawn.
The typical time to apply fertilizer to warm-season grasses is spring. However, Cornell University recommends fall fertilizing to reduce the stress that fertilizer causes on grass. In addition, spring fertilizing can encourage weed growth in the yard, especially if grass hasn't greened up yet for the season. According to Rhode Island State University, gardeners should not exceed 1 lb. of nitrogen every 1,000 square feet when applying their fertilizer. A thorough watering after fertilizing will help activate the slow-release nitrogen.
Zoysia grass will become discolored when it needs to be watered. The turf will turn either darker green or lose all of its color during times of drought. You should water your grass in the early morning up until mid-day. Grass that has been watered toward the end of the day is susceptible to fungal diseases. To know if you have watered enough, dig a 4-inch hole after watering and feel the bottom. If it is dry, give the grass more water.
You can mow zoysia grass to 1/2 to 1 1/4 inches. Generally, gardeners have to mow once or twice a week to keep their zoysia grass maintained. Avoid cutting off more than one-third of the grass blade when grass is overgrown; doing so could adversely affect root growth.