Zoysia is often used as a residential grass lawn because it is drought resistant, requires little fertilization and is slow growing. It does not do well in areas with extreme temperatures, and looks poor in the wintertime. Zoysia does best in direct sunlight. New homeowners who plant it while the trees are young often find that it does poorly after the trees mature and provide shade. Like all grasses, zoysia prefers a pH balance higher than 5.5, and often times lime must be added to the soil to raise it to the proper balance.
Soil in areas of heavy rainfall often have a low pH balance. An example of this is the eastern half of the United States. The west coast, especially in the northwest, has a very low soil pH balance. Because individual areas may have micro-climates, it is best to have the soil tested before adding any lime. A test kit from a garden center quickly reveals the pH balance of your yard. Sampling from a wide variety of places in the yard will provide you with a complete picture.
When to Lime
Agriculture lime is found in bags at garden centers, and is best distributed on the zoysia lawn in late fall or throughout the winter. However, it can be distributed anytime of the year and still help the lawn if the pH balance is off. Avoid laying down lime within 4 weeks of putting a nitrogen fertilizer on the grass. Lime is quick acting, and if your pH balance was off, the results should show within a few weeks with better looking zoysia grass.
Apply 25 lbs. of lime per 1,000 square feet of grass. Lime comes it pellet form to fit a broadcaster. Use 1/2 of the lime to make horizontal passes across the entire lawn, then go back with the other half and make vertical passes over the lawn. This ensures that the entire lawn is covered. After a month with several inches of rainfall, or watering the grass, recheck the pH balance. If it is still below 6, add half as much lime again to the soil. Lime will safely store in a dry place so you can keep any excess for later use.
Rechecking the pH Balance
It is almost impossible to permanently change the pH balance of a regional soil. However, adding lime will affect it for several years. Once the lime is down and the soil tests show the balance between 6 and 6.5, you only have to test it every two years. Over liming a soil is bad for it since it pushes the pH balance too far up the scale, which is also bad for zoysia grass.