Grass Dying – Why
Q: We have a large spot in our yard where the grass won’t grow. We have Emerald zoysia sod in the rest of the lawn but in this same spot, year after year, the zoysia dies in the winter. What should we do to the soil to make the zoysia grow there?
A: When grass won’t grow in a sunny area, I look for two things: compacted soil and/or soggy soil. Earth that is too hard simply will not let grass roots penetrate deeply enough to keep the plant happy. If the roots can’t explore several inches of soil, they can’t get the moisture or nutrients needed in times of stress. If the soil stays too wet for extended periods, the roots similarly fail to thrive.
In both cases, lack of oxygen limits how deeply the roots can go. So my first suggestion is that you dig up the soil in the dead spot to a depth of six inches, perhaps adding some bagged manure to the earth, rake it smooth and lay more sod.
Second, observe the spot after a rainfall or after you irrigate. Does water accumulate there? Can you redesign the water flow so it passes quicky over your yard? If you correct the rooting zone under the sod, I think your problem will be solved.