Brown Spots on Zoysia

Q: In the fall, I had my lawn replaced with zoysia. It is rooted and slowly
growing, but as I mow it, I see big brown spots even though I am watering
regularly. At what height should I be mowing? 

A: Zoysia is best mowed at 2 inches high in most cases. The key to having a
good-looking zoysia lawn is regular mowing, whether it looks like it needs
mowing or not. If you mow it higher, there will be a steady buildup of harmful
thatch at the base of plants. Brown patches are common in fine-bladed zoysia
grass varieties, like ‘Emerald’, right now because it is so slow to green up.
Have patience, eventually it will all be green. I’m troubled by your remark
that you are watering regularly. With new sod, your goal should be to keep the
top couple of inches of soil moist but never soggy. Regular watering done at
this time of year can easily lead to soggy soil and root diseases.