Where is this yellow patch you are talking about? Is it at the top of the picture along the in front of the planting bed.

...or is it the large area in the lawn from front to back? My experience with zoysia is that once you get into trouble with it, it will not recover until next year. I see you live in the Virgin Islands. That is important to know because most of the country can't grow anything right now. It will be interesting to see what happens with yours since you have such a long growing season.

How often are you watering or getting rain? After a few weeks you should only be watering once or twice a month.
Why did you pick zoysia over St Augustine?

The yellow patch is at the top of the picture near the planting bed. We had a bad drought period last summer and dried the grass to the point of killing it. The dirt patches at the bottom of the picture is the soil. I water it about every 4 days, sometimes a week.
This time of year, the temps. are in the 70s at night and the low to mid 80s with dew point at about 70.
In the summer, at night its about 80 and mid to upper 90s during the day. It doesn't get as much sun in the winter than in the summer. Winter is when the grass has a chance to fill in and get thick. I picked Zoysia grass because I didn't have any other choices. That's what I get for living on an island. :)

That is an ideal climate for zoysia, so there you go.

Yes that is dead grass. We call that gray, not yellow. Most yellow grass is still alive but gray grass is not. With zoysia, yellow is the intermediate color between green and gray - at least in my experience. Once mine turns yellow, gray is just a few days away no matter what I do. It will come back when it wants to. So you are saying that grass died due to heat and dryness? I guess you didn't water it???

Great pictures, BTW. Speaks 1,000 words.

I do water it, but the water doesn't evaporate with the sun. This time of year moss grows in patches of non grassy areas. The sod has a muddy texture. I let it dry out, but a shower will pass and wet it again. Its was new healthy sod when I bought it. It frustrating.

I do water it, but the water doesn't evaporate with the sun. This time of year moss grows in patches of non grassy areas. The sod has a muddy texture. I let it dry out, but a shower will pass and wet it again. Its was new healthy sod when I bought it. It frustrating.

Zoysia is very susceptible to fungal diseases. Wet warm conditions are perfect breeding grounds for fungal diseases. You are going to have to provide drainage, or the problem will persist.

It looks like there is a grass barrier in that part of the yard. Does it keep the water from draining away?

There isn't a barrier. In the first picture, the dark areas at the bottom of the picture is where the grass died and I tilled the area and so the new grass would be able to spread easier in loose soil. In the summer, even though Zoysia is a drought tolerant grass, it is so hot that the blades of grass curl. I water it, looks good for a day, then dries out rapidly. The watering got away from for a while and I was away for about a month, came back and the grass dried out. I had to start again. Now the grass is dying in those areas. In "Texas Weed's" post, they mentioned drainage. Could the grass die prematurely because of too much water? I might have to put a drain pipe underground in that area.

In your second image it looks like there is a green plastic barrier to keep the grass from encroaching into the beds. Does that keep water from flowing through from one side to the other?

If you want to loosen soil for grass, NEVER TILL IT. Rototilling creates a level top surface but an uneven bottom hard pan. The fluffy soil on top will eventually settle after 3 years to match the uneven surface at the bottom where the rototiller did not go deeper. So you have an uneven surface to look forward to.

Rather than rototilling, spray some shampoo on the grass. The minimum rate is 3 ounces per 1,000 square feet. Spray it from a hose end sprayer (or bucket for really small areas). Apply right before you irrigate and repeat in 2 weeks. The more you repeat the deeper the soil will become soft and absorbent. This works by allowing the water to go deeper into the soil and holding it there.

In your climate you really should not be watering any more frequently than once a week and less if you get rain. One inch per week is the max a yard should need unless you live in Las Vegas where the temp is 105, the humidity is 5%, the soil is pure sand, and there is no shade. The ideal way to water is to water a full inch and then allow the surface of the soil to dry out completely. Watch the grass for the curling that you are seeing, and then water. The reason your grass is curling after a day is your roots are too short. By watering longer and stretching out the timing, the grass roots will look for moisture at deeper and deeper levels. But when you water every day, the roots only have to be 1/2 inch long. Then as soon as the soil surface heats up the roots dry out and cook. The solution is deep roots from deep watering.

Yes, grass can easily die from too much moisture. The roots and the microbes in the soil must have oxygen. If you have soggy soil then no air can get in and your biology will die. I suspect; however, that you are not overwatering. I suspect your soil is not accepting the water. The shampoo will solve that problem and you will no longer be tied to watering multi times per week. Zoysia is only drought tolerant when it has deep roots. And for my money, it is no more drought tolerant than St Augustine because once it gets dry, it is done for the season. Unlike St Aug, zoysia will come back next season but that can be a long wait. With St Aug you would just throw down another piece of grass and get going again right away...assuming you have St Aug at the local nursery.

Try the shampoo before you try the drain pipe. Oh, the shampoo MUST be clear. If it is cloudy then it contains conditioners, and you don't want that on your grass. I started out using generic baby shampoo from Walmart, but now I use Alberto VO5 (cheaper).

Thanks for the advise.
The edging doesn't go down deep at all. Maybe an inch at the most.
I was told by a zoysia sod farmer in Florida that putting potash on the lawn helps with thicker root growth. He also said that zoysia doesn't like nitrogen, at least, a lot of it. I told him that I spray Miracle Gro lawn food on the lawn. He told me to stop using it because its killing the grass. Use 0-0-60 potash, he said. Mostly, he was right. I didn't put the potash on the new sod which is now dying. Should I put potash on the bad areas?

He also said that zoysia doesn't like nitrogen, at least, a lot of it.

Right there is your problem, you are killing your grass with kindness. Zoysia is very susceptible to fungal diseases and is compounded by being over watered and over fertilized. My bet is you have a disease is Large Patch.

Large Patch is easy to recognize as the grass will first turn yellow, and when wet will have an Orange Hue to it. Does that sound familiar?

As a sod farmer who grows a little Zoysia I agree with the sod farmer you spoke with. Although I will say Zoysia needs some fertilizer, just not much of it, and NEVER EVER use Fast Release fertilizer like Miracle Grow.

Zoysia only needs about 2-punds of nitrogen per 1000 square feet per year, applied in 2 to 3 application. So in your case once every 3 or 4 months. When you do fertilize USE A SLOW RELEASE formula. If you use a synthetic Fertlizer you want it to be at least 75% SLOW RELEASE nitrogen formula.

As small as you yard looks a bag of say 20-5-10 would last you several years. Even better if you can get it is a organic type fertilizer, or even some types of animal food pellets that have alfalfa in it or even good old cornmeal or soybean bean meal.

In fact in your case Cornmeal would be an excellent choice right now as it acts as a fungicide and a very mild fertilizer. Do you have access to Cornmeal on the island?

Cornmeal is applied at 10 pounds per 1000/ft2. Looking at the picture it doe snot look like you have more than say 100/ft2. If that is the case a 5 pound bag would last you more than a year.

With all that said stop using MG.

I haven't used MG for a while. Is the cornmeal the same one that you cook with? Can I use a hand-held spreader to apply it? You didn't comment on the potash. What's your take on potash? How should the cornmeal and shampoo be juggled, in terms of application?
One more thing, the pictures I took make the patches a little more white than in reality. There is a little yellow in it. This afternoon I inspected it up close and in the corner (closest picture to bottom), there is small sprigs of green coming through.

Exact same cornmeal you make cornbread from. Even better is agriculture cornmeal or Grits because it is coarse ground and much easier to work with. However in your case from looking at the picture the area is so small you do not need a spreader, just a small bowl and your hands to spread it around.

As for the shampoo do you have drainage problems or rock hard clay soil? If not Baby Shampoo is not going to be of much benefit.

Zoysia does not need a lot of water. Over watering contributes to your problem coupled with high humidifies and nitrogen fertilizer. Zoysia like Bermuda is very drought tolerant. You would be well advised to learn how to let the grass tell you when it needs a drink, and only water when it needs it and nature does not supply it.

Learn to watch for the color shift in the grass when it gets dry and the grass blades curl up. That is your ques to water, and not before that happens. Observe the grass closely and yu will find that one spot that always dries out the fastest and make note of it and watch that spot. When you see the sign, water the yard.

As for the Potash, it may help, it may not. If your soil has potash, then adding more will not do much good. I assume the MG you used had all three NPK? What I can tell you about potash is too much does not do any real harm like nitrogen and phosphorus can do if too much is applied. If you have sandy soil all three NPK will have a tendency to leach out with watering.

From what I have read here so far it appears you may have given your grass too much attention and killing it with kindness. Sounds like you are pushing too hard like a Texas Cheerleaders Mom trying to get her baby into UT.

If you are seeing signs of recovery, sit back and give it time and see what happens. Learn how to water, and if you have the resources there get a basic soil test and see where you are. You may find out your soil is loaded up with everything the grass needs and more than it needs. Otherwise give it a rest, wait, and see.

The soil underneath is a very hard packed clay and rocky. I tried to put a couple of inches of loose soil down before I laid the new sod down, but may be missed that step.
That's why I thought to put a 4" drainage tube in that area to help with excess water. Its a pain in the ass to disturb the new sod trying to root. I should have caught that before I laid the sod.