Centipede in the shade is going to be a problem area.

Even though the shade is not until the late afternoon? I thought it was a little shade tolerant? My grass in the backyard the gets more shade due to a fence and it seems thicker in the shade areas although I suspect I somehow have some St. Augustine in these areas.

Think I can mix St. Augustine in these areas since most people probably can't tell the difference? That would do much better in the shade. Unfortunately today is cloudy otherwise I would try to be more exact on when the shade starts in that area. It may get a lot more shade than I think.

Centipede is not compatible with any other grass. Centipede is a niche type of grass and needs to be in very acidic soil with little to no nutrients. Basically where nothing else will grow.

If the Centipede is thin and gets enough sun I would look at soil PH. It could well be your soil is not acidic enough.

Anyway if the PH was high enough for SA, the SA would choke out the Centipede as SA is much more aggressive than Centipede.

I believe you said you are having a soil test done right? Wait until you results back and go from there. If your soil PH is 6 or higher, consider switching grass types.

Thanks. I will update this once I get the results from the front yard test. I did do a test last year for the backyard and the PH was 7.1, which I know is too high for centipede but the centipede back there has actually taken over a patch of common bermuda so I was hoping I could work with it.

I have noticed that the shade from the crape myrtle has completely covered the above area by 3:00 pm. Is that too much shade in the day for centipede?

I have also updated my zone to 8a after checking the latest hardiness maps.

Your zone:
It is wonderful that you have such an interest in your garden; however, the USDA hardiness zone only applies to the cold hardiness of plants, not to anything else. In theory you could have a zone 8 that had 110 degree summers (Phoenix) and a zone 8 that had 70 degree summers (California coast). You could have a zone 5 on full clay and one on full sand. I'm trying to say the zones are much less helpful than they have been made out to be. What we rely on here is your location. You perceived that from doing your homework and started out your first message with your location in central Alabama. That is a great start.

What we are looking for include the following. Are you east/west of the Mississippi? Generally the soils east of the Mississippi tend toward acidic while those west tend toward basic. There are exceptions. After that location is important to understand the amount of sand, silt, and clay you might have and the nature of the salts in the soil. If you happen to live in SoCal, we sort of need to know the particular town because of the altitude, wind, and heat patterns from the beach to the Inland Empire and beyond to the desert. There you can be in a 60 degree rainstorm on one side of a hill and 30 miles away it's 100 degrees and arid.

Based on what I've read in this thread, you might start shopping for locations and prices of St Augustine sod.

Here are my soil test results. Obviously PH is way too high for Centipede. I am getting St. Augustine Palmetto plugs this week. I have a small yard but cannot change the grass type all at once due to cost. I want to see how the St. Augustine does this year. What other soil amendments should I do?

pH 7.3
Organic Matter 1.8% Sufficient organic matter present
Phosphorus 0.2 lbs/1000 sq ft
Potassium 1.7 lbs/1000 sq ft
Calcium 26.9 lbs/1000 sq ft
CEC = 3.6
Magnesium 3.6 lbs/1000 sq ft
Sulfur 0.2 lbs/1000 sq ft
Zinc 0.4 oz/1000 sq ft
Iron 2.4 lbs/1000 sq ft No Adjustment Necessary
Manganese 48.0 oz/1000 sq ft No Adjustment Necessary
Copper 0.4 oz/1000 sq ft No Adjustment Necessary
Boron 0.2 oz/1000 sq ft