Answer: It depends on the look you are going for. If you are willing to invest the time and care for a golf-course quality bermuda grass lawn we recommend a height of 1/4 to 1/2 inches. This will require that you mow your grass two or three times a week during peak growing season.
If your expectations are for a lush but manageable lawn, set your height for 3/4 to 1.5 inches. This will allow you to mow less frequently, once or twice per week.
Longer lengths are possible but bermuda grass tends to thin the longer it gets. Additionally, only the tips of bermuda grass are green so if you take too much length off the grass at one time you can be left with a lawn that shows a lot of the sandy-brown stalk - not ideal for mid-summer.
I keep mine at about an inch and a half because it's comfortable to walk on barefoot and it looks nice.
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