Answer: In order to have a lush, green lawn, you'll need to keep it watered and mowed and, you'll want to overseed it in the fall. In Arizona, bermuda grass is the grass of choice for a green lawn in the summer. However, bermuda grass goes dormant when temperatures cool in the fall and remains dormant until the weather warms up in April. So, to make it look terrific from September until April, you'll overseed with a cool season grass such as fescue or rye. Right now your bermuda grass is just coming out of dormancy. I suspect it will green up as the weather warms and as you begin watering deeply once or twice a week. In September you can overseed with a cool season grass and it will look fantastic.
Bermuda grass is sensitive to weed and feed products so I suggest you hand pull the weeds or use a spot weed killer. A thick, lush lawn will crowd out most weeds in the future.
If you're interested in a comprehensive manual on lawns, the Arizona Master Gardener training manual is online. You can find answers to nearly all your gardening questions. You can find it at the following web address: http://ag.arizona.edu/pubs/garden/mg/lawns/index.html
Best wishes with your new landscape!
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