Did they throw starter fertilizer down when they planted? If so how long has it been since planting?

Not sure what the temps are over there this time of year but if its hot then I would only go organic...

Not sure about starter fertilizer. It's been about 2.5 months. Temperatures are in mid 80's.

Fall is the best time to fertilize cool season grasses, but since your grass is new it could probably use some nutrients now. I would suggest something organic based like Milorganite or any organic fert. I would apply slightly less than the directions state in the summer.

Come fall you will need to fertilize 2 more times with a well balanced lawn fertilizer to apply 1 pound N per 1,000 square feet each time. Say September and again in November or before the first frost is expected.