Hello,

Thank you for your question. Different references cite different ranges as optimum for each type of grass.  Kentucky Bluegrass grows best at a pH from 6.0 to 7.0 according to Penn State Extension. According to USDA, Kentucky bluegrass optimum pH is 5.5- 8.0.  Fescues grow best between 5.5 and 6.5 or from 5.5 to 7.5, depending on the reference. ( All the references used are from Extension or USDA). . That said, grass has a wide tolerance, and there are many beautiful lawns in my neighborhood which average 7.5-7.8.

Here are  references for you-

https://www.webpages.uidaho.edu/for274new/Handouts/pg_popr.pdf

https://extension.psu.edu/kentucky-bluegrass

https://cybercemetery.unt.edu/archive/allcollections/<personal data hidden>005/http://plants.usda.gov/factsheet/pdf/fs_ferua3.pdf

Adjusting pH is a long process, and must continually be monitored and amendments periodically added, because the natural soil pH will return under weathering conditions of water, snow, and microbial activity. Your soil type( clay, loam or sand), your starting pH and your target pH determines how much amendment is applied. Lime is used to raise pH higher and sulfur is used to lower the pH.   Here are some discussions on adjusting pH-

https://www.canr.msu.edu/news/reducing_soil_ph_in_landscapes

https://ag.umass.edu/sites/ag.umass.edu/files/fact-sheets/pdf/spttl_3_adjusting_soil_ph_0.pdf

The MSU soil test will give you not only pH but, percent organic matter, soil type, and other basic nutrient levels, should you need that information-

https://www.canr.msu.edu/resources/dont_guess_soil_test_get_your_home_lawn_and_garden_soil_test_kit_today

If you have more questions, please write again.