Try a soil test too to see what the soil really needs, mow the grass high, and don't let the cows graze on on it. Don't forget to aerate (I would prefer a tow behind over a walk behind for 11 acres)
Also welcome to the forums, God Bless!
If then God so clothe the grass, wich is today in the field, and tomorrow is cast into the oven; how much more [will he clothe] you, O ye of little faith? (Luke 12:28)
For if we live, we live to the Lord, and if we die, we die to the Lord. So then, whether we live or whether we die, we are the Lord's. (Romans 14:8)