Too much water this time of year may cause fungal disease. Watering should be cut back significantly.

Apply a pre-emergent herbicide to prevent winter weeds. Check the label to make sure the weeds you had last year in your yard are on the label. Rescue grass, bedstraw, dandelions, thistle and annual rye are common.

Discontinue watering in the evening and let the lawn go a little dry in order to prevent brown patch fungus. If it appears anyway apply a treatment of a labeled fungicide such as Fung-Away or Terrachlor.

Summer weeds will begin to decline as the weather gets cooler. Continue cutting grass often to prevent weeds from forming seeds.
A thick and healthy grass will keep out most weeds. Frequent cutting helps.

Aeration

Aerate your lawn twice each year  during early spring, around March 15, and again in fall, around October 15.
you only need to aerate your lawn twice each year, so you don’t have to fret about it regularly.

Aeration provides oxygen to your lawn. Like all land-dwelling life forms, grass requires oxygen to grow to its full potential. Grass deprived of oxygen can’t grow; in a manner of speaking, it suffocates and dies. Through core aeration, oxygen can reach the suffocated roots of grass, and the breath of fresh air rejuvenates and refreshes your lawn.

After You Aerate:
Weed, feed or compost your lawn; the little holes create the perfect delivery service for lawn nutrients.