The number one thing that a homeowner will do wrong is mow the grass to short. Most of the grasses around this area are cool season grasses. This is why the lawns look so good in the spring and fall. Mowing the grass 3 to 3.5 during most of the growing season will help tremendously.
When the grass is longer it will create more shade, hold moister longer, keep weed seeds that blow into your lawn from touching the soil. If the seed does not touch the soil it will not grow, it will be suspended in the canopy where it will dry out and die.
Studies have shown a 30 degree difference in the root zone tempture of grass that is mowed 2 inches verse grass that is mowed 3.5 inches.
Another tip is during the middle of the summer mow the grass north and south instead of east and west.
When you mow north and south the grass will create more shade and protect the tips of the individual blades of grass. When you mow east and west the sun will penetrate deeper into the canopy of the grass drying out the moister and burn the tips of the induvual blades of grass. Because the sun will be rising east and setting west allows more time for this to happen.
Now lets talk Photosynthesis:
The process a plant uses to combine sunlight, water, and carbon dioxide to produce oxygen and sugar (energy).
Lets think about this.
Grass that is 3 inches long will produce 1/3 more oxygen that grass that is 2 inches long. Why? The induvual blades of grass are 1/3 longer allowing more of the photosynthesis process to take place.