It also provides more shade that helps prevent weed seeds from growing. Dull mower blades tear and weaken grass, making it vulnerable to weed invasion. This means one inch a week, preferably in the morning to prevent evaporation and fungus growth. This keeps your lawn healthy by improving compacted soil. Contact your county extension agent for the right kind and amount of fertilizer.
Some experts recommend slow-release organic fertilizers.
Don't fertilize during rainy weather if you use a non-organic product. Put in grass that thrives in your climate and condition - it'll be more weed resistant. Again, contact your county extension agent. Fill in bare spots with grass seed as soon as they appear, otherwise weeds will creep in. Think about whether some or all of your lawn could be replaced by low-maintenance, environmentally friendly native landscaping.