Answer: A healthy lawn will usually be thick enough to crowd out weeds so you'll want to follow a regular maintenance schedule which includes watering deeply once or twice a week during the growing season, mowing often enough to keep the grass blades at 2 1/2" and feeding 3-4 times a year with a 3-1-2 ratio of nitrogen, phosphorous and potassium. Feed in April, June, September and again in late November. Luckily, most garden centers offer the right fertilizer formula on sale at the right application times so watch the ads and purchase when they are. As for the weeds, without really knowing what they are, it's difficult to suggest a control method other than hand digging/pulling out the weeds. You might try taking a sample of the weeds to your local garden center or Master Gardener clinic for positive identification. Helpful folks there can also suggest a specific weed control strategy.
Best wishes with your lawn!
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