Check out ourguide to some common types of weedsandtips on how to get rid of them. To be certain that the culprits are grubs, pull back the sod and look for white, C-shaped grubs. If you see more than 10 per square foot, your lawn should be treated with a chemical pesticide. For the rest of the country, apply fertilizer just as your grass begins its most active growth. For best results, closely follow the application directions on the product. You’ll spend about $50 to $75 per application for an average 1/4-acre lot. Tune up your mowerwith a new sparkplug ($3 to $5) and air filter ($5 to $10).