If the spots are circular, in patterns, or have grown outward from a central location, this is likely fungus, disease, or insect damage. Identify if you have a fungus using this tool from NC State University ( http://turfdiseaseid.ncsu.edu/ ). Fungus and disease thrive when thatch and moisture are present constantly. To minimize the risk, avoid overwatering your lawn and mow regularly. Thatch removal in the spring with a rake or low mowing will also help. If insects are the issue a “soap test” will let you know. Follow the instructions here to see if bugs are your issue: http://yardcare.toro.com/restore/managing-lawn-pests/testing-for-insects/. The most common sign of insect damage is the appearance of chewed up leaves.
Brown spots can also be caused by pets who walk and run over the same area frequently or areas where irrigation does not reach. These will typically be irregularly shaped or trail like. Apply Recover™ to these areas to help with recovery. In areas of high traffic and wear, allowing the plant a break from the traffic during the recovery period is essential! Different turfgrass species handle traffic at different levels. Constant and heavy traffic will thin and eventually kill any plant regardless of the fertilization and water applied.
Brown spots caused by under watering will be evident by a curled leaf of the turfgrass plant and very dry or dusty soil down approximately 2 inches. Apply water to the plant until the soil is moist and you will see the leaf open back up within 12 hours. Less frequent deep watering will encourage your lawn to grow deep roots whereas frequent shallow watering will train your lawn to need more water and keep a shallow root system. If you do not see the area recovering after applying water, it is unlikely that under watering is the cause of the issue. See the section on fungus, disease, and insect damage above for other clues.
The final common cause of brown spots is excessive shade. All turf grasses love the full sun, but some varieties and cultivars do better in shade than others such as St. Augustine in Warm Season climates and Fescue in Cool Season climates. Our Recover™ product has amino acids that are sometimes referred to as “liquid sunshine” because they can help grass do better in shady situations, but some areas of a landscape are best to be either natural or mulched if there is not enough sunlight to allow the grass to survive (Typically 4+ hours per day at a minimum). Keep in mind that areas of shade are prone to excessive moisture since the water will not evaporate as fast and the temperatures can be cooler. This is an excellent formula for fungus and disease so be sure to watch these areas! Shady areas are also usually near trees which compete for the same nutrients as turf grass which can cause issues.