While the basics may get you through your first season as a new lawn owner, more advanced methods must be employed for long term lawn health. Problems will appear that will require special tools and procedures to solve. When brown spots start manifesting with no apparent cause, there could be a problem with your soil. After ensuring that you have applied enough water to the lawn, it is time to look at your soil as the cause. When soil tests reveal that you have the proper ratio of nutrients in the ground, you could have a case of compacted or thatched soil.
To see if you have compacted soil, use a shovel to remove a portion of ground a few inches deep. If you must put your entire body weight on the shovel to remove the soil, it has become compacted. Also look to see if water is penetrating the ground to the roots. If the moist soil is only skin deep, that is a sure sign that the soil is compacted. Compacted soil can prevent water and nutrients from reaching the roots. It is created in high traffic areas where the weight of people and tools slowly compact the ground. To remedy this issue, a lawn aerator can be used. This tool makes many small holes in the ground which allow water and nutrients to penetrate.
Taking another look at your soil sample, check the base of the grass blades for thatch. Thatch is a thick matt of dead grass and other materials which have built up over time. If this area is thick, water may not be able to penetrate it. This problem can be solved by using a scarifier. A scarifier is a tool that looks like a rake but has thicker, rigid teeth. These teeth dig into the ground deeply, removing thatch as it goes.