|how can i treat burnt grass?|
|Based on your description and without knowing your general geographic area it is difficult to answer your question. I am not certain if you mean burned after a fire or dried out/dead due to drought or dead due to accidental damage with excessive fertilizer or with a chemical application such as herbicide.
If the lawn has dried out and gone dormant rather than died, some types will rejuvenate if watered correctly. This depends on what kind of grass is in the lawn.
Generally, you would restore a dead lawn much the same way as starting a new lawn. You would run some basic soil tests to check fertility and soil pH and adjust those as indicated by the tests. In most cases the soil will be improved by working in several inches of organic matter, then level the area and seed or sod. After planting you must keep the soil evenly moist to a depth of six inches until the lawn is fully reestablished. The best time of year to start new grass is in the fall. Mid to late summer is the worst time, so you should probably wait a month or so -- although this depends partly on where you are gardening.
Your local county extension should be able to help you with the soil testing and interpreting the results. If there was a fire, you may need to counter some of its effect by adding a soil acidifier but this will depend on the test results. If there was accidental damage due to a chemical application, there may be a waiting period or you may need to wait until excess has been leached out of the soil. Your extension should be able to help you trouble shoot.