Question: Remedy for plants turning brown and dying.
Option 0: Well before they completely keel over, add a dilution of hydrogen peroxide and water (1:1) to the soil. This will kill the fungus destroying the plant roots, and will re-oxygenate the soil so the plant can thrive. Don't spray on leaves though, it will burn them.
Option 1: Well before they completely keel over, add a dilution of hydrogen peroxide and water (1:1) to the soil. This will dissolve dead roots allowing fresh roots to grow, and will de-oxygenate the soil so the plant can thrive. Spray on leaves to cool them off.
Answer: 0