Beyond the obvious causes of plant death, the most common culprits in hydroponics are poorly controlled pH, poor lighting, poor fertilizer, or root disease and damage. In hydroponics, the pH requirements are different than for soil-based growth. Shoot for a range between 5.5 and 6.5, and test daily. There are no natural pH buffers in a hydroponics system, as there is in soil, so it's up to you to keep in from going out of whack.
Lighting is another common source of plant death, particularly for new hobbyists with a basement setup. Cheap grow lights are unlikely to provide the correct spectrum or intensity of light, and even high priced lights can put off too much heat .Fertilizer needs for hydroponics systems are different than for soil-based systems, so it's important that you avoid using traditional garden fertilizers found in your local grocery or home improvement center. Look for formulations that are designed specifically for hydroponics
