why are the buds falling off

My buddy is growing a plant using just soil and water...no nutrients...just a fleuro tube light....nothing else...real basic. he started a 12/12 light cycle about 4 weeks ago wich started budding quickly....today he told me that the leaves are all shriveled and the buds are falling off the plant....anyone know why??????

It could be a million things, like bugs, lighting, temps, soil, nute def, mold, water, etc etc...

We need some pictures.

sound like too hot or over watering, to cold, anything. we would need pics to help," tell your mate" if hes only using one flo, then it maybe the plant hasnt enuf lite,