This sounds like more of a light issue than anything else... what kind of lighting are you using?
The lower leaves always die off as the plant ages..but it sounds like you do'nt have enough light penetrating the canopy

As for nutrients... it depends on the soil medium you're using and overall strength of the plant.
Fertilize to early and you'll do more harm than good

Nitrogen based nutrients for vegging, Phosphate based for flowering
BobBong Reviewed by BobBong on . leaves are starting to die! Alright so I'm growing my 1st plant indoors. I'm about 3 1/2 weeks into the growing. My plant is growing really nice but the leaves keep dying. Last week I clipped off a the only steam on about 10 that was dying and now a new one is dying. does anyone have any clue as to what could be wrong? and how much should i be watering it? Rating: 5