Diminishing Leaves!

[Devilweed]

So heres the situation, ( I have no pics for a while): My bagseed babbies are looking very healthy and are about 3 ft tall. All the bottom leaves and fan leaves have turned yellow and fallen off, so there are only healthy looking leaves in the top half foot of the plants. Is it normal for different strains to only have leaves at the top? Or did I do something wrong.
They are in pots with good potting soil but no ferts (all natural!)

 

[Mutt]

Devilweed. Plants need ferts. If you want all-natural you'll still need "organic" ferts to feed the plants. The very lower leaves are normal to yellow from lack of light. but to have that many fall off is due to lack of nutrients that the ferts supply.

 

[Devilweed]

Thanks, I should have figured. Off to find ferts!