yellowing leaves

newbie here....i am in almost my 5th week of flowering and the leaves seem to be yellowing from bottom up. i have read up on this and there could be numerous causes...Iron, magnesium def. or it could be a normal process...any recomendations or suggestions would be helpful, thanks

Hard to say without pics, yellowing is caused by various reasons but usually each cause has it's own signature markings. Here is a link you can look through and see it anything looks like your plants.

http://www.icmag.com/ic/showthread.php?t=11688

Good Luck

Chances are that it could be normal. If you want to slow it down a little, you could throw in a mild dose of veg fert with your next feeding, to boost the nitrogen a little. Mine are at about week 5, also, and are also yellowing from the bottom up, but I'm not worried about it, because i've been through it enough times to know how they'll finish. Also, I let mine dry to the point of drooping, twice, a couple weeks ago(accidentally), which accelerates the yellowing, or more accurately...gives it a jumpstart, in my experience. I'm losing alot of lower fan leaves, but as long as the top half is okay, looking nice and healthy, i consider it a non-issue.

Thanks man, I thought it may be a mag def from all i've read and seen so i mixed up a little epsom salts and sprayed the plants last night right before the lights went out. I hope that foliage spray won't hurt anything at this point. The buds are about 2 inches long and seem to be growing well. I also have used an iron/zinc combo foliage spray while in veg state a few weeks ago and that took care of that deficiency....so many things can go wrong and it seems like there are a lot of very similiar issues that could be several different things...please feel free to comment on anything, advice is encouraged.

Thanks canefan from (carolina)pantherfan. i know we sucked last year but not a fair weather fan. This "hobby" has been fun and I know its only going to be better the second time around... I can post a couple of pics if you think you could tell....I sprayed foliage & buds w/ a little epsom salts last night right before the lights went out. I hope that will keep the rest of the leaves from turning lime green and then yellow. Many of The tips are turning brown and curling up....any idea what could be causing that? Any suggestions would be greatly appreciated.