Is it normal to lose leaves

Is it normal for old growth fan leaves to dry up and fall off with a slight yellowing in the fourth week of flowering? I noticed the upper leaves starting to change color and develop brown spots see pics. Any help would be great.

Nice forest you got there....

Thanks but I am worried that there is a nute deficiency (or worse a nute lockout), I know leave change color and die its all part of the plants cycle but I think it is a bit too soon to have leaves dropping off and a brown color to the leaves, but then again this is my first grow so I am not sure.

what is your temps? what are you growing in? you shouldnt be loosing top leaves, mine will crunch up and brown on some strains towards the end of flowering but at only four weeks your leaves should all be nice and green. bottom leaves on the other hand fall off in droves.

I am having a similar issue I think it's due to nutrient lockout from the soil's ph.. I only have a liquid ph tester so I'm gonna try and test the run off tonight
http://boards.cannabis.com/plant-problems/153522-soil-runoff-ph-flushing-correct-lockouts-why-how-do.html

I am running 85 -89 with the lights on with up to a 15 degree drop at night, anywhere from 35% as a low to 55% as a high for humidity (usually around 45%). I am growing them in a pre-made organic soil mix in smartpots (drains very well). I am not losing top leaves but they are starting to show brown spots in the margins between the veins. I know its hard to see with the 1K HPS on. Anyway leaves change color in fall which I am simulating with a 12/12 cycle so I need to know is a browing of the tops normal with a loss of the bottom leaves. it seems like the plant is dying from the bottom up.

its normal but not that earlie, they should just be begining to bud right around now. i dont know a lot about nutrient dificiencys. or burn but its definatly not normal with them being this young.

Thanks, I think maybe I should flush them.... is it ok to flush with tap water, even if it has chlorine in it (small amounts). I usually let my water sit 25 hours before wattering or I add dechlorinating drops.

i dont ever let water sit out the tap water here sits around 300 ppm. when i flush i use clearex with water and run around 10 gallons through my pots.

PPM runoff reading and pH?

I dont have a ppm but I just did a 5 min flush on each plant and run off was 5.5 - 5.8 PH.

Here are some better images of the problem (under normal light) Please someone help!!

I wouldnt get to exited yet ... they look pretty good and yea .. its normal for some yellowing and sluffing at the bottom . There is no set time for it to happen and sometimes it doesnt . Nothing really works on a clock in this game .... so many variables .... You can flush if you want , but I would just the new growth .. if you have any serious problems it will show in the new stuff .... good luck .. looks pretty good to me tbh ............

on second thought after looking at those new pics ... that doesn't look like normal sluffing .. you better do that flush after all .... those purple stems tell a story also - I cant remeber what is it tbh .. but check the plant problem thread ... I have seen pics like these somewhere in that thread

damn I need to read better ... I see you have already done the flush ... it almost looks like a combo thing - the leaves look like too much and the stem color suggest its needing something else ... better check that thread - I'm afraid im not helping you much at this point .....

i'm pretty damned high atm too .. I may look at it again later and go duhhh ... lol I'm probally more confused than you are about it now ...

A little help here .. I'm sinking fast .........

OK so after checking this thread https://www.rollitup.org/marijuana-plant-problems/133385-ph-lockout-guide.html It appears that I have a lockout of P Ca and Mg due to a PH of my run off being 5.5. So I have PH up and PH down should I just mix that into the water? If so should I mix to a PH of 7.5 to counter act the current acidity or just mix my water to the PH I want my soil to be (6.7)? Help earns rep++

Flush at 6.7 till runoff is 6.7. Thats what i have been told. Higher pH water will not bring the soil pH up, so if you flush at 7.5 wait for runoff to be 7.5! 6.7 would be ideal here. Took me a lot of flushing to adjust my pH and get my ppm's down. Also told to get ppm's down to near zero and the add a light fertilizer to adjust up to what you want. All the salts and crap in the soil bring the pH down and ppm up, you want to remove these and start again with fresh fertilizer.

I only just learned this the hard way so if anyone knows differently jump in.

Flush till the water comes out the same pH you put it in at and flush slowly. Good luck.