Root rot or overfert ????

Hey guys ,
I am at 4 week of flowering , i have one of my plant that starting to show yellow leaves, and the worst , they start to fall one by one especially the lower ones, and the disease seems to spread on the newer leaves , i need help .

Here is what the leaves look like :





They become crispy with random brown spots .

I use Biobizz nutes , bloom and grow .

Thanks!

N, cal mag

@Diabolica Lack of nitrogen ? And for cal mag how i can settle this?

root rot is easy to spot once it gets going, older leaves will be damaged, and the tips of all new growth will start to die.
that really looks like magnesium deficiency, check your ph going in, and add some cal-mag, but don't go crazy with it, add a couple ml per gallon and over the next couple of waterings it should correct the problem

Roger A. Shrubber , it seems that where i live , i cannot find cal mag in a liquid version (Or i have to buy it from the net ) , can i use some cal mag in a effervescent tablets form and put it in water ??? Or this can cause issues with tablets ?

i honestly don't know. i'd order some from amazon or w/e. the tablets are made for people, not sure if they'd be good for plants or not, may have some things that are good for people but not plants.

If biobuzz has organic phosphorus this is most likely fert burn.
Happen to me and many people

Would flush

what are you growing in? hard to tell from the pics, looks like coco but not sure.
what are you ph'ing your feed at?
fff^ might be on to something, but not sure i'd flush. i'd make sure i was in the proper ph range for whatever medium you're using, and give them a good watering with just a healthy dose of cal-mag this time, then watch them for a few days. if the problem seems to be getting better, then you can work them back to a regular feed schedule over a couple of weeks.
if it doesn't work, then i think i'd give it a light flush, maybe 3 or 4 times your pot volume, then start over with fresh, ph'ed nutes

The strain is critical chesse from dina , the medium is a classic bio soil / terraneous ( mix of Sphagnum, green compost , vegetable matters) that contain nitrogen 280g/m3 ; and phosphorus pentoxide (P2O5) 180g/m3 with a PH of 6.4, conductivity of 45 mS/m , i use HPS green power 400w , light schedule is 12/12 since four weeks now ,
temps are 86F during light and 64F during night , RH is low somewhere in the 40 to 50 % range , i give them bottled water with a basic PH of 7 , but i use PH down from general hydro to lower the PH at 6.5 and then add some nutes and feed them directly.

For the feeding schedule i use bio bloom(2.5mL/L) and a litte of bio grow ( 1mL/L ) every 4 days since the beginning of the flowering period, and between just bottled water with PH down .So basically i feed them every 4 days and watering them every 2 days.

add your nutes first, then ph. i use jacks citrus and it drops my ph 7.2 tap water down to 5.7 on its own

do they need watered every other day? seems a little excessive for whats basically soil

Roger , It gets really hot where i live so when temps outside are hot , indoor temps tend to rise too, that's an issue i can't fix cause i don't have an AC , but i have a bad tendency with overwatering , maybe start to lower watering ? i'am at 5 week flowering now i don't want to risk more issue at this stage it can mess up the final yeld , and she seems ways underdeveloped compare to her sister that is right next to her.

I will try to buy a Ph tester pen , for the moment i only have a chemical tester with a green liquid, biobizz nutes with their brown colour can mess up the colour result test of Ph.

What is your final Ph with watering /feeding?

well, i grow in either coco or promix, so for coco, i ph to 6.1, for promix, its 6.3.
for soil i would stay between 6.3 and 6.8. you don't have to get it the same every time, but you should stay within that range, with slow swings. start at 6.3, next watering, 6.5, then 6.8., than back to 6.5. that helps prevent lockouts.

yooooo time out! stop giving out bad dope guys....he is lacking cal/mag, for a couple of reasons he is light on these micros, first he may have started his bloom nutes too early which is a good possibility, and secondly his "ROOTZONE" PH may be off, would do what fishfryguy said, flush it out, as you flush test some of the runoff water to get an idea of rootzone PH, if the rootzone PH is out of the comfort zone, then you may have locked out your cal/mag, but snce your in flower im laning towards the early bloom ferts, you shouldnt start your bloom ferts till at least 2 weeks of 12/12, but since i am not there and its not my plant i would do the flush thing to check the rootzone ph, if, and only if your really lacking in cal/mag, you can flush with a 25% label dose solution to get your defficiency correct, but all the issues i see on here are PH related, when in doubt flush it out, this gives you a clean slate to work with, good luck!

he's an admitted chronic overwaterer, and you're advising him to water more? he's growing in soil, not coco, it's not a ph issue, it's an overwatering issue.
if he quits overwatering the problem should pretty much correct itself.
so are you sure he should add more water to this situation?

Roger A. Shrubber said:

he's an admitted chronic overwaterer, and you're advising him to water more? he's growing in soil, not coco, it's not a ph issue, it's an overwatering issue.
if he quits overwatering the problem should pretty much correct itself.
so are you sure he should add more water to this situation?

Click to expand...

you know what, i will agree with you to a point, only cus i looked at that first picture a lil longer and that looks like classic house plant over watering, when theyn get so pale yellow and fall off, but he got bigger issues, he is entering flowering without knowing what his PH is...Alexander, stop overwatering, dont give your plant water on regular shedules, let the plant dictate when it needs water, lift the pot if its really light it needs water, if it has a good weight to it then its fine, just dont let the plant go so long without water to where its wilthing and drooping.....roger , your still giving bad dope bro, dont just say "its not a PH issue"

@morrisgreenberg you right , i started bloom nutes too early , and drastically reduced the amount of biogrow , what I should not have done specially during the stretch.
To be honest i started giving bloom nutes the first week of switching.

Today i see more and more brown spots , more curly leaves , do i have to cut the infected leaves ? i've read that if i don't do this it can spread more, is it true ?

they aren't "infected", they're lacking nutrition, and you're drowning them from the inside out.

and morris, it's not a ph issue, the plant shows NO signs of ph problems. it shows OVER WATERING issues....
ph problems bad enough to cause this would also be leaving large bleached looking patches on leaves...i see no ph damage