Yellowing/dying lower leaves and my analysis paralysis... Any advice?

Hey folks, I've got some lower leaves yellowing and as of today they've jumped as high as the third node. Initially I was thinking an N deficiency however the last time I gave them a feeding containing a modest amount of N (tiger bloom @ 2-8-4 3/4 dose) a few of them showed some clawing.

I'm in smart pots and they only get watered when the pots are dry at which point the plant is a bit droopy so I'm hoping that rules out overwatering.

This morning they received a full dose of cal-mag plus due to some spotting that a few members noticed on a separate thread. Not sure if this is the continued evolution of a cal or mag deficiency but at this point I'm a bit worried.

Here are pics of the symptoms on 2 separate strains in addition to a pic of all 5 plants taken today.

I would`nt worry about anything that far down the plant

You need to feed more potassium, give some N till the end of week 4/6 if its an 8 weeker your going for

2-8-4 that`s a lot of P you need more K

yeah some more N may save some leaves but you want to grow buds not leaves who cares your cutting them all off come harvest time

anything lower than half way down the plant don`t overly matter unless your side lighting hard or doing a vert grow

Remember most people forget that too much cal and phosphorus can cause a calcium phosphate build up that can cause nute lock up

Flush! With clean fresh properly ph water well. let them dry completely then fert them again with something higher in N and a little less P and I disagree that you should not worried but I will say you should not pannic. Just do that and hopefully you will fix the problem. I would strongly consider getting a ph and tds tester to make sure you are not locking out. That's what I would do but that's just an opinion also keep in mind that could just be from flowering bc some strains do and will yellow fan leaves while approaching harvest and maximum potency

Gotcha. Ok my immediate bloom nute alternative is advanced nutrient's mother earth bloom 3-2-5. I thought it was weird how the values different so much from tiger bloom's given they are both touted as bloom nutes. I opted for tiger bloom because I've been using FF grow big and big bloom but I'll switch to this bloom 3-2-5 going forward for the bump in K. Here is a link to exactly what I have if that helps.

cap master said:

Flush! With clean fresh properly ph water well. let them dry completely then fert them again with something higher in N and a little less P and I disagree that you should not worried but I will say you should not pannic. Just do that and hopefully you will fix the problem. I would strongly consider getting a ph and tds tester to make sure you are not locking out. That's what I would do but that's just an opinion

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I PH up/down with every feeding and started with FFOF right around 6.3. There was a point very early on that I wasn't testing my water but that was during the second week or so, since then I've ensured everything going in was between 6.3 and 6.6. It sounds like your recco on the nutes might also be covered with my switch to bloom 3-2-5 right?

At their current watering rate, they will be up for a watering Saturday morning-ish. Should I just flush and go with just the bloom 3-2-5 then?

Yes those notes sound like a way better rounded fert to be using and will boost the n and K. I would check your water coming out of them bc even tho you have water checked before it goes in you could have substances in your soul such as peat if personally had problems with where it will hold on to salts and such from the water and they can build up causing lock out. That's what I would be concerned with. Test flush and fert is all you can do but otherwise your plants are looking good and strong

Good deal, thanks a ton guys!

@cap master - So I just got done flushing them. Water going in was between 6.4 and 6.6, water coming out was 6.2 to 6.3. If the build up impacts run-off like that, should I be watering close to say 6.7 or 6.8 to help counter-act it?

On a side note, I also learned that these can take about 30% more water before any run-off occurs so while the pots have felt heavy when I'm done watering in the past, I don't think I've been giving them enough. I basically had to give them nearly double what I normally would before the first drop came from the bottom.

In any case, as you suggested I'll wait until they dry out before going with the better 3-2-5 nutes.

yeah when I water I usually keep mine near 7 give or take a few points. when you water if you have to water a gallon before it runs out then I would water it with 5-6 gallons whatever amount it takes to achieve heavy runoff times that by 5. after a heavy flush like that let them dry completely until that pot is no longer heavy that will help promote root growth as well as give them a clean pallet for the new ferts

how far into flower are ur plants . them leaves are just old , they not getting light and they probs getting wet when watering ur plants . u probs knocking soil ph all over if using ph up and down . ffof soil has line added to it ti help buffer soil to a ph that cannabis plants thrive on ,ive never ph'd my soil for over6yrs . u only need to ph really in hydro .

trippytrappy said:

how far into flower are ur plants . them leaves are just old , they not getting light and they probs getting wet when watering ur plants . u probs knocking soil ph all over if using ph up and down . ffof soil has line added to it ti help buffer soil to a ph that cannabis plants thrive on ,ive never ph'd my soil for over6yrs . u only need to ph really in hydro .

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My well water is extremely acidic and ranges from 4.2 to 4.6 (after a good rain). If I add something like tiger bloom to it, it drops down to high 3s. They are about 45 days old and the plant that I took the worst shots from is starting to frost (pic attached) so maybe age is playing a part here too. It is a candy kush with a 65 to 75 day timeframe listed by the seed bank.

dosnt matter , the soil ur using has buffers in it to buffer it bk up to 6.2 -6.5 , you don't need to ph ur water going in the pots , u don't even have measure run off , I just check run off once in a while ,
if your water is 4. odd and u manually take it to 6.2 by adding ph up and down then once u add that to ur soil over the course of couple weeks u send the buffers in the soil all to fuck , so my advice to u is get ur water add what ever ur adding to ur water , dont ph it , just give to ur soilonce it goes through the soil the buffers will take it bk to 6.odd

Just wanted to post an update on this. The issue seems to have slowed down a bit after the flush then CalMag treatment however some of the upper leaves are now showing the same signs. Trichs are primarily clear, some cloudy and a few ambers here and there. Here are a few shots from right now, sorry about the weird yellow lighting on the one shot, I think my phone flash kicked in or something.

Ok here is a far better shot of the most troubled plant (candy kush far right) in addition to a shot of them all. This poor plant is looking so f'n pissed at me right now. I wish I understood what it is trying to tell me but I'm at a loss. Any ideas?

Guys guys, I have another clue that I think may shed some light on the problem. Other than for the purposes of watering and quick inspections, I don't really enter the tent much. I typically use the observation windows which allows me to see temp & RH. What it doesn't allow me to see is the little high/low values on my thermometer. It has gotten cold at night these past few weeks. I wasn't worried about it because I run my lights through the night.

Last night I was in there looking closely at the leaves and noticed that the low inside the tent at 8" below the light was 67°!!! The high was 84°. I remember reading that temp swings should not be greater than 10° and further reading on the impact of low temps indicates that they alone can cause P lockout starting at 68° which then can impact Cal/Mag uptake. I've reconfigured the environment a bit and last night the low was 74° while the high was 81°.

The timing of the onset of the cold weather, this plant's rapid decline, and the visible symptoms of the plant itself seem to line up so what I plan to do is flush her again but this time with a good 5G or so of water. Once dried I'll apply 1/3 or 1/2 dose of the organic bloom tea and see how she does.

if you were in hydro, those first couple of pics would be classic root rot symptoms. i'd add a good dose of soil benes on top of what you're already doing, see if they can out-compete any pathogens that might be present, i like a mix of scd bio-ag(lactobacillus culture) and this stuff
https://www.amazon.com/gp/product/B01CS2T9Z4/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
it has a load of good stuff. you have to ph it to 3.4 for the lactobacillus, but your soil should buffer that np.
try it out, makes your roots explode, and the rest of the plant responds in kind

Roger A. Shrubber said:

if you were in hydro, those first couple of pics would be classic root rot symptoms. i'd add a good dose of soil benes on top of what you're already doing, see if they can out-compete any pathogens that might be present, i like a mix of scd bio-ag(lactobacillus culture) and this stuff
https://www.amazon.com/gp/product/B01CS2T9Z4/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
it has a load of good stuff. you have to ph it to 3.4 for the lactobacillus, but your soil should buffer that np.
try it out, makes your roots explode, and the rest of the plant responds in kind

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Thanks for the feedback man. Currently they are in pure FFOF. Looking through a mass of bookmarked soil recipes now for my next round, man this stuff is intimidating but I'm enjoying the learning process. Will pick up the above, looks like this stuff will be very useful in future grows.