Dinafem Cheese XXL Auto - New Growth Yellow (and burnt tips)

[Life_On_Mars]

Problem: New growth coming in pale/yellow, also burnt tips (probably two separate issues but worth mentioning)

Medium/grow method: Soil, organic(ish).

Feed: and supplements used: 2x Biotabs in potting soil, orgatrex, bactrex, + bio P.K 5-8 in the last couple of weeks. Only started feeding around week 3-4 when they started showing some deficiencies. Also some vitalink calmag with most waterings since around week 2/3 since they were showing some possible calcium/magnesium deficiencies.

water source: Tap water. Chlorine/chloramine is neutralised with ecothrive neutralise (it's hard water, around 300ppm) and some PH Down to bring the water into the 6.5-7 range.

Strain/age: Dinafem cheese auto xxl, just starting week 8.

light used: Mars Hydro TS 3000, pulls 480w.

Climate: It has gotten warmer in the grow tent in an effort to control the humidity, so day temps have been around 26-29 and night temps a couple of degrees lower. It can swing lower in the day though, and higher at night, I wonder if this mismatch could be causing this issue? Relative humidity sits around 45-55% (usually at the lower end now).

Additional info: They're on a 19-5 light pattern. They're in a 'swick' system, in 3 gal fabric pots, sat on top of 5 gal fabric pots that have 4 inches of perlite. This bottom pot then sits in a reservoir tray that I fill with PH'd water (sometimes with a bit of calmag) and it 'wicks' up the water it needs. The bottom of the soil never sits directly in the water, the perlite is in between. This system seems to have been working very well, and overall I'm super happy with the growth of these plants, it's just this one that's yellowing out.

At first I thought it was a nutrient deficiency so I gave them a feed with some organic bloom feed (biotabs bio PK 5-8) but they actually got a bit of nute burn as you can see. And whilst they're still all growing great, this one plant is still yellowing and it's getting worse. Doesn't seem like N def, because it's mainly in the new growth. I've checked the soil PH and it's showing just under 7, which is a bit high I know, but shouldn't be causing lock out? Especially not in an organic grow?

I wonder if the slightly high/inconsistent (occasional spikes during lights off) temps have caused this issue, this one plant is right in the corner where temps might potentially be worse... I'm also concerned about the grow tent giving off gases. Is there any way I can test for this? I can't really take the plant out of the tent for a night, they stink too much and I don't have a second light. I'm also wondering about an iron/sulpher deficiency, but again I'm not sure.

There are two phenos from this grow it seems, one short and stocky with lots of bud sites, and one tall, one of the stocky ones is affected (the most beautiful, resinous one, surprise surprise!). The 3 that are the tall pheno seems unaffected, but I'm starting to see some signs of yellowing on the other stocky pheno one, so I'm worried it's going to start showing the same signs soon.

It looks worse in real life than in the pics I'd say. It's still growing fine, but new growth is VERY pale.

 

[Life_On_Mars]

Just took this to try and really show the lightness of these leaves - once I took the pic I noticed the browning on the leaf edges, and also noticed the the very top sugar leaves are not actually super pale, it's the buds newer supporting fan leaves that are really yellowing.

The burning along the leaf edges is making me think it's actually EXCESS calcium, causing the nute burn look, but also locking out stuff like magnesium or potassium?

My tap water is very hard, and I've been adding calmag (I did this after hearing that all LED grows will need supplementing with calmag, especially with long light periods like you have with autos, now I'm not so sure...). Maybe they're hungry for other nutes, but overdosed on calcium?

Here is a top down pic of a different plant from this grow (same strain but different pheno I think) that is NOT showing yellowing, for comparison -

 

[Life_On_Mars]

Gave them some epsom for a mag/sulfur boost a couple of days ago, as well as a feed, she's still growing but also still fading. If the epsom salts are the answer, then how long could I expect it to take for them to 'kick in'?

This is all one plant, and it's the main one showing issues. I know it's not like it's doing terribly, but I can see it lightening up day by day, and it's the frostiest of the five packed into my 4x4 tent, so it'd be a shame for it not to reach it's potential!

Lower leaf - Mag def right? And possibly a bit of cal def too? Bear in mind this definitely started at the top, at the new growth. The tops just started really lightening up, looking more like a sulfur def than a mag def.

Checked the soil PH when I first saw the issue - it was just under 7, which I know is technically OK but also a bit high (and could be potentially be locking out magnesium if I understand correctly) so I lowered my water PH from 6.5 to just over 6 and filled the water tray with that. The soil is now sitting at just over 6, so I slightly overcorrected I guess! I'm assuming now that I give I'm giving it straight forward 6.5 water again it should even it back out.

Since I did the second orgatrex/bactrex feed (as per the biotabs instructions) I've been feeding with Bio PK5 5-8 and a splash of orgatrex, once a week. However, I think it's important to note that I've whilst I've been mixing them as recommended, I haven't been giving a full water feed, I've just been giving the plants a litre of the ferts each (slightly distributing extra to the ones that looked hungrier). However, they're probably drinking about 3-4 litres of clean/calmag'd water a day, so the feed I'm giving them is a good 2/3 times less than recommended. I've always heard 'half strength for autos' and I already had the burnt tips, so I didn't want to overfeed them. Plus the plants are sat in the water trays and bottom feeding, so I can't add the gloopy organic liquid nutes to the tray as it will just gunk up.

Is it possible that this could be -

a) They just need a proper feed? The lime/yellow colour did come through towards the end of the stretch, when the plant was growing extraordinarily fast.

b) It's actually just fading out and heading towards the home stretch? It seems unlikely at day 53, but this one plant did seem ahead of the others, it sprouted faster, hit flowering faster, and frosted up before the others...

According to most other grow diaries I've got about 3 weeks left on these ladies, as it even worth faffing around with flushing etc trying to fix things now? Or just up the feed a bit and hope for the best?

Thanks!

 

[Waira]

-- EBC, let's have a look here,...
Some big picture stuff:
-forget about tent gases, not an issue
- T and RH% look fine
- top yellowing out smacks of a micronute defc., most of these are immobile within the plant, meaning they can't be translocated to new growth from older tissue
- question is, the defc.'s caused by plain lack-of, pH, and or lockout due to that or an antagonistic (competitive) uptake problem... *(have a look at the Defc. Pic Depot in the sticky section above this one; page 2 lower area shows various charts, graphs illustrating this)

First thing that concerns me is that hard water; at 300+ppm, it's bloody loaded with CaCO3 and cumulatively, it can start to both drive pH up and start to load the soil with mineral crap that screws with the uptake of other nutes,... The soil can buffer it some, but only up to a point; often soils do better buffering acidity (with lime, etc.)...... I'd switch immediately to a new water source, pain in the ass as it is,... self fill machines, bulk drinking water, anything you can get that's low ppm,...
How exactly are you getting that in-pot pH reading? If it's not a good quality soil pH probe (wrongly called a meter sometimes, meters techinically are for solutions only), then the reading may be dubious for accuracy,.. That said, the reading you have fits with the hard water issue; most micronutes like Fe, Zn, Cu, Mn, B start to lock out near 7.0, give or take a couple points here,.. lots of mitigating factors in maintaining availability in soil, pretty dynamic actually,...
Probably compounding this is the ion load in that soil, made worse by the addition of Ca-Mg; it's definitely more available than the water borne hardness CaCO3, but what happens is a vicious circle of sorts,.. Ca and Mg can both start to block each other out in antagonistic uptake, as well as screwing with the micro's... coupled with off-pH, and things start to really snag up! Nutrient imbalances can start to snowball, bottlenecking uptake of others even if present.... B, Si and Ca are key players early on in this nute uptake process; lack or too much of them can make troubles downstream....
....other possibilities: P and S... That lower pic of the leaf shows multiple signs, but P defc. is among them (patchy necrosis); I find that localized yellowing often happens as well, and while P may be mobile, it seems to be drawn from closer sources, unlike N defc. which is most often seen on lowest level leaves...
Too much Ca locks it out too,... Mg defc. doesn't yellow out the veins like that....
S is immobile, hits tops first and worst, and broad scale yellowing top to bottom is common,... that locks out under high acidity though. I can't seem to find much info about it for antagonistic uptake though - ... SO4- - is the ionic form plant want... it's pretty reactive, and may compound with Ca, forming gypsum basically! .... what your inputs there are is only a guess from the Biotabs and PK (if any), epsoms of course are a good source...

So what to do,....the Biotabs deal means flushing is a very last resort since it'll leach nutes out, worse, CaCO3 is poorly soluble in water alone, pH depending... the Tabs may be close to depletion too, so there's that to consider,... PK booster is not a balanced nute product, not meant to be... a base bloom nutrient will be, which Biotbas doesn't have of course...
How to reduce the load in there is the catch -22 as you see here,... Since it's worsening, and you have only a couple-few weeks left, you may have just gut out the flushing with low ppm water, helping to reduce the CaCO3 load in there a bit and correct the pH, which BTW will fight back pretty hard toward neutral pH,... the CaCO3 will dissolve releasing the Ca and carbonate, latter is what does the pH buffering,... Free Ca++ may helpful or hurtful if too much is in there, and remember, we are just speculating about ALL of this, with no empirical measurements to quantify a damn thing...
If you flush, 1-2x pot volume, you will have to feed something balanced, that has secondary and micronutes, not just NKP....
In the future, especially with organics, look into a Si and humic-fulvic product,... (good info in the Reference section about them)
OR you just switch to that softer water, feed best you can, adjust the pH down to 6.0, maybe even a round or two at 5.5 to help drive that pH up some,... Caveat: pH adjusters are additional ppm's going in, more ion load.... .... diagnostics are a bitch!

 

[Life_On_Mars]

Thank you Waira! I really appreciate the assistance.

I think the tabs did burn out, maybe even a week or two ago, as I got that signature tip burn that you and EOF were referring to in your grow threads. Around week 4 (I think) I gave them the standard 500ml orgatrex/bactrex feed that biotabs recommend, and it was about a week or so after that that I started seeing these deficiencies, at a time when they were growing crazy fast - which is why I wonder if they're just hungry. So I can safely assume it's not definitely not an NPK issue if the deficiency starts at the top of the plant? I should say, there has been SOME yellowing and issues on the lower leaves, but I just assumed that was just normal drop off as it progressed through flowering and let those leaves die?

I'm not using PK Booster, I'm using Bio PK 5-8, it's 2-5-8 and the website says this -
BIO PK 5-8 contains BioTabs’ flower boosting formula combined with trace elements, phosphorus, potassium, calcium (2,5%), molasses, humic acid and vitamins A, B1, B2, B3, B12 to ensure your plants flower to their maximum potential.

I was leaning more towards this more than the orgatrex because I didn't want to do overdo the nitrogen, a couple of other plants (the ones that aren't showing issues) look like they've maybe got a touch too much N - leaves on the darker side with a couple of buds that have crazy amounts of leaves -

Could I not blend the PK 5-8 with the orgatrex/bactrex? to get a more balanced(ish) bloom feed? My understanding is Orgatrex DOES have available micro nutes etc?

Side note - why do fertilisers aimed at cannabis growers have the most ridiculous names? Orgatrex... it sounds like a sex robot.

Soil PH is being tested with an analog soil tester that looks like this -

I agree on the hard water. It's a bitch. I'm trying to avoid installing an RO system as it is a pain a creates a lot of waste water. I've ordered some RAW amino acids, which apparently can help to transform the CaCO3 in hard water into a usable form of calcium for the plants. How effective that will actually be, I don't know. Didn't even know about the whole ION issue! I'm adding PH DOWN every time, so that's not going to help with that.

I do have ONE reliable source of basically zero PPM water - from my aircon (that I'm using as a dehumidifier). What do you think about mixing this with my tap water? I can bring the PPM down easily. All the professional advice I can find says it's 100% fine for plants, as it's extracted through condensation, so its 'pure'. but I've seen lots of scary talk in these type of forums about 'heavy metals' in the water from aircons/dehumidifiers, I have no idea if it's actually accurate - any thoughts on this? The PPM of the water from it is around 30, so very low.

Bear in mind as well that I have this whole mass of roots BELOW the main 3gal smart pot, in the second 5gal pot with the perlite in it, and I can see the roots poking out the bottom and sides of the 5gal pot. I wouldn't be surprised if those roots are completely clogged up with a hard layer of calcium that is affecting uptake. There's also a bit of algae growing up the sides of those bottom pots, which I hadn't been concerned about before as everything seemed healthy, but now I wonder if that could be affecting things too.

That pic is a couple of weeks old and you can see those white dots are the roots - NOW the roots have snaked their way all the way through the 4-5 inches of perlite and out the bottom of the second pot. I don't know if I should trim them, or if I should be aiming to keep them wet (as that's what I've doing up until recently and it seemed to be working well - am I doing some kind of weird organic hydro?)

I wonder if I should pull the top pot out of the perlite pot so I can see the root mass underneath, and either clean those roots or even trim them off? I'm concerned about damaging the root system of what was (up until a week or two ago) a very healthy and fast growing plant! The top pot with soil in it is rock hard with roots as you can imagine.

I cut the calmag for a few waterings after I saw the burnt tips, and that was around the time this started, so I've put the calmag back in.

I just checked the soil PH again and it doesn't seemed to have climbed much since yesterday, still looks around 6.2ish. The fact that it's not rushing back up, I'm assuming is a good sign that maybe I'm not clogged up with salts from the hard water?

This might be a bad idea - but I'm still thinking I'll give them a proper feed tonight just to be SURE they're not just hungry (there are other grow diaries of this strain with people saying they do get really hungry in flowering, and I think the stingy litre of feed a week might just not be enough considering they drink a good 3-4 litres a day) and if that doesn't improve things in the next few days then I'll flush I guess.

Thanks again, and sorry for all the questions!

 

[Life_On_Mars]

So... I noticed that the yellowing was all in the spots where the light was strongest, the colas round the edge are less affected (even tall ones with plenty of new growth), so I downloaded a LUX meter to my phone and had a scan around - the areas with the most yellowing were getting a around 110K lux, which I understand can be more than enough to cause light stress on some strains. My 480w LED was at around a 12-14 inches. I've raised it to 18 inches, so they're getting about 70-80K now, which is in the safe range as I understand it.


I've been looking up light damage, these are not pics of my plants, just examples of similar light damage -

The fading on that last one looks very similar to mine in the way it progresses downwards and is concentrated in certain spots (minus the droopiness, thank goodness).

I know this doesn't explain the damage on that lower leaf, but I did have to hunt around to find that - most of the lower leaves are green and healthy except some of the ones that are fully hidden by overcrowded canopy above, and those just seem to be slowly yellowing out naturally. It would make sense that it happened just after the stretch too, as I had the light at around 24", and let the plants 'grow into' the light.

The only thing that doesn't make sense is that there are three other plants (same strain) that are much taller, and aren't showing signs of damage (although they are 'praying' pretty hard, which I can be symptom of too much light) - however those three are clearly a completely different pheno than the two that are showing symptoms, so I'm assuming there's a chance they could just be less light sensitive?

Could it be that this has all just been light stress?!

 

[Life_On_Mars]

In case anyone comes across this thread with similar issues looking for help - Update to this here -

https://www.autoflower.org/threads/dinafem-cheese-auto-xxl-day-43-frosty.78865/page-2#post-2310886

TLDR - my soil probe PH tester is utterly inaccurate. I will be sticking with a soil slurry test with distilled water and a calibrated PH pen from now on. When I did this it showed me that my PH was far too low - around 5. I've flushed them. My soil probe PH tester was telling me my soil was too alkaline.

 

[Sensi Jay]

Yes 100% light stress, had a very similar thing on the tabs grow in my sig. Some excellent info on here though. Worth a sticky mods?

 

[Life_On_Mars]

Yes 100% light stress, had a very similar thing on the tabs grow in my sig. Some excellent info on here though. Worth a sticky mods?

Thanks for confirming - I just skimmed through your grow to find a pic and see for myself - great plants! And yes - it definitely looks like the same issue. Were you using LED too?

 

[Waira]

- pardon the lag mate, I got buried,...

So I can safely assume it's not definitely not an NPK issue if the deficiency starts at the top of the plant? I should say, there has been SOME yellowing and issues on the lower leaves, but I just assumed that was just normal drop off as it progressed through flowering and let those leaves die?

Yup, as a general rule that's true,... My bad on not asking about light distance, that may have been a contributing factor but not the whole cause IMO,... That pic of the leaf shows P defc., not surprising because of the demand...
Micronutrients are mostly all immobile within the plant, Fe, Zn, Mn, B, Cu etc.,... Once established in tissues they can't be translocated to high demand growth anymore,... And in BioTabs I seem to see micronute defc. more often than usual. My choice for fixing that is earth Juice Microbalst, but overseas, it's not available. I like it because it's just micro's in rich conc., unlike kelp and most other products,...
I have no idea about how amino acids can affect solubility of CaCO3 (fairly poor solubility in water), in hard tap most of it isn't dissolved....
Same for AC water, I'm not exactly sure where that water has traveled in the system,... where it would pick up "heavy metals" is a mystery to me, and which ones? That it had 30ppm is something to consider, that's not insignificant, but what's dissolved in there is the question... Only ions will be measured by the TDS meter because they help conduct electricity...

I'm not using PK Booster, I'm using Bio PK 5-8, it's 2-5-8 and the website says this -
BIO PK 5-8 contains BioTabs’ flower boosting formula combined with trace elements, phosphorus, potassium, calcium (2,5%), molasses, humic acid and vitamins A, B1, B2, B3, B12 to ensure your plants flower to their maximum potential.

That's a PK booster! ..above and beyond what the tabs provide at least,... Blending is fine...
Roots aren't the issue here in terms of what you said,... but constant soggy base is a worry for root rot, so watch out for that... Algae unless is bad isn't an issue either, just a nuisance..
pH is fine, so the CaCO3 load is being dealt with on that level at least...
Keep on the feeds, don't flush unless it's a shit-show for pH and massive run-off ppm!