Yellow Tips on Newer Leaves and general Yellowing of older leaves. (Day 50)

[Mugen]

Hey Forum

I'm a rookie grower and got no idea what's happening here, how severe it is, or what to do to help these ladies a little. Any input is much appreciated.

As far as equipment goes I have one MarsHydro 96 LED (goo.gl/U1QERB) about 25cm(~10") away from tops, plants have stopped vegetative growth 2/3 weeks ago. Got an exhaust vent and circulation fan in mother tent too.

I use BioCanna Bio Terra Plus (goo.gl/ejXgwT) with the corresponding set of nutrients and feeding schedule like recommended on their website, but just a little tuned down. Sadly no perlite in the soil this time. The pots are 11l(~3gal). Water comes from the tap and is a pretty high in pH, but as far as I heard that doesn't matter much with organic soil&nutrients. I water 2l(1/2 gal) whenever I feel it's needed. Which is about every 2/3 days.

I'm growing indoor in a 80x80cm(2.6x2.6ft), temps with lights on are usually 23-25C(73-77F) lights off 17-20C(62-68F). Humidity now at day 50 sits at 37-40% with lights and 32-35% without. I had some small black flies (potentially fungus gnats) in the first 4/5 weeks, but they died off at the rate of the plants growing.

I'm growing 2 AutoColorado Cookies from Dutch Passion, like I said they are 50 days in and they're definitely flowering and stopped vegetating. One of them is significantly slower (A) and more bushy, whereas the other one had a beautiful growth and proportions (B).

The yellow tips on top leaves are only on the weaker pheno, while both recently developed some general yellowing on the lower leaves. First pictures will be of A, the rest of B. I took pictures of sick and healthy leaves on each one, plus one of the yellow tips.

I only can assume it's nitrogen or zinc deficiency. General problems I'm aware of is a semi-heavy feeding schedule by personal choice, not enough airflow through plastic pots without perlite and maybe distance from the lights.


Again, thanks in advance to everyone taking the time to read this and possibly advice me.

 

[Waira]

looks nutritional related Mugen,.. that Mars LED, is it the 96x3 Reflector, or a newer 5w unit? You might want to raise it up another 6",...
The one lower leaf, 3rd pic, is N defc. symptoms, some of which is expected at this stage, though that one look heavily tapped already; the rest are harder to say... I need whole plant pics, in normal light for better diagnosis; oddly I see burned tips on that one top, but little to none elsewhere,... pale leaves and some other more subtle symptoms hint at P defc, starting, not unusual with such mild nute's, and what looks to me to be weak PK input,... Also, I see no mention of pH monitoring; organic or not, it needs to be watched, and your inputs tested and adjusted, or you're gambling blindly! Your water source is a potential issue as well, depending on just how hard it is (mineral content), and the pH,... the concern is if you're having a simple lack-of defc. problem, or if the pH is off enough to cause some nute elements to lock out (rendered unabsorbable due to chemistry changes),... do you have a pH meter, and a good quality soil pH probe?

 

[Mugen]

looks nutritional related Mugen,.. that Mars LED, is it the 96x3 Reflector, or a newer 5w unit? You might want to raise it up another 6",...
The one lower leaf, 3rd pic, is N defc. symptoms, some of which is expected at this stage, though that one look heavily tapped already; the rest are harder to say... I need whole plant pics, in normal light for better diagnosis; oddly I see burned tips on that one top, but little to none elsewhere,... pale leaves and some other more subtle symptoms hint at P defc, starting, not unusual with such mild nute's, and what looks to me to be weak PK input,... Also, I see mention of pH monitoring; organic or not, it needs to be watched, and your inputs tested and adjusted, or you're gambling blindly! Your water source is a potential issue as well, depending on just how hard it is (mineral content), and the pH,... the concern is if you're having a simple lack-of defc. problem, or if the pH is off enough to cause some nute elements to lock out (rendered unabsorbable due to chemistry changes),... do you have a pH meter, and a good quality soil pH probe?

Ahoy! Thanks for the reply Waira

Yes, that's the light I'm using and it's the new 5w. I'll try to raise it a little, although I'm afraid that the light will then not penetrate to the lower buds.

Ph is a little over 8 from the tap, which is far too high I know. For today's watering I used vinegar to ph it down to ~6.

Took some more pica in natural light before the watering. First 3 are from the weaker one, which seems to be get a little worse and the other 3 are from the stronger one.

 

[Mugen]

I trimmed the leaves that were clearly dead, I heard trimming, pruning and all of that is not very advisable with autoflowers so I hope that wasn't a mistake.

 

[Waira]

... the hammered leaves will fall off by themselves soon enough, when tapped out,... new pics help! First 3 show's some N defc., more than should be at this stage but not badly so, and some mild P defc. symptoms,.. second is more strongly P defc. showing that burnishing on the leaves,... I forgot to add, the reason oyu need to get that in-pot pH is to determine is it's lack of, or lockout issue,.. in the latter, adding more nute's will worsen things! Only alternative to a soil pH probe is the run-off method, usually dubious for accuracy! here's a link to an improved method and calculation for pH estimation-- ( https://www.autoflower.org/threads/...-for-run-off-testing-and-ph-estimation.41733/ )... so until that pH is determined, I can't say what the next step is-- simply adding more nutes, or dealing with the off-pH first,... if you want to gamble, add more nutes, just pH the solution first,...

 

[Mugen]

... the hammered leaves will fall off by themselves soon enough, when tapped out,... new pics help! First 3 show's some N defc., more than should be at this stage but not badly so, and some mild P defc. symptoms,.. second is more strongly P defc. showing that burnishing on the leaves,... I forgot to add, the reason oyu need to get that in-pot pH is to determine is it's lack of, or lockout issue,.. in the latter, adding more nute's will worsen things! Only alternative to a soil pH probe is the run-off method, usually dubious for accuracy! here's a link to an improved method and calculation for pH estimation-- ( https://www.autoflower.org/threads/...-for-run-off-testing-and-ph-estimation.41733/ )... so until that pH is determined, I can't say what the next step is-- simply adding more nutes, or dealing with the off-pH first,... if you want to gamble, add more nutes, just pH the solution first,...

Thanks a lot, got a ton of valuable information in that. I don't have a way of testing in-pot pH yet, but I will get one of those probes soon hopefully. Although it has gotten worse the past few days and growth has pretty much stopped, I think I have to gamble a bit right now. What I'm also noticing is that the soil is almost impossible to dig in, because of root growth I think, so in general my roots are kind of suffocating right now and water is barely penetrating everything it seems.

I'll have to improve all of this greatly next time around, which shouldn't be a problem. This is my first real grow and was supposed to be a learning experience.

 

[Waira]

...yeah, sounds like the root mass is pretty dense... look into getting a wetting agent too, something like Coco-Wet, or Earth juice Assist,.. this stuff takes the surface tension out of the water/nute solution, so it penetrates faster and more evenly,... I'd have you do a flush (run 2-3x pot volume of pH'ed water though the pot), but if penetration is that slow, it'll be an extra pain in the ass, possibly damaging to roots (smothering too long, over 20 min. or so root start to suffocate),... well, a gamble it is! Go ahead and give her bloom nutes and we'll see how she reacts,... next water only cycle, get enough in there to get some run-off, collected in a clean saucer or something,.. then pH test that; it won't be accurate, but it'll at least give a ball-park idea about in-pot pH,...

 

[Mugen]

...yeah, sounds like the root mass is pretty dense... look into getting a wetting agent too, something like Coco-Wet, or Earth juice Assist,.. this stuff takes the surface tension out of the water/nute solution, so it penetrates faster and more evenly,... I'd have you do a flush (run 2-3x pot volume of pH'ed water though the pot), but if penetration is that slow, it'll be an extra pain in the ass, possibly damaging to roots (smothering too long, over 20 min. or so root start to suffocate),... well, a gamble it is! Go ahead and give her bloom nutes and we'll see how she reacts,... next water only cycle, get enough in there to get some run-off, collected in a clean saucer or something,.. then pH test that; it won't be accurate, but it'll at least give a ball-park idea about in-pot pH,...

Soo, this might sound off to you, but I took one of them down today. There are several reasons why I decided to havest, first off my title is wrong it was probably at least day 60. Also, growth had stopped for about a week and around 98% of the pistils were brown at this point. Lastly, I have a loupe so I was able to check the trichomes and everything I could find looked pretty cloudy. The day of my last post was my last watering with simple water at around 6.3 pH, the pot felt dry and was very light today. The stronger plant is the one I took down, the weaker one still has a few days to go.

Got couple more questions if you don't mind first off, you are right the root structure was dense af in my 11l / 3gal pot, there were roots in every cubic inch. Like I said, next time I will add perlite, but do you think I should also get a bigger pot size? Also, do you have any idea why CANNA, the fertilizer company I use, claims on their website "The diluted nutrient solution does not need to be acidified" i.e. pH-controlled ? (http://www.canna-uk.com/bio-flores)
I think that's where I got it from and I think I also read this post http://www.growweedeasy.com/adjust-ph-organic-marijuana, but the information in there seems kind half-baked too.