P & K Def?

[Bekay]

Details of grow at:
https://www.autoflower.org/threads/deep-blue-c-in-promix-bx.50600/#post-987171
Any suggestions on keeping these girls going?

 

[briman]

Check the ph of your medium first. feed at your normal ph, get enough runoff for 1/4 cup of runoff and test it with a meter. Looks to me like ph is off.

 

[Bekay]

Briman, thanks for the response, the soil pH is and always has been 6.8 to 6.9 when measured directly with the soil-pH-meter. BTW 6.8 was what I measured when planting the seeds in the Promix BX. It has been measured daily and has never varied. I have not tried either measuring the run off or collecting run off after a distilled water flush since I have the dedicated instrument.

 

[Waira]

BK, what's up? .... Your pH probe, is it an Accurate 8 or equivalent? Not one of those skinny probe types we see at garden centers,is it? Those are notoriously inaccurate,...For peat based Promix, that's a higher than usual pH, part of the reason I'm asking about the probe too,... Plant in first pic looks like Ca defc., a less typical symptom form,...second looks more like the usual (need a close-up of that to be sure), but the yellowing going on with mid-upper leaves is something else, too generic to say for sure yet,... If your pH is that high, partial Fe lock-out is a possibility,...so is early S defc. (they look very similar, soil pH is a critical clue),...might be some P defc. kicking in as well, which makes sense at this stage,... you using any Ca-Mg?
...as for the run-off testing for pH, @briman -- collecting that type of r-o won't accurately reflect the soil pH brudda,... the idea is to get no other sources of pH influencing inputs messing with the r-o, and feeds, Ca-Mg, even tap water will do that... this guide wisely calls for RO/Di water on final pour through to make sure what comes out is not being altered by any buffering minerals reg. water usually has, after things have "steeped" in there with the usual watering method... https://www.autoflower.org/threads/...-testing-and-ph-estimation.41733/#post-928975

 

[Bekay]

Hi Waira,
Yes, it's an Accurate 8 as you recommended in my last grow (Stonington Blend). Aside from the constant soil pH of 6.8, all the rest of the factors seem okay on paper, but clearly something is wrong. When the pH was noted as stable but high, Waximus recommended dropping the pH of the feedings to 5.5-5.7 from 5.9-6.0 and it has been kept there ever since. The only thing that is different for this grow has been adopting a 2x/day low concentration feeding without run off. The ppms have been between 258 and 502.
I have copied the grow log update here for your convenience:

Day 38 Update
It has been a hard couple weeks for the girls. Seems to be issues with P and K if I am reading the pictures in the Deficiencies post correctly.
Vertical growth has stopped with tallest plants about 12 inches. The feedings have been 16 oz twice daily of these concentrations in a gallon of filtered tap water:

Buddha Grow (2-0.25-1.5) 15.0 ml
Voodoo Juice 5.0 ml
Roots Organic Trinity (0.1-0.5-0.25) 3.2 ml
Carboload 3.8 ml
Earth Juice MicroBlast 2.5 ml
Cal Mag (2-0-0) 2.0 ml
total ppm's between 258-502. [charcoal filtered town water is 128 ppm, 6.4 pH, no chlorine smell or taste]​

I am surprised to see what looks like deficiencies but maybe it's pH lockout. I got an Accurate 8 soil pH meter upon recommendation by @Waira and have been routinely feeding at pH 5.5-5.7 yet my soil reading has never changed from 6.8-6.9. Can't figure out why that is. Pots have never generated anything but miniscule runoff and have not been flushed or only watered. They have been on feeding continually.
Two days ago I watered with 1 tsp Epsom Salts per gal. twice and skipped the feeding. No apparent effect.
Yesterday I started the flowering phase nutrient schedule and swapped the light to HPS from MH.
Temps and humidity are at 67-83F and 30-45%. Light is 18 inches above tallest plant.
Bloom phase feeding schedule adds Buddha Bloom(0.5-2-1), Big Swell (2-5-3) and HP2 (0-4-0) in modest amounts and reduced amounts of Buddha Grow and Voodoo Juice. 485 ppm total after adj. pH with Botanicare UP (0-0-16; potassium hydroxide)​

I have a couple close ups of the leaves for your inspection too.

With CalMag added (Technaflora's MagiCal brand includes Fe) and MicroBlast in every feeding I thought I would have taken care of those needs. I needed some more pH Up for this grow and found that Botanicare was recommended by someone on the forums so I bought a bottle. I see this is heavy in K. Is that unusual? Could these be signs of toxicity instead of deficiencies? As I went to the tent to take thes pic's I see that I have some clawing on the new growth at the cola. Perhaps I have reached an excessive amount of nutes or maybe the Epsom Salts treatment pushed them over the edge? I don't know. Should I flush them?
Thanks for taking an interest Brother.
Peace.

 

[briman]

Thanks @Waira for redirect! learn something new today!

 

[Waira]

Cheers Brim'! ..you know how little I like run-off testing as is,...this method does at least address some of the glaring common measurement errors that it's prone to! :smoking:

>> Bk-- good pics mate! -it helps a lot, as does the nute data! I think it'll clarify the issue some... looking at that NPK info, I see very little P-- too little in fact even combined, it's still less than 1.0,...here's a more atypical P defc. pic-->

.... P is needed for many things, all the time, even in veg', just like some N is still needed during bloom,.. they just don't get top billing respectively during those stages,... (N is low too, and you might have early fan consumption during bloom, because the plant didn't stash enough away earlier),... you're feeding lightly too, so that compounds things... I think if you were in hydro, things may not be as bad because of the constant low level availability, but in soil, matters are far different...*wait*-- you say you're feeding 2x/day, no run-off? That's fine for soilless, like coco, or peat mixes, but true soil, it's not,...water/feed thoroughly, with some run-off especially with water alone, alternating feed and watering; going organic means some delay in things getting in there, since it's the microbes that are breaking down things into absorbable forms; using inoculants and EWC teas (worm poop) will help keep those population up and balanced,... So, with bloom nutes and supplements started, the extra P is going in now to treat P defc.,... I don't go by ppm's, so how far off of full strength are you feeding? As mentioned above, feed less often, but at higher conc.'s,...
>> I don't think Fe is really in play here, or if so, very mild..nothing distinct so far,... That said, Fe and S seem to be covered by the Microblast (and epsoms, for S), BUT keep in mind, Fe locks out fast at around 7.0, so even if it's there, it becomes unabsorbable,...(S is fine at that pH, so no worries there).... leading to the question of your soils stubborn pH...with your feeds that acidic, it should have brought down the soil pH some by now,... must be lots of lime in there -that would explain things some! Ideal soil pH is mid-to-low 6's,... Well, for now, keep pH'ing your feed in high 5's,...

 

[Bekay]

Thank you Waira! Your picture looks just like my plants so I think you have isolated the problem(s) to a P def. I am growing in Promix BX, unammended - straight from the bag. Here's what the mfr.'s site says:

PRO-MIX® BX MYCORRHIZAE™
BX - general purpose

PRO-MIX® BX offers a solution for growers seeking the benefits of added vermiculite for improved nutrients availability and a perlite content providing limited but proper drainage capacities. Combine with high quality fibrous peat moss, this formulation is ideal for growers looking for a general purpose medium which creates a well balance growing environment.

• SPHAGNUM PEAT MOSS (75-85%)
• PERLITE
• VERMICULITE
• LIMESTONE
• WETTING AGENT
• MYCORRHIZAE™ PREMIER TECH

As for nutrient concentrations I am at 50%; here are the "per the bottle recommended amounts followed by what I am (currently) using:

Buddha Grow (2-0.25-1.5) 15 ml/gal, using 7.5 ml/gal -will reduce to 3.8 in ten more days
Buddha Bloom (0.5-2-1) 15 ml/gal, using 3.8 ml/gal -will up it to 7.5 next feeding
Trinity (0.1-0.5-0.25) 5 ml/gal, using 2.5 ml/gal
Big Swell (2-5-3) 5 ml/gal, using 2.5 ml/gal
HP2 (0-4-0) 5 ml/gal, using 2.5 ml/gal
MicroBlast 2.5 ml/gal, using 2.5 ml/gal
CalMag 2.7 ml/gal, using 2.0 ml/gal
Voodoo Juice 7.5 ml/gal, using 3.8 ml/gal -will stop with next feeding
Carboload 7.5 ml/gal, using 3.8 ml/gal
Overdrive -not used yet, planned for Days 50+
​

The low dose 2x/day approach was a hand-watering imitation of TaNg's approach and like Waxi's DTW system. I can abandon that approach and return to alternating water/feed/water/feed till runoff, which in fabric pots (last time) took 5 or 6 days to dry out between watering/feeding events. That meant they only got fed every 10 or 12 days. I have about 30-40 days left in the grow and that means they will only get fed three times more. I was hopefully going to be giving them more nutes in a useful ongoing fashion by my plan. Go back to the old way...is that what I hear you telling me? Should I up the HP2 to 100% or more to get some P in there quickly?

Thanks Waira.

 

[Bekay]

Go back to the old way...is that what I hear you telling me? Should I up the HP2 to 100% or more to get some P in there quickly?

@Waira Couple of hanging questions. Any thoughts?

 

[Waira]

Promix is good stuff, so no worries there,.. but it's not coco, which is a whole different ball game vs soil, and that's what Waxi' is using; TaNg, I'm not sure what he uses, something peat based I think,...but he's not doing organic like you, and that changes things as well,.. recall what I mentioned above about breakdown times and such,... synthetics are typically right-now available, unlike organic nute's-- it's a little more tricky going this route, and I don't think adopting this little feeds, all the time method is good for organics,... Hmm, that's a rather long dry-out time for fabric pots, I see the dilemma,...do you have decent air movement in there? T and RH are fine,... Do you buff the A8 tip clean with the pad it comes with before each reading, and let it sit in there for a few minutes? Soil should be well moistened too-- both important to get good readings,... just out of curiosity, test the soil in the bag too and see what it reads,... do you have HPK? The HP+BS give a 2-9-3, Grow/Bloom adds little more K....Yes, to upping the P inputs, but K is just as important, and given the mildness of the base nutes, and HP's lack of K, keeping that in step with the P is wise,...