P def -- why for?

[whythefnot]

LOL Smiling big Ynot!!!
Ratz
You be getting some style my mang!

Maybe not the kind I'd like ...

 

[whythefnot]

Here's something...
http://www.growweedeasy.com/ph-fluctuations-cannabis

The weird thing is the pH hadn't fluctuated for weeks, until I responded to this problem. Could this problem have laid dormant for that long before expressing?


Here's why I initially thought it was a P deficiency (haven't entirely ruled out P def by pH):

http://www.growweedeasy.com/phosphorus-deficiency-cannabis

 

[whythefnot]

So it still just generally looks like symptoms of low pH to me. Mind you, they're not typical symptoms of low pH at all. But when I put all the pieces of the puzzle together, it seems like the pH has been slightly low for a very long time, and now that they're trying to flower, they're having a very hard time uptaking the proper nutes. Makie el senso??


Not everything I'm seeing looks like P def, but some of it looks just like this (progression of P def):

 

[Ratzilla]

Y not if your convinced that it is a P deficiency and you think that there is plenty of P in the soil then figure that you must of harmed the fungi in some way. The mycorrhizae fungus is the main player in P up take.
Inoculate with mycorrhizae by putting some in your water right before watering your plants.
If your wrong no harm done.
Ratz

 

[whythefnot]

Y not if your convinced that it is a P deficiency and you think that there is plenty of P in the soil then figure that you must of harmed the fungi in some way. The mycorrhizae fungus is the main player in P up take.
Inoculate with mycorrhizae by putting some in your water right before watering your plants.
If your wrong no harm done.
Ratz

Thanks, I already re-inoculated with mycos, but bear in mind that the last compost tea I gave them (a few weeks ago) was a fungal brew that went for 4 -5 days at ~ 60 deg F, and that my soil has a high percentage of light warrior, which come pre-inoculated. I haven't done anything at all to my plants in the last week while this has been going on, other than dialing in the blumats, so I can't imagine what I would have done to harm the fungi. There was one day that the temps got to 83 for a few hours, and I dropped the lights about 2 inches (from ~12 to ~10) the day before this happened...but that's seriously all that's happened. They've have a perfect environment.

These symptoms have coincided with the drying of the pots. That's the only common factor I've been able to find. Maybe they've been a hair too low this whole time, but as the soil dried up it became more concentracted with H+?

No telling...

 

[whythefnot]

Turns out my pH meter needed to be re-calibrated, it was high by about 0.4 - 0.5. So the res water was like 6.1 initially, just low enough not to help any of the problems I created... I think when I flushed and pH down'ed them heavily last month without a subsequent flush, I set up a timebomb. If the plants had never dried out, I don't think I would have had a problem -- and I normally don't let my plants dry out very much, but I kept reading that people set their blumats pretty dry so I decided to give it a shot. Probably not the smartest move in the first week of flower.

Not that running blumats on the dry side is a bad practice, but in my current situation it's not gonna work. I set the blumats up to make my soil much wetter without overflowing and things seem to have stabilized. Res is pH'ed to 6.9-7.0.

Thanks for the help, everybody. I don't want to say this thread is closed because none of this is set in stone but I haven't gotten much response and I think the worst of it is over, so I'm going to move on with my life...

Take-home lessons:
1. When doing a drastic pH adjustment in soil (why should you ever need to? welcome to my life) be sure to flush after a few days, before soil dries out...
2. Don't overdry your pots during the last 2 weeks that roots are growing. Seriously, don't.

 

[whythefnot]

I pulled out another plant to test runoff last night and it was 5.8-6.0 no matter what I did. At least I have a definitive answer about what is causing the deficiencies, and I even understand what caused my pH to drop. Now I'd just like to know what caused it to rise so high in the first place, prompting me to adjust it down so heavily.

I tried flushing with tap water @6.8pH and also tried dousing with pH 10.5 and the runoff was always the same. So I upped the res pH in a big way (~9.2) and I'm gonna leave it there for 2 days and check runoff again. Wish me luck.

 

[whythefnot]

I ended up pulling all the plants out of the tent and flushing them with plain tap water. Their runoff was consistently 5.8-5.9, wouldn't budge ... even when I ran a gallon of pH 10.5 through the soil (used about half my small bottle of pH up on 8 gallons of water). I thought that was pretty weird. But I brewed up some tea and applied it to them today, and that was enough to bring their pH up to a point where the runoff was 6.1-6.2. I'll keep a close eye on them for the next week or so and keep updating on what the hell happens next.

NEVER buying Ocean Forest again. UGHH...

 

[GoonSaibot]

You could mix ocean forest with lime next time... you ever run happy frog?

 

[whythefnot]

You could mix ocean forest with lime next time... you ever run happy frog?

I sure haven't.

The initial problem was that the Ocean Forest had too MUCH lime, and after their final transplant into the smart pots it took 2 - 3 weeks for them to start showing identifiable symptoms of high pH. I adjusted them pretty severely because it was already time to put them in flower, and I needed them to be healthy as they went into flower. I flushed them (runoff pH wouldn't budge from the high range), and hit them with pH 3.5 water in order to get their runoff down to the 6.5 - 6.8 range from 8+. That worked really well, and I gave them a final application of fungal compost tea just to be sure, and let them dry out for the next 10 days or so. They looked really good at that point, and they were a little bigger than I wanted them to get, so I flipped the lights on them.

Then I decided to install the blumats. That could have been part of the problem, but I'm doubting that now. It might have been bad timing, and really confuses me.

More likely, this deficiency coincided with the end of their first week of 12/12 and the beginning of bud formation. I think their pH had been quite low for a long time, but they didn't have any huge demands for P or K or Ca/Mg for that matter (I see all these deficiencies here, and maybe some Mo too). When they entered flower and couldn't get any of this stuff from their roots in the quantities they needed, they started drawing it from the leaves. I think that pretty much explains everything.


So, in the end, I applied a high pH solution to my plants for a day, then flushed with roughly 10 gal each (took FOREVER), then applied a naturally higher pH compost tea diluted 1:1, which raised runoff to the 6.1 - 6.2 range (nothing I tried raised it higher than that). I also gave another gallon of a different soil to each plant as a top dressing, and repositioned and re-adjusted the blumats. Hopefully this soil is settled now. I'm going to continue with diluted compost teas regularly through the rest of the grow.



It's all in the grow journal if anyone wants more perspective.

 

[whythefnot]

I have almost a year of hindsight on this issue now. As far as I can tell the original issue was caused by taking the plants from a room with very low lighting to a room where they were blasted with light, without cutting the lights back. It caused some root (rot) issues, which led to pH issues in soil. Now I'm using LEDs in veg to increase intensity and I haven't come close to having the issue again. I've been able to reproduce this effect across multiple different strains in multiple soil mixes.

 

[Peripheral]

you definitely had a p def... If you get that early enough, it will kill your yield and its very hard to recover from..

Make sure you hit em early with enough p..

 

[whythefnot]

you definitely had a p def... If you get that early enough, it will kill your yield and its very hard to recover from..

Make sure you hit em early with enough p..

If you read through the post you'll see that it didn't have anything to do with an actual deficiency of nutrients. If anything my soil was too rich.

It was lockout.