Calcium def? Or nothing at all.

[The Iconoclast]

I've scoured all the nutrient deficiency threads and the only thing that looks like it could be possible is a calcium deficiency, but it's so randomly distributed and every leaf that doesn't have it, which is almost all of them, look like perfect specimens of heath in every way.

All I'm showing is some small spots that look like copper, ie they seem to have a metallic sheen.

There's alway been one to two leaves like this right from when it was just a couple of weeks old. You'd never notice it at all with a casual look or even a longer look, all you'd see it a perfectly healthy plant.

It's puzzling because it can appear anywhere, on an old leaf, mid leaf or a relatively new leaf. Again I want to emphasise that it's affecting such a small amount of leaves that you'd never see it unless you tried to find it.

This is a hydro set up using General Hydroponics Flora Series. No other additives. I've been using tap water, but since last week I've changed to my rainwater tank but that is not relevant because this has been there from the off.

pH has been around 5.9 but I've recently raised that to 6.1 I knew the pH is accurate. ppm early on was 200 for first week then up to 500, last change it was 940 the plant used up about 250ppm of that in a few days. Transpiration seems good, canopy temps are a couple of degrees cooler than the ambient temp.

I feel pretty certain that if this is anything to worry about that it could only be nutrient deficiency if it's anything. GH is good stuff and because it's hydro and I put fresh solution in every week, I don't see why there should be any deficiency because all the other parameters are good, i.e. pH and GH seem to know what they are doing.

Here's a shot of some lower older fan leaves I removed yesterday for better air flow, and as you can see they are perfect right to the tip of the tip. How could this be a deficiency that's been there from the beginning when 99% of the leaves are perfect? I find this very very puzzling, which leads me to wonder is this anything at all.

I did not spill any drops of water or anything on the leaves. Is it possible that for some inexplicable reason calcium deficiency can just show up in a few random leaves anyway no matter how good everything is?

There's no other signs of anything, no yellowing not edge damage nothing strange, just these occasional random small copper spots

Is this nothing at all, or is it something. It has not improved since I first saw it on one early leaf and it is not getting worse. Should I just do nothing and keep a close eye on it. I don't want to dose it with extra calcium for no reason. So I'm guessing that maybe I should do nothing at this stage and just watch and wait, but I'd be happy to get some opinions.

OK so I have supplied some shots of leaves and canopy looking wonderful and perfect, and then there are the shots of the hard to find leaves showing the problem.

My question is basically should I just ignore this unless I get some more signs. I really don't want to do anything just for the hell of it.

I have never seen deficiency symptom that is part of a perfectly healthy plant.

 

[GoAuto6]

I would start by getting my pH to 5.5, could be a lock out not s deficiency.

 

[The Iconoclast]

That's one of the things that I find puzzling in that most good condition DWC I've seen were running at around 5.8 and that's pretty much what I've been running at up until a couple of days ago. The reason I raised it to 6.1 is that I could see that Mg Ca and Fe all seem to get locked out when pH it too low. And that the pH of 5.8—5.9 seems to be within what is recommended ie 5.5 to 6.5

So you seem to be implying that it is some sort of nutrient deficiency however it has occurred rather than nothing at all.

 

[GoAuto6]

I've always had beat luck at exactly 5.5 give a point either way. But every room is different and you know your room better then any one.

 

[The Iconoclast]

So when you say 5.5, you're talking hydro, yeah? I'm changing the reservoir in two days so I won't bother to adjust this current solution but l'll do the next one at 5.5 maybe it's just this particular OG Kush, seed stockers do say it's prone to humidity problems and is slightly tricky strain. 5.5 is still in range so I guess I'll do that and keep a watchful eye. At least by dumping the nutrient every week in hydro I can be pretty confident that if anything changes it won't be because of residual stuff in the soil.

 

[The Iconoclast]

I've decided to go back to tap water because the low ppm in the rainwater causes erratic readings for the pH. I'll just keep the rainwater with the low ppm for the final RO which is when I need a low ppm.

Meanwhile my meter was out by .1 not that that would be critical. I'm topping up with 5.5 adjusted tap water now and will give the 5.5 pH a go to start the next week off.

 

[Mr Green Fingers]

Get some calmag and start adding to the res and you will be golden, I would leave your PH at 6.1 as well personally because as you say ca and mg are absorbed better in hydro at that level, just keep an eye on new growth as the affected leaves won't recover

 

[The Iconoclast]

I've just given her a major defoliation. I have morphed into a defoliation whore. These leave definitely won't recover.

 

[Waira]

... well in hydro, you know how fast things can happen! Even a brief pH drift can trigger symptoms that halt-start in fits,... those are odd manifestation symptoms, with that black color, not typical, but I'd lean toward Ca defc., with P defc. as a more remote possibility,... Tops have signs of minor light intensity stress, how close are they? This can trigger Ca defc symptoms, and increase demand in general.... If the pH has been solid, steady, then tinker with the nutes to get a little extra P and Ca in there..
As for defoliation, unless you're doing it for light/air movement reasons, don't take affected leaves off, it won't help or stop anything.....likely make matters worse!
Rainwater is wacky for pH'ing because unlike tap water, there's not pH buffering minerals in there (CaCO3),.. it's the carbonate that's involved with pH buffering,... even in certain tap water, the Ca may be present, but not in ionized/available form that the plant can take up,.... as such, even small inputs can cause wild pH swings; it's why taking the pH of RO/Di water (even rain water if collected very cleanly) is pointless, because of the way that pH meters work.....

 

[The Iconoclast]

@Waira Yeah I've gone back to tap water, and will only use the rain water now for the final flush because it's better for RO, having only 30ppm in it. I also think I cannot get an accurate pH reading for rainwater due to there not being enough ions in the water. And for the other reasons you have stated.

You're right about things happening quickly, I removed a whole bunch of leaves, seedstockers say that this plant is prone to humidity problems, but stripping all the big fan leaves even the ones on the bottom that are in good condition was just me trying out the defoliation technique. So now all the affected leaves are gone, but that was just a happy bonus from defoliating.

Right after I removed all those leaves, I finally saw my first pre pistil so I'm glad I did the defoliation. I'm not going to give it any supplements yet because now that the plant is devoid of problem leaves, I will be keeping a very close eye on it and if I see this return then I'll know it's the same problem returning rather than a past problem that is fixed.

This is because I am refreshing the nutrients today, so that resets everything. I'll probably get a bottle of cal/mag and have it on hand, if I see anything suspect I'll use it. If it is possible, I really would like to grow this first auto, with no added anything except the GH Flora, the reason for this is that, if I do anything different on the next grow then I'll have a baseline to compare with. Hope that makes sense. Last mix of the Micro/Grow/Bloom was in the ratio of 3/3/4, but for the transition I've upped that to 3/3/5

But I appreciate that the consensus seems to point to Cal, and not anything else. Thing is I saw a copper spot on one of the very early baby leaves, so if I ever see it again on a future grow, I'll add the cal straight away then see what happens.

Finally the tap water was 7.1 and the GH nutrients automatically buffered it to 6.5, I'm going to take it down slowly to maybe 6.3, and leave it there for a little while. The reason for this is that according to the charts, slightly higher rather than slightly lower pH is better for calcium absorption. Plus my first hydro grows 25 years ago, were all at 6.3 and I never had any problems with any nutrient deficiency. That was growing both a solid indicator which I think was a cali redbud but I can't be sure because it was a clone, and also a taller more slender sativa dominant Dutch Hope. I'm going to go with my gut here and if it doesn't go well then I'll follow the general advice about taking hydro lower than soil, but sometimes and man's gotta do what a man's gotta do.

If something goes wrong then I only have myself to blame and I can live with that and adjust next grow, after all, no one is going to die. I'd rather be wrong and blame myself, than follow someone else's advice if my gut reaction and prior direct experience tells me otherwise and then blame them. Because blaming other people for your own decisions is not the way that I play the life game.