Strange issue - necrotic stripes on leaves - PH? K def? Mag def? Nutrient burn?

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EasyCheesy

EasyCheesy

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I'm hoping someone can help me.

I've got 6 Ugorg#1's in 10L coco/perlite hempy buckets They're in week 5 of flower. I'm feeding them Canna Flores hard water nutrients at around 1.1 EC. This includes my base tap water EC, which is around .6 and around 7.8 ph. So they're not being fed a large amount - WAY lower than the feed chart, and they're big plants. They were vegged for around 8 weeks, most of which was in little 1L coco/perlite mini hempy pots under a T5, watered every day always with run off. They were perfectly happy during veg. I moved them into the flower tent (450w qb) and into the 10L pots. I was watering every 2/3 days (always with run off) until I saw the roots hit the res, and from then on then on I was watering when the coco felt 'light' and the plants were just starting to wilt a tiny bit (basically following soil watering methods, the wrong move now, I know). I defoliated them and flipped them to flower once I saw the roots had reached the res and then a week or two later I started to see some weird issues popping up. These are pics from that time -

20210705 021956
20210705 022051
20210705 022041


It immediately looked like PH issues to me, so I checked my PH pen calibration and flushed the plants with plain ph'd water then refed with a light feed. Seemed to help a bit but I was still seeing a few of the same issues a week later, so I flushed again. This time I checked the runoff PPM at the start of the flush and it was pretty close to what was going in, so no salt build up it seems. The PH coming out the runoff hole is pretty much always the same as the PH going in, as you'd expect with hempy buckets. After the second flush it did seem to calm right down, although I think I also backed the lights off a bit at this point too. They've been growing well since then, but as I was working the ec up into flower I think I reached about 1.2ec (including my hard waters base .6ec) and I started seeing some tip burn so I've backed it off to around .9ec, but now I'm seeing this issues popping up again. A recent pic -

20210726 235504

20210726 225507


So it seems to get worse then feed is reduced, and the lights get closer. Seems like a standard deficiency I guess? The thing is they really don't look underfed, they're a very rich green and they've got a bit of tip burn, and I'm scared to up the feed in case I burn them badly. Here is a pic of the one of the actual plants a few days ago (D29 F) for context, and a bud pic just because :) -

20210724 235327
20210724 235359


So far I've seen these necrotic stripes attributed to -

K Def
Calcium Def
Mag Def (my water is hard but high in cal but not mag, and I'm using hw nutrients, so this could make sense, I did add a teaspoon of epsoms the other day but I can't say if it's made a difference to be honest)
Light Burn
Wind burn
Nute burn

Sigh.

A nutrient deficiency seems very possible considering the low EC I've been giving them (although calcium def feels unlikely with my 300ppm water that's high in caco3). It's strange that they were taking the full strength veg nutes fine though and showing tip burn at like 1/4-1/3 strength flower nutes. Perhaps it's the much larger pot/res size.

I also wondered if the issues were caused by letting the coco get too dry between waterings (only the very top was dry, but it was noticeably light) but I've upped the watering frequency and it doesn't seem to have helped.

Wind burn is also possible as I have three oscillating fans in there and they're quite strong. If this is all due to windburn I will kick myself!

I'm really hoping I can get some advice as I've still got a good month of flower left and I don't wanna mess it up. It's my first grow with synthetics and first time using coco and hempy buckets.

Any ideas anyone? @Aqua Man I hope you don't mind me tagging you in?

Thanks!
 
EasyCheesy

EasyCheesy

18
3
Bring your pH down to about 5.5. You are in coco, not soil.
Lockout.

Thanks. I should've mentioned I'm PHing to 5.8-6. The PH coming out the drain hole is never further 0.2 away from what's going into it whenever I've checked. You think I should bring it right down to 5.5? I'll give it a go next watering. Cheers.
 
ComfortablyNumb

ComfortablyNumb

4,369
263
Sorry, where did you get 7.5 from? My tap water is around 7.8, I add nutrients which brings it to around 6.3, then I use PH down to get it to 5.8-6.
Sorry, that was the only pH number I saw in your post and I guessed it was your current pH. My bad, I was reading too fast.
 
ComfortablyNumb

ComfortablyNumb

4,369
263
Since you are in coco, I doubt a root issue. That makes me even more towards pH. It could be a missing nute, but lets check the other things first so we don't use the wrong treatment.
What are your ppms in and out each feeding?
 
EasyCheesy

EasyCheesy

18
3
Since you are in coco, I doubt a root issue. That makes me even more towards pH. It could be a missing nute, but lets check the other things first so we don't use the wrong treatment.
What are your ppms in and out each feeding?
My starting water tap water is around 250-300ppm and the feed takes it up to about 800 (although the last feed was probably closer to 600). Low (as I understand it) for good sized plants in week 5 of flower. I don't check the runoff PPM/PH as often as I should, but whenever I do it's always very close to whatever's going into it, as you'd expect with coco/perlite hempy buckets. I was wondering about calcium carbonate build up on the roots from my hard water, so I made sure I did both flushes with RO water (buffered with a bit of hard water and the appropriate amount of calmag) then gave them a weak feed straight after, in an attempt to shift some of that limescale if that is in fact the issue. The issue did seem slow down after the flushes, but looking back I think it was only after I scaled up the feed, and then I saw tip burn and backed the feed off I'm seeing it start to pop up again.

The thing is if you look at those last few pics they are a rich green, they don't look underfed, but I'm not feeding them a lot... I am wondering if the canna flower nutrients are just bit low in P and K and a bit high in N for this stage of flower (they want people to buy the PK booster after all). I've ordered a cheap low N salt based fertiliser that will work for this purpose - Chempak 8 (cue horrified gasps as I use industrial fertiliser on my expensive limited edition seeds). I'm going to try them on that for the next feed I think, still keeping the ec at the low end, and see how they react.

I know if I back the lights off far enough the issue will probably stop, but I resent having to do that when I know I can get maximum bud density/quality from all those lower down nugs by getting the light in closer like it is now - it's not ridiculously close by the way, about 18 inches, exactly what's recommend for flower for this model.
 
ComfortablyNumb

ComfortablyNumb

4,369
263
Before you add the evil costly industrial stuff, Get a bottle of Ammonia, fill just the bottom of a small bowl and set it in the tent.
Ammnoia is nitrogen. Let the plant try transpiration before you dump toxic lunches on it.
 
Flexnerb

Flexnerb

1,294
163
I'm hoping someone can help me.

I've got 6 Ugorg#1's in 10L coco/perlite hempy buckets They're in week 5 of flower. I'm feeding them Canna Flores hard water nutrients at around 1.1 EC. This includes my base tap water EC, which is around .6 and around 7.8 ph. So they're not being fed a large amount - WAY lower than the feed chart, and they're big plants. They were vegged for around 8 weeks, most of which was in little 1L coco/perlite mini hempy pots under a T5, watered every day always with run off. They were perfectly happy during veg. I moved them into the flower tent (450w qb) and into the 10L pots. I was watering every 2/3 days (always with run off) until I saw the roots hit the res, and from then on then on I was watering when the coco felt 'light' and the plants were just starting to wilt a tiny bit (basically following soil watering methods, the wrong move now, I know). I defoliated them and flipped them to flower once I saw the roots had reached the res and then a week or two later I started to see some weird issues popping up. These are pics from that time -

View attachment 1150707 View attachment 1150709 View attachment 1150708

It immediately looked like PH issues to me, so I checked my PH pen calibration and flushed the plants with plain ph'd water then refed with a light feed. Seemed to help a bit but I was still seeing a few of the same issues a week later, so I flushed again. This time I checked the runoff PPM at the start of the flush and it was pretty close to what was going in, so no salt build up it seems. The PH coming out the runoff hole is pretty much always the same as the PH going in, as you'd expect with hempy buckets. After the second flush it did seem to calm right down, although I think I also backed the lights off a bit at this point too. They've been growing well since then, but as I was working the ec up into flower I think I reached about 1.2ec (including my hard waters base .6ec) and I started seeing some tip burn so I've backed it off to around .9ec, but now I'm seeing this issues popping up again. A recent pic -

View attachment 1150711
View attachment 1150710

So it seems to get worse then feed is reduced, and the lights get closer. Seems like a standard deficiency I guess? The thing is they really don't look underfed, they're a very rich green and they've got a bit of tip burn, and I'm scared to up the feed in case I burn them badly. Here is a pic of the one of the actual plants a few days ago (D29 F) for context, and a bud pic just because :) -

View attachment 1150712 View attachment 1150713

So far I've seen these necrotic stripes attributed to -

K Def
Calcium Def
Mag Def (my water is hard but high in cal but not mag, and I'm using hw nutrients, so this could make sense, I did add a teaspoon of epsoms the other day but I can't say if it's made a difference to be honest)
Light Burn
Wind burn
Nute burn

Sigh.

A nutrient deficiency seems very possible considering the low EC I've been giving them (although calcium def feels unlikely with my 300ppm water that's high in caco3). It's strange that they were taking the full strength veg nutes fine though and showing tip burn at like 1/4-1/3 strength flower nutes. Perhaps it's the much larger pot/res size.

I also wondered if the issues were caused by letting the coco get too dry between waterings (only the very top was dry, but it was noticeably light) but I've upped the watering frequency and it doesn't seem to have helped.

Wind burn is also possible as I have three oscillating fans in there and they're quite strong. If this is all due to windburn I will kick myself!

I'm really hoping I can get some advice as I've still got a good month of flower left and I don't wanna mess it up. It's my first grow with synthetics and first time using coco and hempy buckets.

Any ideas anyone? @Aqua Man I hope you don't mind me tagging you in?

Thanks!
Just to let you know any additions of Mg wo t be seen in new growth right aeay. It takes upto 5 weeks of a shortage of Mg to even show up. So when it does you are 5 or so weeks behind. Im not a coco guy but i have read some threads. My guess is they werent getting enough food n watering every 2 to 3 days doesnt cut it with coco. @Aquaman would be able to help ya....peace ill follow along
 
Aqua Man

Aqua Man

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Drop these and check back after I'm done driving. Absolutely likely it's allowing to much dry back. Coco should stay wet brother. Always remember COCO is far more like hydro than soil. With these 3 threads you should have almost everything you need for coco. I'll add a 4th that will help understand the differences in media and pots and how the water table is different.




Extra.


Ok check backnin about an hr or 2
 
EasyCheesy

EasyCheesy

18
3
Before you add the evil costly industrial stuff, Get a bottle of Ammonia, fill just the bottom of a small bowl and set it in the tent.
Ammnoia is nitrogen. Let the plant try transpiration before you dump toxic lunches on it.
Ammonia in the tent? What do you mean? I think the canna feed might have too much N, what will ammonia do to help that?

I'm sure I'll get stick for this, but I don't think there's any issues with chempak that don't exist with any salt based fertiliser - it's just a normal salt based dry amendment fertiliser, the kind used by commercial farmers, the kind that is very thoroughly tested for heavy metals and contaminants because millions of ££ worth of commercial hydroponic food crops depend on it. Most likely it contains the exact same minerals that are suspended in the water I'm currently paying for with my Canna nutrients, except that it's dry, 1 part, and a £10 box makes 2000 gallons of high strength nutrient mix. I liked the look of it because it's a) the right N.P.K ratios and b) contains very little calcium but does contain mag, which is perfect for my high Caco3 hard water, and c) it's cheap obviously. Oh and I've seen great results from other hydro grows using only chempak.

I've only been growing for a couple of years, but I've gotten that point now (that we probably all get to) where I actively avoid any growing nutrients/supplements marketed directly to cannabis growers, because I've noticed that if those products are actually needed they will be available in commercial agriculture for literally a fifth of the price. I don't believe there's a magic nutrient or supplement that cannabis requires that no other plant does.

Just to let you know any additions of Mg wo t be seen in new growth right aeay. It takes upto 5 weeks of a shortage of Mg to even show up. So when it does you are 5 or so weeks behind. Im not a coco guy but i have read some threads. My guess is they werent getting enough food n watering every 2 to 3 days doesnt cut it with coco. @Aquaman would be able to help ya....peace ill follow along

Ok thanks... I thought mag def was a fairly quick fix. If it is mag def, it's a VERY weird representation of mag def though right? No yellowing between veins, no yellowing AT ALL really, just those dark necrotic patches between the veins. Re: watering - I'm setting up a proper slanted drain table today so it'll be much easier to water to waste every day. I have upped the watering to daily and it doesn't seem to have made much difference though. Bear in mind after 24 hours the 10L pot is still very heavy, the coco is still soaking wet throughout and it's just the hempy 'res' at the bottom that's empty. After 48 hours they are a bit lighter but the coco is still heavy and wet throughout, and it's only after 3 days that the coco starts to get dry on top, the plants start to wilt a tiny bit and the pots feel really light. My next plan is try and up the feed a bit, but I'm nervous as they're a very rich green and they've got tip burn already.
 
ComfortablyNumb

ComfortablyNumb

4,369
263
Before you add the evil costly industrial stuff, Get a bottle of Ammonia, fill just the bottom of a small bowl and set it in the tent.
Ammnoia is nitrogen. Let the plant try transpiration before you dump toxic lunches on it.
I was joking with this "evil costly industrial stuff" by the way.
Ammonia does help when there is a lockout at the roots. It's a very temporary bandaid.
 
EasyCheesy

EasyCheesy

18
3
Drop these and check back after I'm done driving. Absolutely likely it's allowing to much dry back. Coco should stay wet brother. Always remember COCO is far more like hydro than soil. With these 3 threads you should have almost everything you need for coco. I'll add a 4th that will help understand the differences in media and pots and how the water table is different.




Extra.


Ok check backnin about an hr or 2

Thanks @Aqua Man. I have been through a couple of these already I believe, but I'll have another read through and bone up! The general consensus does seem to be 'up the watering', which I have done. However, because the issue isn't nearly as bad as it was when it first popped up, it's hard to say if more watering has helped yet.

I think the thing I find weird is that when they were in veg they were in 1L mini hempy pots, 50/50 coco/perlite with a perlite res, for SIX weeks. I watered/fed them (full strength from the canna chart) daily, and as you can imagine, by week 4 that little pot was light as feather after 24 hrs, the coco seemed really dry looking back. I didn't think anything of it at the time because they were growing really happily with no issues so I just carried on, if I'd seen any issues I'd have upped the watering shedule. It was only when I moved them into the 10L under the big LED and flipped them to flower that issues appeared (which is admittedly when I was watering every 3 days when the pots were light, which I now know is bad - although they seemed perfectly happy with the dryback in veg weirdly).
 
EasyCheesy

EasyCheesy

18
3
I also thought I saw signs of overwatering when I first moved them into the 10L's which is what made me conservative with watering moving forward, as that had never happened in the little 1L pots.

Looking back I'm sure it was just transplant shock (obviously it can look just like a typical soil overwatering - fat puffy droopy leaves and a sad plant, and I still had my soil head on). I'm not surprised they didn't love the transplant, they were in those little 1L pots for way too long while I was sexing them. I did loads of 'hempy bucket' research before starting this grow (I've been a soil/organics guy up to this point), but I didn't do enough straightforward coco growing research, clearly :D.

Also, not sure if I mentioned this, but temps have been around 26-29c, and RH has been around 55-60%.
 
Aqua Man

Aqua Man

Staff
Supporter
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I also thought I saw signs of overwatering when I first moved them into the 10L's which is what made me conservative with watering moving forward, as that had never happened in the little 1L pots.

Looking back I'm sure it was just transplant shock (obviously it can look just like a typical soil overwatering - fat puffy droopy leaves and a sad plant, and I still had my soil head on). I'm not surprised they didn't love the transplant, they were in those little 1L pots for way too long while I was sexing them. I did loads of 'hempy bucket' research before starting this grow (I've been a soil/organics guy up to this point), but I didn't do enough straightforward coco growing research, clearly :D.

Also, not sure if I mentioned this, but temps have been around 26-29c, and RH has been around 55-60%.
Yeah raise humidity and reduce lights for a few days after transplant to reduce transpirational stress.

Often times when ppl see issue with the plants they don't back the lights up and this results in a faster progression of the issue.

I think it was simply just a stability issue in the root zone between water, nutrient concentration (as the media dries and plants uptake water nutrients can become more concentrated), nutrient ratios (same deal without frequent feeding and run off)
, ph fluctuations in the media etc.

9 times out of 10 plants will make it through veg fine but once they start hauling ass on stretch you start to see the issues created by the instability of the media when not watering frequently enough with run off.
 
EasyCheesy

EasyCheesy

18
3
I was joking with this "evil costly industrial stuff" by the way.
Ah ok , my bad 🙄
You can almost be certain when you see multiple deficiencies it's not a lack of this or that.... its an uptake issue or environmental issue.
Yeah that makes sense. Do you see multiple deficiencies though? I just see that weird bronzing/browning coming in from the edges of the leaves inwards in between the veins, and a little bit of tip burn.
If I weren't feeding them so lightly (last feed was .9ec, and that's including my base water ec of .6) I'd assume it was just a bit of nutrient burn, in fact I did think that last week, which is why I reduced the feed from 1.1. to .9, but it doesn't seem to have helped.
 

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