Plant Problem Quiz

Renfro

Renfro

Well-Known Member
Ok folks, thought this would be fun. I have a plant that has a problem. I have already pinpointed the issue and corrected it to achieve healthy growth. I am posting this as a little quiz to see how many people can get it right. No prizes or awards, just bragging rights.

So here it is, information typical of what is provided here to diagnose plant problems:

Other plants of the same age and situation are healthy

Strain Mimosa
Medium Mills DNA Coco Cork in 10 gallon pot with good drainage
Feed GH Flora 3 Part with Armor Si and Calimagic, same feed the other plants get and this cut has had before without issue.
Feed pH 6.3 - 6.5 again same as the other plants get and this cut has had before without issue.
Water is Reverse Osmosis PPM = 2
Tribus Original
PPM 1000 - 1050 @ 0.5 conversion
Watering is done when coco is in the middle of the green part of a moisture meter (not dry but not saturated), watered to achieve 20% runoff.
Lighting 1000 Watt DE CMH 18/6 284 umols at that plants canopy
Temperature 79 - 81F Canopy
Leaf Surface Temperature 77.5 Measured on healthy new growth just above the node with the leaf pictured.
Humidity 45 - 50%
Plant is not the tallest and not closest to any fans
Plant was cut (cloned) on 8/6/2019
Plant has been topped for clones and pruned pretty hard, not cleaned up at all.
No foliar applications

Here is a typical affected leaf

20191127_235923.jpg

Leaf Surface Temp (when room is at 81F)

20191128_000313.jpg

Light intensity at that plants canopy

20191128_000129.jpg

Here is a shot of the plant doing better now on the new growth (it's the one more to the left obviously lol)

20191128_000153.jpg

Here is a shot of the node above the affected one, now that the plant is doing better

20191127_235951.jpg

So folks, what are your guesses as to the cause of the curling at the leaf margins?

I will NOT tell the correct answer or provide any more information until Sunday night. That will give everyone time to make their guesses.
 
Last edited:
Nutty sKunK

Nutty sKunK

Well-Known Member
Well looks like the humidity was out of whack you say it’s fine.

I say the roots where getting too warm. Deffo looks like a transpiring issue.

Nice to see a plant fixed!
 
MickFoster

MickFoster

Well-Known Member
Your pH is off for coco......should be around 6.0 and coco should be fed at least twice daily at a lower nute strength for plants that large. Failure to feed daily and allowing it to become even a little dry will result in salt build up in the root zone.....also daily feedings to run off provides fresh oxygen to the roots.
 
Renfro

Renfro

Well-Known Member
It looks like we have all the responses we are gonna get so I will go ahead and post the answer.

For starters, I did note in the OP that this cut and others have found this feed and target pH desirable. I started lower when I first got this coco and they were unhappy, raising the pH made them happy. Perhaps it's the cork as I have always run coco lower around 5.8 - 6.1.

Quiz 1 Answer

Answer: Low pH at the root zone.

Despite being fed at a proper pH range with adequate runoff, the media has acquired a much lower pH. A soil pH test at several spots on that plant yielded results between 4.8 and 4.9.

I suspect this was due to a large population of beneficial bacteria excreting organic acids. I do multiply my own Tribus original and use it very generously. I likely applied it before it had time to consume most of the sugars used for multiplication therefore it continued to multiply rapidly in the root zone, excreting organic acids and causing the pH to crash.

The solution was to mix up a special feed at 8.1 pH. This is the only change that was made, pH corrective feeds.

The plant responded quickly as the pH after that feed swung through down the ideal pH range settling at a pH of 5.8, much higher than 4.8! The subsequent feed was at 7.1 and the media settled at 6.3. We have knocked the coco pH back inline lol.

This is a good example of how pH issues don’t always show up the same way. Without being able to accurately check the pH of my root zone I would not have been able to diagnose and correct this problem.

Many people have probably already hear me preach the benefits of having a reliable soil pH meter. They can read liquids too so if you are just going to get one pH meter I suggest boning up for one with the soil probe. I will list some models that I own and use at the bottom of the page.

Slurry tests and runoff tests are not reliable. If one absolutely must use one of these techniques, then I recommend a slurry test that should always be conducted with distilled water. I would say that with this being more time consuming and messy (especially with lots of plants) I would personally check the pH less often and that's not good.

I should also note that the cheap analog soil pH meters are terrible. They aren’t even close.

I have made checking the pH of my root zones (all of them as they react differently) a much more frequent thing, daily generally. Being proactive instead of waiting for problems to arise keeps the plants much happier. I believe this to be more imperative in flowering as that growth is the real deal final answer.

This has proved to be the solution to the mystery of why random plants would shit the bed and not do as well as others. This is an issue I hadn’t seen growing in DWC because of the lack of a medium to buffer the root zone. Simply monitoring the nutrient pH was enough for these methods of growing.

Soil pH meters that I have, in the order of how much I like using them:

Apera https://aperainst.com/ph60s-premium-spe ... il-canning
Bluelab https://www.getbluelab.com/shop/By+Cate ... H+Pen.html
Hanna https://www.hannainst.com/groline-soil-ph-tester.html
 
PadawanWarrior

PadawanWarrior

Well-Known Member
Renfro said:
It looks like we have all the responses we are gonna get so I will go ahead and post the answer.

For starters, I did note in the OP that this cut and others have found this feed and target pH desirable. I started lower when I first got this coco and they were unhappy, raising the pH made them happy. Perhaps it's the cork as I have always run coco lower around 5.8 - 6.1.

Quiz 1 Answer

Answer: Low pH at the root zone.

Despite being fed at a proper pH range with adequate runoff, the media has acquired a much lower pH. A soil pH test at several spots on that plant yielded results between 4.8 and 4.9.

I suspect this was due to a large population of beneficial bacteria excreting organic acids. I do multiply my own Tribus original and use it very generously. I likely applied it before it had time to consume most of the sugars used for multiplication therefore it continued to multiply rapidly in the root zone, excreting organic acids and causing the pH to crash.

The solution was to mix up a special feed at 8.1 pH. This is the only change that was made, pH corrective feeds.

The plant responded quickly as the pH after that feed swung through down the ideal pH range settling at a pH of 5.8, much higher than 4.8! The subsequent feed was at 7.1 and the media settled at 6.3. We have knocked the coco pH back inline lol.

This is a good example of how pH issues don’t always show up the same way. Without being able to accurately check the pH of my root zone I would not have been able to diagnose and correct this problem.

Many people have probably already hear me preach the benefits of having a reliable soil pH meter. They can read liquids too so if you are just going to get one pH meter I suggest boning up for one with the soil probe. I will list some models that I own and use at the bottom of the page.

Slurry tests and runoff tests are not reliable. If one absolutely must use one of these techniques, then I recommend a slurry test that should always be conducted with distilled water. I would say that with this being more time consuming and messy (especially with lots of plants) I would personally check the pH less often and that's not good.

I should also note that the cheap analog soil pH meters are terrible. They aren’t even close.

I have made checking the pH of my root zones (all of them as they react differently) a much more frequent thing, daily generally. Being proactive instead of waiting for problems to arise keeps the plants much happier. I believe this to be more imperative in flowering as that growth is the real deal final answer.

This has proved to be the solution to the mystery of why random plants would shit the bed and not do as well as others. This is an issue I hadn’t seen growing in DWC because of the lack of a medium to buffer the root zone. Simply monitoring the nutrient pH was enough for these methods of growing.

Soil pH meters that I have, in the order of how much I like using them:

Apera https://aperainst.com/ph60s-premium-spe ... il-canning
Bluelab https://www.getbluelab.com/shop/By+Cate ... H+Pen.html
Hanna https://www.hannainst.com/groline-soil-ph-tester.html
Click to expand...
Hey at least I was right when I said I knew I was gonna be wrong, haha. I just didn't think you would get the ph wrong, let alone have any kind of bug issue like I answered, so this was a tough quiz coming from you, lol.
 
Kushash

Kushash

Well-Known Member
Renfro said:
Ok folks, thought this would be fun. I have a plant that has a problem. I have already pinpointed the issue and corrected it to achieve healthy growth. I am posting this as a little quiz to see how many people can get it right. No prizes or awards, just bragging rights.

So here it is, information typical of what is provided here to diagnose plant problems:

Other plants of the same age and situation are healthy

Strain Mimosa
Medium Mills DNA Coco Cork in 10 gallon pot with good drainage
Feed GH Flora 3 Part with Armor Si and Calimagic, same feed the other plants get and this cut has had before without issue.
Feed pH 6.3 - 6.5 again same as the other plants get and this cut has had before without issue.
Water is Reverse Osmosis PPM = 2
Tribus Original
PPM 1000 - 1050 @ 0.5 conversion
Watering is done when coco is in the middle of the green part of a moisture meter (not dry but not saturated), watered to achieve 20% runoff.
Lighting 1000 Watt DE CMH 18/6 284 umols at that plants canopy
Temperature 79 - 81F Canopy
Leaf Surface Temperature 77.5 Measured on healthy new growth just above the node with the leaf pictured.
Humidity 45 - 50%
Plant is not the tallest and not closest to any fans
Plant was cut (cloned) on 8/6/2019
Plant has been topped for clones and pruned pretty hard, not cleaned up at all.
No foliar applications

Here is a typical affected leaf

View attachment 4428164

Leaf Surface Temp (when room is at 81F)

View attachment 4428170

Light intensity at that plants canopy

View attachment 4428172

Here is a shot of the plant doing better now on the new growth (it's the one more to the left obviously lol)

View attachment 4428173

Here is a shot of the node above the affected one, now that the plant is doing better

View attachment 4428174

So folks, what are your guesses as to the cause of the curling at the leaf margins?

I will NOT tell the correct answer or provide any more information until Sunday night. That will give everyone time to make their guesses.
Click to expand...
This post helped me tremendously.
I've been struggling with an issue this grow.
Upper fan leaves developing blotches. Strange color blotches not yellow more like an off color green in various locations on the upper fan leaves.
Some leaves appeared light stressed. Overall leaves were on the dull side.

The key for me that made me suspect the PH of my soil was the appearance of lower leaves taking on the stressed lifting edges. Something that would not happen with real light or heat stress but appeared on mine and on yours also from what I can see.

I had been adding very small amounts of lime to each soil mix being used over and over for years.
The last two mixes of 40 gallons of soil only received 1 1/2 cups of dolomite lime.
I know this is a small amount of lime but I erred on the side of less not knowing how much a re amended soil would need.
After I saw this thread it clicked that I likely needed lime.

I added some 3 days ago to half of my plants and felt I could see an improvement so I added lime to the rest.

I'll leave room to say I'm wrong and have confirmation bias but I'm feeling pretty good about it and have a feeling my plants are going to perk up in a week or two just in time to switch to 12/12.

If I saw this post in November I would have guessed stress or mites, never thinking it was a low PH.

Enjoy your break!
 
rustyshaclkferd

rustyshaclkferd

Well-Known Member
Renfro said:
It shows how even when you are feeding at the correct pH the medium can acquire a different pH.
Click to expand...
Hell even if you use the same lines or equipment ...emiter, pressure regulators, filters everything can change from tank to spout. Always check feed, at plant, and after(runoff) for pH variances.

Good read
 
OldMedUser

OldMedUser

Well-Known Member
Renfro said:
Soil pH meters that I have, in the order of how much I like using them:

Apera https://aperainst.com/ph60s-premium-spe ... il-canning
Bluelab https://www.getbluelab.com/shop/By+Cate ... H+Pen.html
Hanna https://www.hannainst.com/groline-soil-ph-tester.html
Click to expand...
I didn't even know they made such things. Think I'd go for the Hanna. Half the price and if it works as good as my 27 yo Hanna TDS pen should do me fine. Pretty sure my Hindu Kush has pH issues tho the runoff came in at 6.4. Gave her a good feed yesterday at 5.7. Promix with some added organics. Looking like low P but she's been fed well the last two waterings.

:peace:
 
Nutty sKunK

Nutty sKunK

Well-Known Member
OldMedUser said:
I didn't even know they made such things. Think I'd go for the Hanna. Half the price and if it works as good as my 27 yo Hanna TDS pen should do me fine. Pretty sure my Hindu Kush has pH issues tho the runoff came in at 6.4. Gave her a good feed yesterday at 5.7. Promix with some added organics. Looking like low P but she's been fed well the last two waterings.

:peace:
Click to expand...
Ca, Cu, Fe and K antagonise P so I’d look at them before adding anymore.

Or as u say could simply be a pH issue.
 
OldMedUser

OldMedUser

Well-Known Member
Nutty sKunK said:
Ca, Cu, Fe and K antagonise P so I’d look at them before adding anymore.

Or as u say could simply be a pH issue.
Click to expand...
I'm leaning mainly towards pH being it's problem. I was away in BC for almost 3 weeks and the wife was just giving it RO water. I had just repotted from a 1gal to a 7gal 2 days before I left. I added a couple cups each of steer, sheep manures, same of earth worm castings and a light dose of Mega Crop to ProMix HP. Also put some flower myco I got at a local greenhouse in the hole before dropping the plant in. Left it vegging under a 400W Philips CMH.

I also decided to water it once with my unfiltered dugout water thinking that it has natural myco and minerals in it. I pHed it down to 7 from 8.4 then soaked it in. May have tossed everything off but not sure. Pretty hard water around 400ppm.

When I got back on the 4th she was looking a bit rough. Just gave her water at first then I fed her a half strength dose of AN 3-part with a half dose of Big Bud. Swapped the light out for one of the new 600W Hortilux SHPS lights I got in BC too. On the 11th I flipped her to flower with a light dose of nutes and a full dose of BB. Still getting crappy looking leaves that were easy to pull off and some dropping. Mostly older fans.

Two days ago I mixed up a batch with Mega Crop, Calmag, some Green Leaf P/K instead of BB, good dose of Bud Factor X.

Exact dosage into 7L of RO was 10ml CalMag first. 5g of Mega Crop, 14ml Bud Factor X, 2g BigUp 0-52-34, 2ml SuperThrive, 2g Carbo which is GreenLeaf dextrose. Was going to use blackstrap molasses but wanted to get it done. I dumped the first batch I made as I'd added a tsp of Aluminum Sulfate to lower the pH. Worked too good and the pH came out at 3.3! I added 9ml of Rhino Skin to raise the pH and that didn't help so added 25ml, 5ml at a time of pH Up and still only got it up to pH 4.2 then it all started to flocculate so I dumped it than remixed the same batch without the Al2(SO4)3. Came out at 5.7 so I gave her that. After it had soaked in and I removed the runoff an hour later I added a bit more water the next morning to force some more runoff and it tested at 6.2. Seems like it should be good so WTF I'm asking myself.

Budding seems very slow and a few days ago I noticed that my timer was set for slightly over 13 hours on so reduced it to 12/12. Here's a pic I took last night after light's out with the flash. I made it a bit higher rez that I usually post so you can see the leaves clearly. 18 days since the flip.

SadHindu29121901.JPG

I'm usually the guy helping peeps figure this stuff out and it's got me stumped. Wanted a good yield off this one to make more RSO for the wife. She's going thru 3g a week now and increasing dosage faster than I thought she could as she hasn't used pot in over 15 years. Still have lots of older pot and stuff in the freezer to make more so it's not critical but annoying as hell. :)

:peace:
 
OldMedUser

OldMedUser

Well-Known Member
Renfro said:
its a pos I never use it you can have mine. it's a POS Apera (fast) or Bluelab (slow)
Click to expand...
Why does the old adage always seem to hold true. You get what you pay for. lol

Is it just craply made or that and not very accurate?

I figure I can do fairly accurate runoff tests or even punch a hole in the lower section of the plant pot and extract a sample to do a slurry test with distilled, de-ionized water and freshly calibrated pH pen. The lower third of the soil is where most of the action is regarding things like pH and/or root issues.

Thanks for the offer tho Renfro.

:peace:
 
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