At the end of my rope; pH and nutrient issues.

GR0WL0

Well-Known Member
I am growing Cinex in Roots Organics soil ALMOST 100% organically. Prior to this entire experience, my leaves had exhibited interveinal chlorosis and heavy ridging leading me to believe it could be a zinc deficiency. Very cautiously I added a small amount of zinc, which did seem to correct the symptoms. However, I suspect at this time something else was happening with the plant as the leaf color has never made a full return. This leads me to my current challenge to be overcame.


About three weeks ago, my plant started experiencing a few brown spots on a few leaves. I ended up falling extremely ill around this point in time and had to take care of myself and not my plant. Returning to proper health, I went to check on my plant about a week later (it was being tended to by someone inexperienced). The spots had spread to cover more of the leaf, more leaves were tainted by the spots, and the overall canopy (ScrOG) had begun to yellow again. The overall condition and especially the way the brown portions of the leaf were looking led me to conclude it was a phosphorous deficiency. So I went to the farm supply and picked up some fish emulsion with a healthy amount of phosphate, watered it in, waited, and it seemed to correct some of the yellowing—temporarily. The yellowing returned and the leaves continued to be assaulted with brown spots. Looking under the plant, which for some reason I hadn’t considered before, I noticed there was a multitude of dead, brown, crunchy leaves. What is interesting to me is that these shriveled up leaves still have green spots, which you can see on the leaf to the far right of the image. I guess somehow when the leaf died, some chlorophyll survived.


More research ensued and a feeling of hopelessness yielded me watering with a small amount of epsom salts due to suspicion of magnesium deficiency. So, watering with all these different missing nutrients has got to solve the problem, right? Well, I certainly thought so. Personally I had a hard time believing that I had ignored the needs of my plant so much as to be missing sufficient amounts of 3 different nutrients. I am not experienced in the pursuit of growing by any means, but I really thought I was consistently hitting good levels of all nutes (as my past two grows had indicated). It drained my confidence as a grower heavily, and I felt defeated. In one last attempt, I looked into pH. I had heard about nutrient lock-out before but hadn’t taken the time to research it. Reading about it, it made a lot of sense. If my soil pH was too high or too low, it wouldn’t be able to absorb the proper nutrients, thus expressing deficiency symptoms, even with ample amounts of nutrient in the soil. So I whipped out my pH test and went to work testing my water and runoff. The runoff pH was a a decent bit lower than my water, indicating the actual pH of the soil to be EVEN LOWER. My pH test kit only ranges as low as 6.8 but visually, the pH appeared to be far lower. So I tested distilled white vinegar, diluted at 5%, which has a pH of 2.4 and surprisingly, it didn’t look that far off from my runoff test. However, with a little quick search of phenol red, the pH indicator that came with my kit, I learned it only reads and displays a gradient if pH is in the range of 6.8 to 8.2 and shows bright yellow below the range and fuchsia above the range (which I should have known since that is the range on the tester). So all I know is that after pouring 7.5ish pH water through my soil, the runoff was lower than 6.8. At this point figuring out soil pH seems like a guessing game, but to have a drop from 7.5 to below 6.8 means the soil has to be significantly acidic. Indicating my soil pH to be lower than 6.8, which is about what I am aiming for, I went to the farm supply again and bought some calcium carbonate. As an amendment, it will raise the pH of the soil without adding magnesium (since I had already added some). I tilled up the topsoil with my hands and mixed around the calcium carbonate. Unfortunately, because of root growth I couldn’t get deeper than an inch or two so the carbonate has not penetrated deep into the soil. I watered with 2 gallons of pure water and called it a night. This is where I am at with this whole thing: I think I have a phosphorous deficiency because although the plant naturally has slight purple stems from genetics, they are VERY red/purple stems, in addition to the browning of the leaves in this specific manner. I am not sure if I have a magnesium or zinc deficiency however, maybe even both. The ridging leads me to believe it could be zinc. The interveinal chlorosis can be a symptom of both zinc and magnesium, and the plant is exhibiting multiple other magnesium deficiency symptoms (old leaves dropping off at the bottom, twisted growth, leaves curling, and a slight droop/wilt to the overall plant). So with this information, I am assuming it is a low soil pH locking out multiple nutrients. I am hoping the calcium carbonate brings the pH up, but I think that is a slow process. I might look into a quicker solution as it is getting worse by the day, but am worried with the now added carbonate, if I add more pH raising substances, it will surge and then I will have a high pH and the same problem.


Reflecting, I realize one of my largest mistakes was reacting to each set of symptoms with a different solution (aka nutrient). What could have helped me sooner would have been stepping back, considering why my plant was exhibiting signs of 3 different nutrient deficiencies, and finding a solution to nutrient absorption of the plant, and not how much of each nutrient is in the soil.


So what do you think my next move should be?


A few things I forgot: I have poured a few gallons of clean water through it, but I don’t know if I consider it a real “flush"; I think I should flush more. I JUST switched to flowering last night. I had to or things would have been disastrous, space-wise. Also, I think this issue has either stunted my plant or just slowed growing extremely. The leaves in general feel dry even though the humidity is fine, and the yellowing seems really concentrated on the vegetation exposed to light (undergrowth is still really green aside from the select leaves that wilt and die).

IMG_20160225_173339.jpg
 

AZPsyclops

Well-Known Member
Plants can go through anything from insects to water and room temp changes.
The best way to get answers is to show us pictures.
 

GR0WL0

Well-Known Member
Plants can go through anything from insects to water and room temp changes.
The best way to get answers is to show us pictures.
That is a picture of the progression of leaves. Are you asking for a picture of the whole plant? My temps and humidity are good, I have a very small fungus gnat population but I don't think that is impacting it.
 

GR0WL0

Well-Known Member
Here is an image of the whole plant: http://imgur.com/bN6Q8iX

I am aware gnats and flys impact a plant, but I just don't see how a population so minor would lead to these issues, especially when the plant is exhibiting quite telling signs of deficiencies.
 

GR0WL0

Well-Known Member
Once those nice shades are dead in veg; bad news.
So, I looked up what fungus gnat damage looks like and I can now completely see where you guys are coming from. It looks quite similar to the leaf damage I have. What I don't understand is that I had a MUCH larger population a month or more ago and noticed absolutely no damage. In fact it was the healthiest the plant has been. Also, what do you mean once the shades are gone bad new? I realize switching to flower was not the best decision but I HAD to. With the ScrOG screen on, you could see that it would over fill.
 

GR0WL0

Well-Known Member
Could be over watering.
Do you use a digital moisture probe? Have you taken a peek at the roots?
Soil could be too packed, etc
It could be overwatering I suppose but I usually wait until the soil is fairly dry to water. I do not have a moisture probe, but I usually stick my finger in the soil regularly to keep an eye on how dry it is getting. I'm not sure how to take a peek at the roots, but I would be glad to if you elaborate. My soil seemingly has good drainage but I suppose it could be too packed. I have grown with this same soil though and each time haven't packed it down differently so if it worked for other plants with this method I'm not sure if it is the variable affecting plant health.
 

AZPsyclops

Well-Known Member
The plant grows those nice fat shades for a reason.
If your leaves cant perform photosynthesis your plant will not produce.
Leaf Damage during veg. or flower can and usually will shock your plant.
The more damage to your plant in general will result in a very week harvest.
 

AZPsyclops

Well-Known Member
If your plant is still in early flower,(first week or two), use insecticide. they make a few including Doktor Doom.
 

Chunky Stool

Well-Known Member
Yeah man, honestly it sounds like a root problem. I've got a Durban poison that's recovering from a mite infestation & will post pics shortly. I'm going to pop I out of the bucket & have a peek at her roots.
 
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