Plants In Trouble - Bloom Phase

A couple days ago I noticed yellowing starting to appear on upper leaves of plants. Plant growth has slowed to almost nil at this point. Plants are in week three of bloom and had been growing fine to this point. Three weeks ago I did a complete reservoir change and put in nutes with a proportion for entering bloom phase(GH Gro 2 part- Micro 2 parts - Bloom 2 parts); this gave me a ppm of around 1300 (.5 factor). Since then I had been adding water/nutes to the nute reservoir w/ a 1-2-3 ratio (Gro-Micro-Bloom) and keeping ppm around 1200-1300. I had been having a problem keeping pH level UP and it hovered around 5.3 to 5.4 for 4-5 days before I received GH's pH UP and adjusted pH to 5.8 - 5.9 level.

Yesterday I dumped 75% of the reservoir and replaced with new water and added a vigorous grow concentration of nutes (Gro 3 parts - Micro 2 parts - Bloom 1 part); ppm around 1000 (EC 2.0) and a pH adjusted to 5.8. I thought maybe the plants were suffering from a nitrogen deficiency hence the 3 parts Gro. Since reading up on nute deficiencies it looks like several things could be causing leaf yellowing and some downward curl. Shortage of potassium being one of them. Is there a possibility that the plants were depleting the potassium as they went into full bloom?

attached are two pics of the plants and the yellowing is obvious. The sodium vapor lite did cause some yellowing in the coloration of the pics but the leaves are definitely yellowed.

I am now wondering if I should boost the potassium at this point to see if the plants respond favorably or go the other way and drop the EC down to 1.6 or less.

Dejected by this development,

FSM

If the 1st signs of yellowing was in the new growth then most likely its a micro nute problem. I'm thinking it's mag not potassium. Try adding 5ml/gal cal-mag, if this is the problem they will recover quickly.

Best of luck.

WattSaver said:

If the 1st signs of yellowing was in the new growth then most likely its a micro nute problem. I'm thinking it's mag not potassium. Try adding 5ml/gal cal-mag, if this is the problem they will recover quickly.

Best of luck.

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Wattsaver,

Magnesium is not readily available, according to the nute uptake charts I looked at, when the pH is 5.3 - 5.4 for 3-4 days. I am keeping pH more elevated now and will keep reservoir topped with bloom-oriented nutes.

Been having the same problem with my blueberry every since switching to 12/12......lower older leaves emediately started to yellow..... I thought N just as you did, but when it continued after adding more N to the mix I went with the cal/mag. I plucked the yellowing leaves so I could keep better track & the yellowing seems to have slowed quite a bit...(finishing up week 3)...still some yellowing but nowhere near as rapid as in the begining. Also just upped my nutes, my plant is kinda big & ppm was down around 500/550 range & that was with additives so that may have also been part of my problem.

Hope this helps, good luck to ya

What grow is this of yours? What kind of water are you using? It could be temp related?

What I am thinking since your EC is high, it could be a nute burn?

Also I see you are using the same brand nutes as me.

I am in my first week of flowering myself right now, and my PH I keep at 5.8 and my EC(0.5) is around 800-950.

I use the Lucas Formula and he says you don't need the GH Gro part of it, he says just use 8ml Micro -16ml Bloom per gallon of RO water.

JCave said:

What grow is this of yours? What kind of water are you using? It could be temp related?

What I am thinking since your EC is high, it could be a nute burn?

Also I see you are using the same brand nutes as me.

I am in my first week of flowering myself right now, and my PH I keep at 5.8 and my EC(0.5) is around 800-950.

I use the Lucas Formula and he says you don't need the GH Gro part of it, he says just use 8ml Micro -16ml Bloom per gallon of RO water.

Click to expand...

1st grow so be easy on me. ha.
my water is clean pond/rain water.
I have not had problem running higher concentration (1200-1300 ppm .5 scale) during vegetative. And first two weeks of bloom they grew like crazy! Actually 1200-1300 ppm is what GH recommends on label for aggressive vegetative.
If plants don't turnaround SOON I will dilute nutes to 800-900 and see if that helps.
Right now I think problem was with too low a pH for several days. Dunno. It sucks as everything had been super until now.

What kind of grow is this? Did your roots go to shit?

I suggest dropping the ppm scale, too confusing, just use EC. And if your EC is up at 2.4+, that is really high. I recommend dropping down to 1.9, and you may want to flush them a bit as well.

The first image looks dark yellowing and is going to damage,but yes you can save it using appropriate hydroponic nutrients like PH which is heavy weight bloom booster for plants. I have same problem like you face now and i have used Mills nutrients products to solve this problem,so i refer you to use this product also.. http://www.millsnutrients.co.uk/products.html

Update:

Been about a week now since trying to correct problem w/ plants. The plants seem to have stabilized but the yellow discoloration of the leaves persists. What is odd is that a couple of the plants have normal looking bud/leave color. The grow is in three parallel 6" diameter plastic pipes that are interconnected with crossover lines and they all receive the same nutes and same soak/drain times. If it is a nute deficiency or burn then I would expect to see all plants suffering equally. If it is a root connected ailment I cannot determine that right now since everything is locked in with the scrogg.
EC is set and stable around 1.7; pH is currently 6.2. Here for the past few days the pH has been stable or slightly rising, which is contrary to what it has done (drop) the rest of the grow. Another odd observation is that the nute reservoir, which has about 42 gallons of nutes, has air bubbles that are forming on top the solution. A serpentine air stone is being used to keep the solution moving but these larger than normal bubbles have never been seen before now. ???
During the first two weeks of bloom the plants grew vigorously and to the point that I was having to bend/crimp some growth for lack of head room. They're about 5 to 5 1/2 feet tall but since developing the yellow discoloration new growth has stopped. In a healthy grow do the buds continue to grow all the way to harvest? This is my first grow so the learning curve is whipping my ass right now.

Your EC sounds better, but your ph is now on the high side. You definitely want below 6 for hydro, usually 5.8 or so is the sweet spot. Damage done to leaves doesn't repair, it will either stop as you correct the problem, or will get worse. Look to new growth to see if you've corrected a problem, but it sounds like "the stretch" has stopped if you are past week 4, so there will not be much new growth, just fattening of buds.

About different plants reacting differently, this would be expected if you grew from seed, each plant's genetics are a bit different.

SnaFuu said:

What kind of grow is this? Did your roots go to shit?

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SnaFuu,

I think the roots are the problem. See update.

It has been 12 days since the yellowing problem was first addressed. The plants have not responded to new nutes, less solution concentration, and pH elevation. There are some that still look OK but the majority have yellowing of leaves, primarily on the buds. Unfortunately the plants don't seem to be growing/maturing at this point. Yield will be severely impacted. All that phuckin' work down the drain.

What I did today was look into a spare opening on one of the grow tubes and check out the root system. I believe there is a high likelihood the roots are the source of the yellowing problem. Why? I had been using wood ash filtered through a double cotton cloth to keep the pH up. This worked fine for the first couple months but then the pH got to the point where it would not come up much with the ash and would quickly fall off afterwards. This is when I decided to purchase some pH UP. The root mass is a grey color and limp. It appears to be coated with the residue of the wood ash. This coating probably has a serious impact on the ability of the roots to absorb nutes and oxygen. They grew fine the first two months but the accumulation of residue on the root system over time has reached the point where growth is being inhibited and even damaging the plants.
With the plants "grow-locked" into the scrogg I cannot remove them for cleaning of the root systems. Flushing is not effective as the flow rate is too slow too dislocate the ash residue. Basically I'm screwed.

Does my observation seem reasonable?

Hope you have it sorted but just a couple of things. Not so sure ph should be below 6 in flowering, i run some strains as high as 6.3, but hey i'm a newb. Also I do think you were pushing the limits on your TDS levels and that would explain ph dropping. I have 4 plants in each rez all the same (Kosher) and two of the plants are showing mag def. so I have been foiler feeding epsom salts and it has cleared up. Just saying that same strains will show different issues.

Update:

Attached are pics of the plant root systems. The buildup of wood ash residue is obvious.
pH UP or other chemical adjuster is CORRECT way to keep pH balanced. Live & Learn.

Well at least you got her figured. Yeah my money was on the roots, since ive lost a few grows like this aswell.

Hey look into microbe tea, ever since starting to use it (for other reasons) my ph stays at a stable 5.8 throughout the whole water cycle. The most ill have to tweak it is 12 hrs after a water change and then she's good for the next month!


Good luck on the next one!

It's tough losing a grow, especially so late in the game. Learn from your mistakes and move on....

You got it. It's happened before and it will .... NOT ... happen again.

lol