Heavy yellowing, from 2-4 weeks in flower. Crop threatened, any advice welcome!

[Boylobster]

Greetings and thanks to anyone looking. I've been away from the Farm for a while, and I hate to come back on my knees, but I need help. My current grow was off to a fantastic start, but about 2 weeks into flowering, I noticed a general yellowing sweeping through the plants, worst in the fan leaves, and worse in some plants than others. Now they're just past 4 weeks in flower and the problem continues to worsen. If it goes on like this, the harvest will surely be ruined. Expert (or any) guidance would be really, really appreciated.

I grow in the same system, same clones, same nutes, every single cycle, but this problem is entirely new. I'll outline the variables that have changed in a moment.

The basics of my setup: 4x600W Lumateks, Ushio HPS, UnderCurrent DWC, RO water, House & Garden nutes @ EC ~350, pH 5.6-5.9, Capulator's Beneficials, Air-cooled hoods, CO2 supplementation @ 1000ppm... I think that about covers it.

The Pics: These pics aren't great; I had to borrow a friend's camera, and the contrast between the still-healthy growth and the yellowing leaves isn't as glaring as it should be. I'll take some photos during their night cycle, and hopefully the flash will show just how bad this is:



The last shot probably best illustrates the difference in color between the parts that are still relatively well and the those that are suffering. A couple plants have yellowed almost completely from top to bottom - it's f***ed.

The Details: My last run had a serious problem with falling pH, which I attribute to the accumulation of unwanted microcultures in the system. I've never sterilized heavily, the way I probably should between runs. This led me to Cap's Beneficials, which I'm using for the first time from the start of this run. As I said, everything looked *fantastic* until about 2 weeks into flower. The system was cleaned and sterilized heavily before this run began, also.

So, Cap's Beneficials is a new factor. Also, this is my first real run with air-cooled hoods and CO2 supplementation. These are the only two significant changes I can think of.

The system has been flushed recently, and pH is stable as a rock, riding right around 5.6-5.8 without any need for adjustment. Likewise, feeding has been strong and very consistent - seems like the nutrient rez is about as concentrated as it should be.

SO. General yellowing, starting with the older fan leaves? Nitrogen deficiency or lockout? What the hell is going on? Why now? Why just when I started to flower? How do I salvage this run??? Please help! If I can provide any more photos, info, or details, just ask! Thanks so much for reading!

Cheers,
BL

 

[symbiote420]

Not a hydro guy but I'll try my best to help ya!

What's the temp like in there? Definitely not a nitrogen def., that starts from the bottom of the plant. What size containers are they in too? One thing I've learned about using bennies is, you can easily overdo them and cause big problems within your medium, you need to provide more root space because these additives accelerate root growth .....in essence you actually may have to feed them more than usual if kept in a smaller pot size.

Could also be a severe calcium, magnesium, or potassium deficiency too!

*Also make sure it's not a environmental issue before addressing it as a nute problem, it's easier to fix!
Since they're the same cut, and the yellowing seems focused in the middle of the room looks like a hot spot....the lights may be too close and are bleaching the plants and drying out the leaf edges!

 

[Boylobster]

Hey, thanks for the quick reply! Unfortunately, I'm not sure that many of those suggestions apply to my grow. They're in 8 gallon units, and while the rootmass is significant, it's not choking the tubs. I've used Caps Beneficials less than the once per week he recommends, also.

Running air cooled hoods, so hot spots are actually *less* of an issue than they used to be... and the yellowing *does* go down to the bottom - the oldest fan leaves have gone from yellow to dead, and are already dropping off the worst plants en masse. Good eye noticing the center plant, but as I said, those are crappy pics. One of the plants on the side is perhaps worse off. :(

Also, if it *is* a nute problem, the system's been refreshed recently and water chemistry seems to be optimal.

A reasonable dose of CalMag is in the system, and pH is wonderfully stable. This is exactly how I do all my runs, but what's changed is:

1. Had probable microbe problem previous run
2. Sterilized heavily (and thorough rinse, of course) between that run and this one
3. Running air-cooled hoods with high CO2
4 Cap's Beneficials

To the best of my knowledge, all other factors are identical. AND, they were *perfect* until I got a bit into flower. I apologize if it sounds as though I'm shooting you down; I just want to clarify what's going on as I see it. I'll try to get some better pics up when they go to sleep.

Thanks again!

 

[symbiote420]

No biggie! But sometime has to be causing the lockout! It does resemble a severe potassium def though....especially now that you say the leaves are just falling off the plant.

What are the temps like in there? what type of water you using?

 

[cctt]

I've seen root aphids cause symptoms like that before. How do the roots look?

 

[symbiote420]

I was trying to jog my memories because your symptoms was bringing back deja vue.....it just might be what cctt said bro! I've stopped growing in coco coir as it seems to be the source imho!

 

[Seamaiden]

Double check for root aphids first, especially if you've grown using these lines and methods before. Yellow sticky traps will catch female flyers, and I feel this is often necessary simply to help in the process of elimination.

The bennies can cause a N-, quickly, too, if you haven't been offering enough N through this post-flip stretch. So you can try giving a bit more nitrogen and see if they green up.

Unfortunately, it is also during this period, the first month or so post-flip, where the RAs will really show if they're an issue.

You see, the yellowing doesn't exactly mimic a simple N- to my eyes. If you push any N, go EASY. If they burn from it, start treating for RAs or scrap the grow. This is the time to make a decision on it *if* it's root aphids.

 

[reeldrag]

Seamaiden is spot on root aphids they do cause that issue you are having. hit them with tap water I can show you pics when I was using RO and had the EXACT same thing swiched to tap water problems went away in a week or so that is not N issue more then likely its aphids or you could also be getting some sort of lock out from the RO. RO works but it causes as many problems as it fixes it is very touchy

 

[Boylobster]

Woah, many responses, thank you all so much! The Farm truly is a wonderful place... I'll have more pics and specifics up later today, and specific responses to all the suggestions. 'Till then, thanks!

 

[Boylobster]

Ok, busy day, sorry it took so long. Let me get to you each in turn, and then on to the pics. Actually, first, I'd like to post a couple pics from my other room, which is running the same clone, same system, same nutes, same Cap's Benificials, same air pumps even, just to prove that I'm not a complete amateur. This is more or less what the ailing plants looked like prior to flower, thought less compact because this other room is under 4x1000W - almost double the lighting.

Happy plants: Happy roots:

So...
Symbiote: Water temp is always 70-71F, air temp in the upper 70s with lights on, mid-70s lights off. I use RO water exclusively - the tap sources in my area are not very hydro-friendly. EC 350 right off the bat. :(

cctt, Seamaiden, reeldrag: Hadn't considered root aphids, as I don't think I've ever had them. However, as much as I'd like it to be that easy, I don't think I have an infestation. I've not seen any flyers, and looking at the rootmass of several plants, I can't see anything that moves, or looks like an insect at all. I live at a latitude that freezes the world solid for much of the year, and pests are almost never a problem.

But here, you guys can look for yourselves.

Brownish roots on the center plant, one of the worst affected, but I can't find any bugs:


Looks like some kind of rot to me... notice the explosion of newer, whiter root growth? I've circled it, and arrows point to the severe rot. It's as though the roots have died off or weakened, and the new growth is trying again. Please view these at full resolution, and you'll see what I'm talking about.
Close-up of the rot:

Here's a look at the older fan leaves, underneath the canopy:
...and completely dead:

Yellowing moving up the canopy:


So... that's the state of things. I've been growing in this system for quite a while, and I think my sterilization practices between runs have never been up to par. I strongly suspect that my last run was f'd up because of microbial activity, and I think that may be what's happening now.

Your thoughts, everyone? Please let me know if there are more specific photos or information that would be helpful, and thanks so much again.

BL

 

[Seamaiden]

I'm just not a hydro gal, never done it with terrestrial plants (I am a fish-woman). I wish I could tell you more, but with these hips I can serve as awesome bump.

 

[Boylobster]

Thanks for putting your hips in my service, Seamaiden. ;) I appreciate it. No more advice? Can people see the patches of dark rot on those close-up root shots? It's especially evident on the thicker, tree-like root structures. Surely somebody has experience with the kinds of symptoms?

Do I give up on the benificials and start H202 treatment? A few drops of chlorine, even? Any knowledge is welcome.

Thanks!
BL

 

[th3b12ain]

I have experienced the exact same problem and my question would be how old is your base? The h&g a&b?

 

[Boylobster]

Hm... interesting question. Fairly old when I started the run. Maybe a year? 16 months? Hard to say. I ran out within the last two weeks or so and had to restock, sooo... they were using the older stuff from veg through week 3 or so of flower.

But! They were great until I started flowering, and the other, happier garden was fed using the same nutes.

Whatcha' thinking?

 

[GR33NL3AF]

I've got the same problem but I am in soil...Added N last night and seemed to make it worse :(

 

[Seamaiden]

I've got the same problem but I am in soil...Added N last night and seemed to make it worse :(

I really, truly hate to say this, but that's one of the signs of root aphids. I'm sorry to be the one to say it.

 

[th3b12ain]

I fixed my problem by replacing my base I was running h&g coco a&b which was a year old I was getting salt build up around the rim off my bottles. My problem was the base when bad and my buddy had the same problem once I replaced my base and flushed my plants they when back to normal.

 

[GR33NL3AF]

I really, truly hate to say this, but that's one of the signs of root aphids. I'm sorry to be the one to say it.

lol, dont sweat it Maiden. I just got done battling aphids in my roots organics beds at another location. What I dont understand is that I had a MASSIVE infestation at my other location and my plants never looked as severe as these do. Ill be posting some pics and info on my own post later this evening

 

[DixinCider]

looks like you could be bleeching your plants, how close are your hoods to your plants?

 

[Boylobster]

th3b12ain: Thanks for the suggestion! Again, I wish it were something so simple... but my other spot used the exact same nutes (I had to lug 'em from place to place : P), and has nothing but pearly white roots. So... I'm not sure that can be the primary factor.

DixinCider: Well... the hoods are air-cooled, and not very hot under the glass. Plus, the symptoms are worst on the oldest fan leaves, well underneath the canopy. Take a look at the pics, maybe? It's a thought, though, thanks!

To anyone else who might roll through, I'm almost entirely certain that this is a microbe/root health issue. Look at the close-up shots of the root mass - browning and die-off on some of the thickest structures.