man, i need some serious help

alright gang, into the 5th week of flower now and havin some issues( lets just say the majority of the grow has been problematic) prob my own fault for tryin dwc on my first ever attempt.

setup.
1200w(2x600) air cooled lights and seperate fan
intake and extract fan with more than adequate air exchange for room size
6 pot(18l) iws DWC system, ( shared 100l rez)
eco tecnics fan contoller maitaining temps of 25-30c with lights on
canna aqua nutes a+b, rhizo, zym etc (no boost)
Using A 50/50 MIX of R/O WATER and Tap, recommened e.c of nutrient according to cannas feeding schedule is 1.4 for the stage im at (ec of ro and tap mix is 0.3) my mix is at 1.7 ec1.4 for nutes +0.3 water and ph at 5.8-6. rez temps are kept between 20-22c
3 different strains aswell ( which i now know was a big mistake, all 3 have different sweet spots for nutes and im using a shared rez but nothing i can do about that now)

plants are 6-8 inch from glass and iv thinkin heat stress is my prob but i can keep the back of my hand at about 3" from glass all day long( it is a sealed system with cold air from outside sucking over the lamps)

my plants are looking unwell, mainly on the top 1/4 of the plants, heres a list of whats goin on:-

leaves are conoeing inwards and feeling pretty dry(not quite crispy)
yellowing on some fan leaves but maily sugar ones
rust spots on most leaves( not sure if this is nute burn of a cal/mag def) i use half tap water in my mix to get calcium etc

i dont know where to start
what sort of ec am i looking for in this setup
should i be adding anymore nutes other than the ones iv stated, do canna not have everything needed already in their mixes?
is the back of hand rule with heat from lamps enough to go by?

any help would be great and will get pics up later if needed

cheers

pics 12345char

yellowing is hard see from the light but damn, this looks even worse on pics than with naked eye! i need to sort this soon, from the pics u think they can recover and still yield well? another 3 weeks to go on saturday :-/ cheers for any help

looks like nutrient burn or cal/mag issues then again it could be something with the PH but your PH levels sound good. I would do a res change and add cal mag at 5ml / per gallon see if things change in the next 48 hours.

cheeers for reply mate, my p.h sits at 5.8 comfotably and rises to 6.0 reckon i should do the change and feed lighter aswell ? i have no cal mag so will have to wait till tomorro till i can try, u think these will die or can they recover from a bad case like this, does nute burn caus leaves to curl and go crispy(ish)? i swear the canna feeding chart is whats caused all my problems, i had these exact same symptoms in veg minus the yellowing and curl and couldnt sort it out , just sort of went on its own after res changes etc, i was under the impression it was wind burn beacuse i had fans blowing directly on the canopy(fans are now moved) and a few week down the line its back

mattyg151 said:

cheeers for reply mate, my p.h sits at 5.8 comfotably and rises to 6.0 reckon i should do the change and feed lighter aswell ? i have no cal mag so will have to wait till tomorro till i can try, u think these will die or can they recover from a bad case like this, does nute burn caus leaves to curl and go crispy(ish)? i swear the canna feeding chart is whats caused all my problems, i had these exact same symptoms in veg minus the yellowing and curl and couldnt sort it out , just sort of went on its own after res changes etc, i was under the impression it was wind burn beacuse i had fans blowing directly on the canopy(fans are now moved) and a few week down the line its back

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Yeah over fertilization will make your leaves do what we call in the states " Eagle Claw" most of the time the leaves will curl down. Ph issues and heat issues will make your leaves get crispy on the ends and curl up. Those leaves wont recover at all so I would probably pluck them add some cal/mag and monitor and keep the water levels low. 5.8 drifting to 6.0 is good how close is your light to the top of your plants?

yeah...the spaces in between the veins being yellow and dead usually means a magnesium deficiency fixed with calmag, but alot of that looks like that plant it getting too hot...

The plant isn't getting too hot. It's toxic salt buildup. Do you routinely flush your system in clean water?

As an yeild-increasing experiment, I overnuted my Diablo OG plants. Look at the leaves. Familiar? I attribute this to salt buildup. Even though I was flushing with water weekly between water changes, the nute concentration was so high throughout the plant's life, buildup was unavoidable.



I sure increased yield. But at what cost?




OG's don't usually donkey-dick like this, btw. I artificially forced it.

wow, cheers guys, i have had to super crop my plants a bit to get the canopy even(vegged too long and outgrew my space!, lights are about 6-8" away but the cooling is good so i dont think its heat stress,lordjin, you are the man, iv never flushed with water beacause i use ro and filling a 100l tank takes ages , can i just flush with tap water? i however then encounter another problem if i can use tap water, mines comin outta the tap at like 10c so flushing will shock! any suggestions on this? surely havin this salt buildup (over ferting) will damage yield , not increase it?? im due a rez change tomorrow, so what shall i do? just mix a weaker soloution than what i have been and add cal mag? to keep ec low, shall i add cal mag and lower my a+b nutes to account for it ie if im feeding to my canna chart then add cal mag at dosage stated bottle on my ec flies up to over 2.0!

A thirty minute clean water purge of your system every week won't shock the plants.

The thing is, with overnuting, unlike lockout, the plant continues to grow. It continues to grow beyond its capacity in fact. This increased overall weight of yield, but decreased the overall quality of the final bud. Not worth it.

Nute mildly and your plants grow smaller but much healthier and happier, so you end up with better bud.

I'd say purge your entire system with plain water (tap water if you have to, but try to set aside some time to gather the required RO). Let them run on this plain water for at least an hour before re-introducing your weaker nute. Your plants are younger than the Diablos in my example pictures, so you still may have time to clear some of that buildup out.

really appreciate your help mate, thanks, ill have to use tap water , really hard tho 0.6 ec , will this be ok? could i flush the plants for a day? ie start before i go to work to then do a rez change when i get home or is 8+ hours too long on just plain water for dwc? have you got any preffered feeding/nutes you use? or is canna just as good as the rest if used properly?
just one last thing im in week 5 of flower and adding pk 13/14 as of tomorrow, what sort of total e.c (additives and nutes) should i be looking for in this stage?

Well that's pretty rough tap. If it's all you can manage, tho, it's better than nothing.

I wouldn't let them flush for more than a few hours. An entire day means the plant will try to grow without nute.

I'm sure Canna is an effective line of products (when used properly). I like the fact that it's called Canna, much like the AN Sensi I use is called Sensi. I can't speak directly for Canna, but I will say that AN Sensi doesn't leave the 'thumbprint' on your bud's smell and taste the way General Hydro products do. With AN Sensi, all you get is the smell and taste of the weed you grew. With GH, you smell and taste the GH as well as your bud.

Hey mattyg151, I took out the effects of your light to bring out the problem a little more. Hope you don't mind.

no thats fine mate, cheers gonna do a flush, res change tomorrow with a weaker mix and cal mag, just found out some bad news, my grasslin timer has wedged on!!, not sure for how long, maybe just today im now 6 hours over my usual schedule or could have been on constant for last week! so things have gone from bad to worse, im using a contactor for lights but plugged a supplementary 250w cfl into aswell, i thought it would be fine with such a small load!! are my babies guaranteed to be hermie now !! gutted cant wait to get this 1st outta way now, hopefully 10 fold better next time

Those some super nice colas my brother!

Ive had similar problems with my plants in a single res. Too be honest its probably a mixture of toxic salt build ups (as already suggested) and possible a low-Dissolved Oxygen level in the water. I only ran 1 air stone for 2 flowering plants. LOL they hated me. My 2nd grow has much more air stone... doing much better and I dont have the problems with leaves as I had before. So I suggest an air pump/stone upgrade if you're plants dont perk up with some cal-mag and lower PPMs w/flush(es).

Vumar said:

Ive had similar problems with my plants in a single res. Too be honest its probably a mixture of toxic salt build ups (as already suggested) and possible a low-Dissolved Oxygen level in the water. I only ran 1 air stone for 2 flowering plants. LOL they hated me. My 2nd grow has much more air stone... doing much better and I dont have the problems with leaves as I had before. So I suggest an air pump/stone upgrade if you're plants dont perk up with some cal-mag and lower PPMs w/flush(es).

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That's a thought. Good lookin' out. Based on your assessment, I would say that by process of elimination it was salt buildup in my case because I bomb my res with DO.

edit:
But then again, the lack of dissolved oxy would lead to the buildup. In my case then, it was an amount of nutrient so overwhelming, even ridiculous DO wasn't enough to prevent buildup. And that's the way it really went down. That's about right I think.

Lordjin; Ive got a 70 litre/minute commercial air pump with 8 outputs. How many 5" bubble discs should I get per 5gal bucket? I figured x2 discs, because I thought x1 might not reach the desired DO level.

Vumar said:

Lordjin; Ive got a 70 litre/minute commercial air pump with 8 outputs. How many 5" bubble discs should I get per 5gal bucket? I figured x2 discs, because I thought x1 might not reach the desired DO level.

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Wow, I like the way you think. 1 disc per bucket would be fine. 2 would be super. My kind of hyper-growing. Rep, rep.