Withering leaves, but it's not N def! Coco, Super Silver, 4 weeks into flower.

L

LoveTheMaryJane

New Member
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new here.. so maybe these will show as pics, rather than links, when I post this query..

So. Here's the story.

This grow is Super Silver, and OG Kush. Both strains are affected, with the Super Silver being the worst.

Growing in Coco, with perlite,

Using Canna A & B, plus Cannazym, Rhyzotonic, PK13/14, Boost, Superthrive. (as required)

using the Light schedule, at 80% strength.

4 plants, 600 Watt HPS, exhaust and intake fans, de-humidifier keeps it in the lower 40's, and temp is 25-28 in the day, and lower when lights are off, depending on the ambient temp outside the tent. Tent is 1.5 x 1.5mDR.

There are also two fans alternating, large, to move the air around the plant leaves.

Grown this way many several times before, without encountering this problem. I've had leaf curl before... which I don't have this time.. (I think that was due to overferts)

The only difference I can think of is that I'm not using virgin coco. Using stuff from the last grow, which I washed, rinsed and dried. And, I'm also using a bit more magnesium. (3gm/10 litres - using very soft water)

Over the past three weeks, I've lost a lot of the lower leaves - now - this is normal.. but the way these leaves are wasting is new, and not N def. Ok, the lower leaves are looking a little pale, but the upper part of the plants are fine.. flowers looking good, leaves a healthy green.

The withering always starts with the lowest leaf on the node.. and then works its way up the plant...it's confined to the lower sections of the plants at the moment - flowers and upper leaves all look just dandy.

In the worst plant, the leaves are limp, and look like they need water... but they don't.

They suck it all up ok..

i water every four or five days or so.. these are in 20 litre airpots, 20% perlite, the rest coco.

Works out at ph 5.7/5.9, and ec of 1.6 max. Water is temperature adjusted to prevent any shock.

Just checked the runoff (yes - I know - I've been advised that the runoff values mean nothing, but I give you them here for completeness) is around 2.00 ec. Now.. that just doesn't seem right to me.

So.. looking for assistance please..

To conclude... growing conditions are virtually the same, apart from:

Using re-cycled coco (second time around - second use of this batch)

Using a lower strength of A & B.

Using slightly more Magnesium.

To my way of thinking - none of these changes on their own, would cause this, unless the coco wasn't properly washed after the first use. Residual ferts would be my guess. Perhaps I didn't give it enough of a wash?

What you think?

Tks Prealbo
 
Well..

I don't feel so useless now... 249 views, and not one reply..

Don't get me wrong - I'm not ungrateful - the information on this site is great - just can't think why so many of you have looked - and not responded.

I think I've given enough information... so I still wonder what is causing the problem?

Regards

Prealbo
 
my friend the reason you have had so many views and no responses is plain and simply because it appears to be a difficult one.

on the surface it appears your doing everything right.

now im not all that experienced with ec but if the output ec is greater than the input ec then im suspecting a serious salt or nute build up.

the only advice i can offer right now is to make a large volume of weak food and flush the hell out of it. also you may want to consider things like h202 to kill some nasties and oxygenate the root zone and also enzymes that break down dead organic matter in the soil e.t.c
 
I can't claim to know what this is but my first instinct was some sort of micro organism in the medium. I would definitely give it some H2O2 in moderation. Does the coco have a funky smell? Like a stinky aquarium or something sorta like it?
 
Gigabane... thanks for the attention, and advice. When i noticed this first.. I measured the runoff, and it was even higher.. about 2.2..at that point, I flushed till the runoff was way down, around 400 ppm - which is still quite high, but a huge improvement.

It would seem that this is a re-occurrence. Perhaps I need to allow more runoff when watering... Usually, I only water/feed till I get about 5% runoff.. so this could well cause a buildup of salts. Can't think what else would be causing it - other than maybe the residual salts in the Coco in the first place, keeping in mind this is the second or third time around for this Coco.

Since I flushed last week, the problem has slowed down - partly due to less foliage due to the previous damage caused - and partly, I hope, due to the flushing.

Ok.

Next grow starts with fresh coco and perlite. And I may even cut back more on the frets.

The figures that Canna give on their chart for recommended quantities and EC values, are based on 1,000 watts of light.

I'm using 600 watts, so, really, the quantities/dosage should be reduced by 40%.

Makes sense to me. Reduce the light by 40%, you should reduce the feed quantity by the same.

Otherwise, the plant is getting a feed too rich for the available light.

Seems to me that the manufacturers always recommend a higher dosage than is necessary.

It's easy enough to try out - I've already been working on Canna figures less 20%.. so next grow.. will be Canna numbers less 40%.

Easy enough to rectify if there's not enough N.

Elious - I'll get some H202 , and give it a try. It's something I've never used,because I didn't know HOW or WHY it was used..but I've resolved that now.. As you ask, the Coco smells ok.

Prealbo
 
Coco retains salts much more than any other medium from the research ive read.
If this is your 3rd run using the same medium.....well, its pretty obvious whats goin on here.
You may need a flushing/wetting agent such as Fox Farms "sledgehammer" to release the salts from the coco that regular water flushing isnt removing.
I have no expierence with coco......just what I have read. Good luck!
 
I know you said its not water. But it sounds a lot to me like it is under watering.

5 days between waterings for perlite and coco with a 40% humidity sounds really low. Especially that you said it starts with the lower leaves and works up. You pots are only 20 liters too.

I was not super clear on this from your original post but, if when you water everything for the most part is good, but then after a few days or day the bottom leaves go bad it is infact a watering prob. Plants kill off the bottom leaves first when things get too dry.
 
I think Jimmy may be on to something here...........I reviewed your original post again and found a couple of clues.
1) You are using 2 large fans
2) You are using air-pots
3) You are watering every 4-5 days
4) You are watering until you get 5% run-off

2 large fans are gonna dry your medium pretty quick.........especially seeing that you are using air-pots which dry out much faster than a regular pot.
Watering every 4-5 days sounds like its nowhere near often enough.
It doesnt sound like you are watering enough when you do water.
I use a 7 gal air pot and have to water every other day with a very heavy watering (but im in soil/perlite)
Sounds to me like your medium is drying out and starving your gals......
 
Thanks again for your replies.

It's not underwatering. I do "the lift". It's not exactly scientific - but it's how I always estimate. The leaves do indeed LOOK as if they need water - but I can assure you that they don't.

Dirty Danny.. pretty sure you're right on the money about the need to flush. Canna have recently published some good, if a little complex info on EC, salt buildup, and plant needs.

It's only affected two of the plants seriously - the of the other two, one is ok, and the other is showing a little damage.

2 hours later....

Ok. Checked the runoff on the Super Silver, the one affected the most, and it was 2.4

Now, I've had a discussion before, about runoff in Coco, and it's been said that it's no indication of the condition of the coco.

Perhaps not. But I'd say that 2.4 is WAY too high.

So, they've all been flushed down to around 200-300 ppm, and then watered with the appropriate nutrient mix.

I'll keep you informed as to their progress.

The fans, although physically large, are on the minimum setting, and also on timers - 15 mins on, 15 mins off, in rotation. One on, the other one off.

Prealbo
 
Theyre now into week six of flower. The shots shown are of the lower leaves, with smaller flowers, if any. The main blooms are ok at the moment - but I noticed that the dehumidifier had been producing less than it has been. Maybe that's the case at this stage, altho I can;t say I've noticed it before.

I believe that the salt residues were the problem.

Time will tell.

I seem to recall that Drip Clean added to the feed prevents buildup of salts - would that be correct?

YOu want to see a pic of the colas?

Prealbo
 
The more info the better always, Prealbo.

That is really weird that area is already in 6 weeks even though its the bottom parts of the plant. I have seen the underside of plants have more buds in week 1. Whatever this is, its certainly taking its toll.
 
Hello my friend your problem is not watering every day you should never let coco dry you get salt build up also fresh water in the medium brings in fresh oxygen. when I'm in full flower I water up to 5 times lights on .coco is hydro. water to 20% runoff with an ec of about 1.6 and after a few waterings the runoff will drop and if it dont leer the ec a bit.the sweet spot is when they are the same and reuseing coco is a good thing you build up a microherd of goodies but apparently you should get fresh after about 5 runs .unless your roots smell I wouldn't use h2o2 as it will kill the goodness in the coco.
That's the way I see it anyway
 
Two weeks on, and the situation is now greatly improved. I flushed with ph adjusted water till the runoff was about 300ppm, and then fed with the Canna A&B and the rest - Cannazym, Rhizotone, magnesium at .3gm per Litre - 21 gms in this case, for 70 litres.
Pretty sure it was a salts buildup.
They're back drinking normally again. I measure this by looking at the volume put out by the de-humidifier.

I've started using Dripclean again - don't see how it can do any harm, and most likely is beneficial in preventing, or at least reducing accumulation of salts.

Fatty - when you say you water up to five times when "lights on" - what does that mean? Surely you don't mean you water five times in a 12 hour period?
The water/feed I use is kept aerated with airstones, and is made up at least 24 hours before it's required, so there's no problem with lack of oxygen in the feed/water.

I don't let the coco dry out - but 4-5 days seems about right, given the conditions I'm using.

The coco seems to be ok - not musty - and I forgot to mention, I always use Rootgrow when planting on - it definitely has a positive effect on the roots. It's a micorrhizal fungi, and I'm thinking this would be the "goodness" you talk of when re-using coco.

I think, in future, I'll be using fresh coco for my grows.

The problem, as I see it, when re-using coco - it has to be flushed with ph and magnesium adjusted water, and then dried. Not that easy to do in a covert situation. And, it takes time to lay it out, let the sun at it, rake it over - it's no small task. Given the price of coco, and the time it takes to refresh it - it's not worth it for me.

Thanks all for your input.. you've been a great help.

Prealbo

parrotplant.jpg
parrotplant2.jpg
 
Looking good dude but yes upto 5 times in 12 hours it's not often it goes over 3 but power kush I was on 5 waterings a day I don't use a high ppm/ec never over 1.6 coco will only hold so much water and with added perlite there is loads of air in the roots so if I go in my groom at any point and they look droopy I add another 15 min watering on .the way I see it is coco is a type of hydro and in Dwc roots sit in water all the time with an air stone on so if coco holds 30 % air it don't matter if the coco is wet and the more I can bring fresh nutes in the pot the better if you see what I mean .saying that I wouldn't go above 2 times unless you add more perlite but I will say atleast 1 time a day no matter what
 

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