Cooked leaves - nute prob?

[Al B. Fuct]

Stoney & I were comparing notes the other day and we both noted we've had some batches with badly cooked fan leaves by the end of flowering.

 

 

Week 8, room temp 24-26C, 40-50% RH, Canna Flores nutes @ 1400ppm, pH 5.5-5.8. Lights are 1000W HPS.

 

Bud weight development is ordinary but super dense, rock-hard, crystally buds anyway.

 

All other conds right- what's wrong?

 

Stoney noted he also uses Canna nutes. A bad batch of Canna for both of us? Any other Canna users noted this?

 

Thanks.

[torana2000]

do you change nute every week and flush out bettween changes.

[Tom]

Some of that damage looks like PH to me, I would bump it up to around 6.0. With Canna nutrients you also need to add a little magnesium to your reservoir, I used to add a teaspoon of Epsom salts per 50 litres.

 

[Al B. Fuct]

do you change nute every week and flush out bettween changes.

 

Tanks are dumped and cleaned every 15 days.

 

Some of that damage looks like PH to me, I would bump it up to around 6.0. With Canna nutrients you also need to add a little magnesium to your reservoir, I used to add a teaspoon of Epsom salts per 50 litres.

 

I did have a pH meter go south on me a while back. It was lying, telling me the pH was 5.5 when it was closer to 5.1-5.2. Could be part of it. I've gotten a replacement meter. Wonder if this batch of plants was one of those affected by the bad meter. I thought I caught the meter failure only a week or so after it quit. Might have been dodgy for longer than I thought. I do tend to run pH a bit low (usually 5.3-5.8) because I've been using rockwool floc, which has a bit of limestone dust in it, which causes pH to rise a couple of tenths every few days.

 

I've seen what appears to be Ca deficiency spotting, could also be related to low pH from the meter failure.

 

Tom, I've got some MgSO4 on hand. Will dose the tanks when I mix up new batches tomorrow. Thanks for that.

[loylty gets u nothing]

looks like some yukky bits al

i get that towards the end wen im flushing

i too think me meter is out as i get twisted distorted growth at times

u dont think 1400ppm is too much for week 8??

i usually am tapering off nutes and preping for flush

all the best

bil

[Al B. Fuct]

billo, I COULD flush at the end of 8 wks but when I do, I can't seem to tell any diff between buds from plants that have been flushed and those run on regular strength nutes to the end.

 

Sometimes I can leave plants in for longer than 8 wks; another week or two does make a difference in yield. When it happens that I can leave them to flower a bit longer, if the last tank has been on plain (pH adjusted) water from the beginning of wk 6, they get pretty N deficient by wk 9-10.

 

I've been using 1400ppm as the target figure for Canna nutes for about 7 years. I'm hoping that this is all caused by one lying pH meter.

 

Thanks to everyone for thinking about this one.

[Al B. Fuct]

While I don't think I'll usually need it, I got a bottle of Canna branded Ca supplement liquid. Old stock in ye olde hydroe shoppe, not sold by Canna anymore to my knowledge. Still wasn't cheap at $20 for a litre. No mixing instructions, either!

 

What common calcium containing stuff can be used for a Ca supplement that won't monkey around with the pH too much?

 

In my trial batch of plants in Fytocell, I'm not going to correct pH as I usually do for plants in rockwool. The pH buffers in Canna Flores set the pH right around 5.8 when making up a 1400-1500ppm soln (400ml A & B in 125L) with 7.1 tapwater. Fytocell is said to be "pH 5.5-7.0" on the pkg and won't have any limestone debris in it requiring compensation in the nute soln.

[bufo marinus]

Gday Al, just thinking back through my own fuckups and reading through some stuff I have here.

Looking at those finished flowers I reckon your room conditions are correct.

pH ? don't think so, anywhere from 5 to 6.5 is fine imo

Iron deficiency? I doubt it, I've given my plants a dose of that by adding my nutes too high ph (anywhere over 7.5 no good) when first started using Silica. The leaf did yellow, but only in patches, not evenly, like those plants of yours. Plus a micro nutrient deficiency would show up in the new shoots, not the old leaf.

Nitrogen deficiency? possible, but I would guess more likely Potassium.

Nitrogen would start showing from the bottom leaves up whereas those flowers have all the leaf affected equally and is worse at the leaf tip/margins, easing off closer to the main leaf vein, textbook Potassium def indication.

Not sure what the cause could be other than possibly your guess of a bad batch of nutes? Happy gardening

[Al B. Fuct]

bufo, thanks for that.

 

I have left out a bit of information- forgot to mention that I use Canna's PK13-14 @ 2ml/L for 1 week in wk 3. PK13-14 is a phosphorous & potassium supplement, NPK is 0-13-14 of course.

 

I wonder if I'm shooting myself in the foot by hitting them too hard with the PK. Canna's instructions suggest a range of 1-2ml/L and I'm on the upper end.

 

PK13-14 also tends to raise pH quite a lot- you'd think it'd be the other way around. A 125L tank already mixed with 400ml each Flores A & B to yield 1400ppm, sits at 5.8 right after mixing, 250ml of PK13-14 will raise the pH to 6.2. Takes about 20ml of ye olde pHDown (phosphoric acid) to bring it back to 5.8.

 

I doubt there's a deficiency of anything- I suspect that I'm causing the appearance of a deficiency with an excess of something else I'm chucking in the tanks.

 

Used Tom's suggestion and put 2 TBS Ep salts in each 125L tank when mixing up today.

[Tom]

Used Tom's suggestion and put 2 TBS Ep salts in each 125L tank when mixing up today.

That was teaspoon not tablespoon, 2 tablespoons will be way too much.