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Need help to ID problem


AJA

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Symptom only started since last night, but found the very beginning of either tox. problem or def. problem.  One of my troubles is not being able to tell the difference

between toxicity and deficiency

Its early stages, though it is on a few more leaves than i've shown here, but not everywhere on the plant right now.

Feeding Mega C 1 part to EC 1.2 total - (base EC 0.6) , and pH 5.9.   13.6 Litre fabric pot on drainer

1 feed per day  - 1 litre run off. Runoff pH 6 and  EC 1.9 ,   so runoff EC has jumped.   Havent fed them today yet as gonna wait till i know whats going on.



Advice welcome cool.png
 

 

large_tox.jpg.a404ceef143c55be3299592d2034beab.jpg

Edited by AJA
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What are your temps?

Could you post a pic of the plant?

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Temps 79 F   humid. 55%

 

I'm also seeing some same on new growths .   If you need a better pic, i'll sort one

 

large.toxdef.jpg.9455d24f7b069738865a7a94e7c321da.jpg

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2 hours ago, AJA said:

Feeding Mega C 1 part to EC 1.2 total - (base EC 0.6) , and pH 5.9.   13.6 Litre fabric pot on drainer

1 feed per day  - 1 litre run off. Runoff pH 6 and  EC 1.9 ,   so runoff EC has jumped.   Havent fed them today yet as gonna wait till i know whats going on.

 

we need more info like lights on/off RH and temps to diagnose properly. 

 

The jump in EC would suggest that there is some level of dry back going on - this would effect transpiration which will effect calcium uptake (top image) 

 

However, a single part feed at 1.2 EC in base 0.6 EC isn't alot of food either, you could be underdoing it. I did look it up online, its a complete feed, but in your hard water it may cause imbalances due to there being too much calcium and not enough magnesium to facilitate uptake of both Ca and K between the feed and your tap water - but until we get more information this is just speculation.

 

e2a or it could be both issues, which would explain both the high run off EC (too much dry back/hot temps/low RH) and them also looking starving (not enough feed/unbalanced nutrient profile) 

Edited by GSZZ
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With the runoff EC being so high,

I’d suggest adding another fertigation event per day.

 

But I see @GSZZ typing so I’d probably take his advice 👍

 

 

Do you have a temperature sensor in the pot?

 

Atb

 

 

 

☯️

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Posted (edited)

Lights 24/0   Humidity  55%  Temps  79F

 

I agree EC 0.6 feed to base EC 0.6  is not a lot of feed, but i'm going by the info  on MegaCrop bag of 1.2 for veg.  pH is 7.5 from tap, and i ph down to 5.9 after mixing nutes

 

I dont have a probe in the Coco.   Its Pro 7 Jiffy  buffered  70/30. Photo with lights off but dark room means flash enabled

 

large.toxdefplant.jpg.c733b2b91e80b2d74352a05ac4e67853.jpg

Edited by AJA
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Posted (edited)

42 inches from plant tips.  LED is on 25% ... any lower and the temps rise

 

LED is Omega Black 720 and  extraction is AC Infinity Cloudline 6

 

2 x 5 inch Elzo tent fans

Edited by AJA
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4 hours ago, AJA said:

Lights 24/0   Humidity  55%  Temps  79F

 

Give them some dark ya lunatic.

 

e2a - some might disagree with me, but its too cold - that 79f (26c) should be your lights off, 86F (30c) lights on.

Edited by GSZZ
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They're autos, so i dont bother with a light regime.  Would you still give autos dark time ?

 

86 / 30 is right at  the limit for me, but i'll give it a shot.  I only need to up the Omega to 50%  , as that gives me around 86/30

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42 minutes ago, AJA said:

They're autos, so i dont bother with a light regime.  Would you still give autos dark time ?

 

Based on a few factors, a cannabis plant can only photosynthesize so much light before it completely stops photosynthesizing and just sits there getting battered by light.

 

Autos dont need a dark period to flower but they're still subject to the same mechanisms of photosynthesis that other cannabis plants are (AFAIK) so can only maximise photosynthesis to the minimum factor (usually co2) . Back in't day when people were using legacy lighting tech like low wattage HPS and CFL, the amount of light your plant could use that they were putting out was quite low compared to todays standards, which meant growers didn't have to give their autos a dark period because there was enough co2 in the air, and such little light. The same can be said for photoperiod plants in veg on 24/0, but I'll come back to this.

 

Thats not the case with LEDs as they put out quite a lot of light, comparably. If you can't turn the light down anymore, and increasing co2 isn't an option, your only option is to give them some dark to lower the amount of light they get per day (DLI - Daily Light Integral)

 

42 minutes ago, AJA said:

86 / 30 is right at  the limit for me, but i'll give it a shot.  I only need to up the Omega to 50%  , as that gives me around 86/30

 

Well bare in mind if you're going to increase light to increase the room temps, then you're probably going to have to give them even more dark.

 

Heat the room up with a heater - theres only a 180w difference between 25% and 50% on that light of yours - get a similar wattage tube heater its job is just to get warm, so it'll do it better, more efficient, and ultimately cheaper than turning the light up would, what with heat just being a byproduct.

 

 

I had a similar problem myself recently, when I replaced my old T5 propagation lights for LED strip lights. Despite being less than half the wattage of the T5s, they put out more than double the light - I pig headedly just straight replaced them, turned the thermostat up and thought I'd be ok but a week later I was scratching my head at loads of yellow plants. It was only at that point I put the light meter in there and realised what the issue was, and because the prop lights couldn't (or rather, didn't come with a dimmer) be dimmed the only option was to reduce the light hours from 24/0 to 20/4 - less than a week later everything was back to normal.

 

 

Edited by GSZZ
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Great info GS ...  i shall make some amendments based on your advice.

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Posted (edited)

Since i already had a tube heater in the tent, but not switched on, i now have this on a  digi timer , as is the Omega too.

 

I'm giving the girls 4 hours of dark from tonight ......  lights off from 10 pm to 2am, heater on 9.55pm off  2.05 am

Edited by AJA
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Awesome - the next few waterings, make sure you get a good plenty run off from them also. Come back in a week and show us how they look bud :)

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Help appreciated GS

Indeed m8, i always  feed to runoff.  Getting 1 feed/water per day as i speak.

 

Back in a week  😎

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