New Grower Is this Calcium deficiency or potassium?

[jabben24]

Hi everyone on my first grow running 6 seeds from fastbuds in Coco coir along with. Each plant is in a 5 gallon pot in a 4x4 grow tent. I have two 450 watt LEDs by platinum LED.

I'm on day 35 and in this fifth week I noticed that my tallest and best growing plant, a tangie'matic has been showing some small brown spots on its leaves. It has been growing wildly and it doesn't appear to be stunted in anyway. At first I thought Calcium but I checked the PH of my Coco and it was at 6.3, and I've been feeding extra cal-mag. The problem seems to slowly be speeading. I read that taller plants in flower are prone to potassium deficiency, is that what I'm seeing?

Is this anything I should worry about or should I just keep pressing on? I have another tangie in the tent but it's not showing the same spots. This is the only plant in the tent that's effected and everything else seems to be going great.

Hope you guys can help!!

 

[Mañ'O'Green]

@jabben24 diagnostic picture need to be taken in "Day Light" 5000K or flash with the grow lights off. I don't think it is too bad yet but we need more information to try to nip this in the bud (pun intended).

Please fill in this form: (copy and paste part is below, this first one tell what specifically to include)

-Problem: (brief description)
-Medium/grow method: soil; soilless-- coco, or peat based like Promix, etc. (please provide the actual product name); DWC, NFT, etc.
-Feed and supplements used: include brand, dosage/strength, frequency of feeding and watering (alone); method-- by hand, drippers, rercirc' or drain-to-waste,... N-P-K #'s too if you can!
-Water source: RO/DI; tap- dechlorinated-?..... EC or TDS reading; pH (don't bother with this on RO/DI, do bother with TDS/EC though to confirm it's working well enough)
-Strain and age
-Climate: night and day ambient T and RH%; res' temperatures; any extremes in T/RH% exposure
- Light used: HID, LED, COB, combo of,... wattage; light cycle hours (20/4, 18/6 , etc.); distance to tops....
-Additional info: PH in the root zone. How long have the plants been affected?...How fast did symptoms appear?... Anything else you think might be relevant..

--Pictures including WHOLE PLANT PICS, and troubled leaves.. use normal light or flash as other light sources ruin color rendering, critical for diagnostics!

✂ - - - - - - - - - - -
(copy and paste)-->

Problem:

Medium/grow method:

Feed: and supplements used:

water source:

Strain/age:

light used:

Climate:

Additional info:

 

[jabben24]

Problem: brown spots showing up on some leaves for about a week is when I first noticed. Symptoms seem to progress slowly.

Medium/grow method: Coco perlite 80/20 from Mother Earth. It has been pH buffered. I am hand watering/feeding once per day In 5 gallon smart pots. The affected plant is the largest and is getting 3 liters per day as of today. I dont always get runoff but I would say there is generally a little water in the pan.

Feed: and supplements used: AN Sensi Bloom A+B 2ml/L each, Big Bud 2ml/L, Bud candy 1 ml/L, CalMag Plus 3ml/L, voodoo juice 2ml/L

water source: RO water. TDS 1100 PPM. PH 6.0-6.1

Strain/age: tangie'matic from fast buds 5 weeks old.

light used: 2 platinum led 450 watt. 20/4 cycle sitting 18 inches from the plant with Bloom and veg switches on.

Climate: 78-82 degrees day time. Reaches a low of about 72 degrees at night. RH 45%.

Additional info: I will post some proper diagnostic pictures tomorrow morning. I don't have a pH probe for my Coco so I tested its pH by mixing it with some RO water, 1 part sample of my medium and 2 parts water. I mixed it and waited 10 minutes before testing the pH. It read 6.2. After an hour it read 6.3. My initial thought was Calcium deficiency but other than the spots themselves nothing else would indicate that. Again, the plant seems healthy and is growing vigorously, about 2-3 inches per day on average the last week.

 

[Mañ'O'Green]

You should aim for 10% - 15% run-off every day.

This does not make sense "water source: RO water. TDS 1100 PPM. PH 6.0-6.1" RO should be near zero TDS?

PH is probably ok.

 

[jabben24]

You should aim for 10% - 15% run-off every day.

This does not make sense "water source: RO water. TDS 1100 PPM. PH 6.0-6.1" RO should be near zero TDS?

PH is probably ok.

Sorry about that I misunderstood. I meant that after I mix my nutes up TDS reads 1100 ppm. My RO water is 0ppm.

 

[Mañ'O'Green]

My gut says 1100 PPM and no run-off = salt build up which is also most likely out of balance I would recommend a mini-flush with nutes at 30% strength, to 30% to 40% run-off. If you are running Mykos or other bennies add some.

I just noticed something else "I dont always get runoff but I would say there is generally a little water in the pan." The water in the pan cannot wick back into the coco can it?

 

[jabben24]

My gut says 1100 PPM and no run-off = salt build up which is also most likely out of balance I would recommend a mini-flush with nutes at 30% strength, to 30% to 40% run-off. If you are running Mykos or other bennies add some.

I just noticed something else "I dont always get runoff but I would say there is generally a little water in the pan." The water in the pan cannot wick back into the coco can it?

I'll go ahead and give that a try. It isn't possible that the water in the pan would wick back up because the pot doesn't directly sit in the pan. It's raised over a rack. I forgot to mention that there is a one inch layer of hydroton at the bottom of the pots just to help with drainage if that makes a difference.

Should I run this mini flush for one cycle? Or this full week?

Thanks again for the help MoG this is awesome!

 

[Mañ'O'Green]

I'll go ahead and give that a try. It isn't possible that the water in the pan would wick back up because the pot doesn't directly sit in the pan. It's raised over a rack. I forgot to mention that there is a one inch layer of hydroton at the bottom of the pots just to help with drainage if that makes a difference.

Should I run this mini flush for one cycle? Or this full week?

Thanks again for the help MoG this is awesome!

I would just do it once. If the pots have not dried out the salts rinse fairly easy. Be sure to fertigate to 10% - 15% run-off daily. I still want to see the plants in good light!

 

[jabben24]

I ran the mini-flush and was able to get plenty of runoff. Took some pictures in normal light just after the lights went on.

I just measured her. She’s 34 inches tall on day 36.

 

[Mañ'O'Green]

I ran the mini-flush and was able to get plenty of runoff. Took some pictures in normal light just after the lights went on.

I just measured her. She’s 34 inches tall on day 36.

They do not look bad at all. You should be back on track now. Tag me if it does not stop in a day or two.