HELP! Extreme calmag deficiency and Nute Burn??

[ganjaman21]

Hi guys!
This is my 1st grow ever and I've been struggling with some kind of mobile deficiency this past week.

I'm growing 2 autos (Sticky Beast / Diesel) in soil (DNA/Mills soil with cork) in 14l pots. I'm now on day 48 from seed.

Water goes in at 6.9ph and comes out around 6.1ph.

The sticky beast strain is the sickest: the deficiency started after early flowering on the lower leafs and is moving super fast. It's already affecting some of the top fan leafs. I suspected calmag deficiency and started water feeding calmag for the past 2 waterings (1ml per liter of water), but the problem doesn't stop..

Furthermore, she's clawing a little bit, burnt tips started to appear and I have no clue what to do with her. I doubt is nuteburn because both plants are in this soil for about 30+ days.

I never flushed the medium. what should I do? I don't want to lose one of my girls.

Please see the pictures!

 

[Jimbojohn]

Provide additional information:
Light type? Feeding schedule? Etc...

Purple pictures are useless.

Leaf necrosis looks to be a P symptom - @ 48 days, your P/K needs are ramping.

You want to cross a 5.8-6.2ph threshold to ensure variable nutrient uptake. In at 6.9 and out at 6.1 is limiting nutrient uptake.

PH in at 6.3/6.4, look for a ph out in the 5.5 range and get some P/K in there.

1ml/L of Ca/Ma is likely your upper threshold for any light type giving off that much blue/purple.

 

[ganjaman21]

Provide additional information:
Light type? Feeding schedule? Etc...

Purple pictures are useless.

Leaf necrosis looks to be a P symptom - @ 48 days, your P/K needs are ramping.

You want to cross a 5.8-6.2ph threshold to ensure variable nutrient uptake. In at 6.9 and out at 6.1 is limiting nutrient uptake.

PH in at 6.3/6.4, look for a ph out in the 5.5 range and get some P/K in there.

1ml/L of Ca/Ma is likely your upper threshold for any light type giving off that much blue/purple.

Thanks for the help!

I'm taking new pics in a couple of hours.

I'm using an amazon 300w LED with the veg and bloom switch on 20/4.
As for the feeding schedule, I'm watering them every 2/3 days. Just tap water because this soil has time-released nutrients.

I'm not adjusting ph since the guy from the store said the soil would act as buffer.

Do you think I should switch to the red LED for next the 3 weeks?

 

[davisgirl]

You’ve got more than 3 weeks to go. Put the bloom switch on. 20/4 is pushing it — while you nurse them through I’d run it at 18/6. Your soil is not providing what she needs in bloom. I’d feed a light strength bloom nute, and wait and see what the others say. I’m pretty much a noob but I’ve been hanging around a bit, so weigh that fact when you consider my advice.

 

[ganjaman21]

You’ve got more than 3 weeks to go. Put the bloom switch on. 20/4 is pushing it — while you nurse them through I’d run it at 18/6. Your soil is not providing what she needs in bloom. I’d feed a light strength bloom nute, and wait and see what the others say. I’m pretty much a noob but I’ve been hanging around a bit, so weigh that fact when you consider my advice.

Thank you very much for the feedback!

Tomorrow I'll buy some kind of bloom booster and I'll leave the bloom switch on for the rest of the grow.

One more question: how long does it take for the plant to recover from this kind of deficiencies?

 

[davisgirl]

If we guessed right, the deficiency should stop spreading and she should look better overall pretty quickly. The affected leaves will never recover.

 

[Jimbojohn]

Thanks for the help!

I'm taking new pics in a couple of hours.

I'm using an amazon 300w LED with the veg and bloom switch on 20/4.
As for the feeding schedule, I'm watering them every 2/3 days. Just tap water because this soil has time-released nutrients.

I'm not adjusting ph since the guy from the store said the soil would act as buffer.

Do you think I should switch to the red LED for next the 3 weeks?

What soil type? Be highly skeptical of any time release soils not specifically designed for cannabis cultivation. Even then, most will only take you through 3-4 weeks of growth.

You're soil is buffering, it's why your 6.9 in is down to 6.1 out. Optimum ph range for nutrient uptake is between 5.8-6.2. You need a lower ph in to cross that optimum threshold.

I'm in at 6.3-6.4 and out at 5.5-5.6.

Also, there is no 'recovery' - you're looking to stop symptoms, anything necrotic is gone.

Again, this looks like a typical p/k issue, you need to get a bloom supplement with sufficient potassium and phosphorus to feed through flower.

 

[ganjaman21]

Thank you so much!

Let's see how she reacts. I'll be feeding her on Tuesday with the p/k booster and PH balanced water around 6.3 to 6.4.

Do you have any brand that you recommend?
Should I ph the water before or after adding nutrients?

 

[ganjaman21]

 

[Waira]

looking like P defc. to me as well,... pH of run-off, while not an accurate measure of actual in-pot pH, does indicate that the incoming water is getting acidified when it comes out, quite a bit,... that run-off pH is not the actual in-pot pH, it's lower than that which puts you well into lock-out pH,.... the best way to measure is with a proper pH probe, something like the Accurate 8 works well (love mine!), or a more $$ electrode bulb type like Blue Lab's unit.... otherwise, there is an improved method and calculation in the colored section above this one... please read it ans it'll expalins some things too! meantime, getting that accurate pH reading is key,.. might be a flush is in order, with 7.0 pH water, something with some hardness to it can help because of the mineral (CaCO3) content, which is the mineral that does the pH buffering in solution,... Not sure what the shop guy was thinking, but the soil is not bullet-proof for ph buffering, plenty of things can happen to overwhelm what it can so,.....too many influencing factors in play!
tell us about your water source and pH/TDS/EC (hardness), and we'll figure out a flush solution for you,.. You pH meter, has that been calibrated recently? those a touchy things, easily knocked off calibration if not stored right, in the right solution, not allowed to dry out ever, and calibrated using 7.0 at least, I use 4.0 as a double reference.....