Is this light stress/burn or something else?

[BalzarDanglin]

I've been really struggling with this one. The other plant in the tent is totally fine and showing no issues. Meanwhile this one keeps fading up top.

I'd unknowingly turned the lights up too high a while back, but brought the lights up as high as I could and brought the light intensity down to around 18 DLI, then very slowly worked my way up to around 25. Since the issue seemed to be progressing I ended up dialing the light back a bit.

I discovered that my local water has next to no Mg (0.6mg/L) vs around 10mg/L Ca, so dosed with epsom salts to (hopefully give it a boost).

I am new to autos so trying to figure out what im doing wrong.

Strain: Samsquanch OG
Age: 48 days from sprout
Medium: Soil - 2/3 Biobizz Light Mix; bottom 1/3 All Mix
Lights: 20/4 cycle; Kingbrite 240W QB (white/red) 3500k. 30" above canopy @ 45% on dimmer. Ppfd 300, DLI ~22.
Environment details: 2.3x2.3x5ft tent, daytime temp 74-77; lights off temp 70-71; RH 48-52 (can go lower but have been slowly bringing it down through the start of flowering)
Nutrients: Biobizz Grow (0.5ml/L), Bloom (approx 1.5ml/L), Topmax (1ml/L), Calmag (0.3ml/L), Algamic (1ml/L).
Watering schedule: Wait until dry, then water around 2L slowly.
Air movement: Inline exhaust fan on controller, small oscillating fan, small circulation fan
Ph: Turns out my Ph was increasing to 7.5 to 8 after letting it vent off chlorine and such. I am now Ph-ing down to 6.5.


Any help is much appreciated.

First pic is from about a week ago. Second from yesterday. Third from this morning.

 

[Olderfart]

Looks like lockout to me, but wait for the gurus to check in.

Good luck with it.

 

[BalzarDanglin]

Thank you

I think its lockout due to pH getting too high. I wasn't pHing water as I'd read its not necessary with organic soil/nutes, but am now doing it.

I'm wondering if a flush with pH'd water (6-6.5?) , followed by half dose nutes might help, but I think it best to wait for others to confirm. I don't want to put the old girl through more than she has been already!

 

[throxic]

I agree with lockout. I'd flush her really good with ph'd water and hit her with 1/2 strength nutes afterwards. Then next feeding up it to 3/4. And finally, the next water, fed her what you normally would. I'd also up the PPFD to 500 since you're flowering, but that's up to you. I run 18/6 and at day 48 I'm usually at a PPFD of 500-700.

 

[MrAutoGrower]

It’s not from a salt build up by the looks of it. Because I can only see one crispy leaf at first glace. The rest are fading out without spotting or so. Looks like a ph issue perhaps. However, based on the tips of the leaves, I’d say you’re adding too Much nutrients

 

[BalzarDanglin]

Thank you.

I was being a pussy with the lights worrying I was burning them, but makes more sense it was lockout causing things.

Question. I watered yesterday. Would you recommend flushing ASAP? I have pHd water ready to rumble but am debating if watering again now would be worse than waiting until dry to flush!

 

[BalzarDanglin]

It’s not from a salt build up by the looks of it. Because I can only see one crispy leaf at first glace. The rest are fading out without spotting or so. Looks like a ph issue perhaps. However, based on the tips of the leaves, I’d say you’re adding too Much nutrients

I started off at half nutes, and never got up to the recommended biobizz dosage. Tips got a bit burned around 3/4 strength, so I backed off again and have slowly been working my way up.

I know Biobizz recommends adding nutes to every watering, but I'm starting to wonder if I should feed every other watering...

 

[throxic]

Thank you.

I was being a pussy with the lights worrying I was burning them, but makes more sense it was lockout causing things.

Question. I watered yesterday. Would you recommend flushing ASAP? I have pHd water ready to rumble but am debating if watering again now would be worse than waiting until dry to flush!

I did the same thing with my lights when I noticed my last lockout, but now that I've recovered from it, I now know it was the nutes/bottom feeding. As for flushing now or the next feeding, it doesn't matter much. If she's locked out, she ain't growing anyways so adding a bit more stress from overwatering will be temporary. The goal is to bring the pH in the medium down to an acceptable range for the roots so she starts growing again. I'm not very familiar with your nute line, but since you're in soil, you could add some beneficial microbes to help buffer the pH. (I use Recharge to add them back in, but any microbial product will suffice.) If done properly, you should start to see her recover in 2-4 days; flowers getting bigger and a greener appearance. Also, just fyi, I use Recharge about every ten days until the 4th week of flower. (For autos, that's in the 50-65 day range.)

Hope you get her squared away. Remember, you learn the most when things don't go as planned.

 

[BalzarDanglin]

Thanks @throxic

I just did a slurry test (granted using wet soil) and the pH came out at 6.4...which is confusing the hell out of me. I'm assuming since soil was wet and last watering used properly pH'd water that is what's causing it to read lower than it probably is deeper down in the pot.

I think it best to properly flush and start from scratch. No point waiting any longer!

I looked into Recharge but it costs an arm and a leg over here! I'm wondering if something like these two things might be useful though:
- The Nutrient Company TNC MycorrHydro - Soluble Mycorrhizal fungi inoculant w/Trichoderma
- The Nutrient Company TNC BactorrS13 - Beneficial Bacteria for Compost Tea, Hydroponics & Horticulture - Soil Microbes

 

[throxic]

Yeah, those are what you're after. For an auto, I would use the MycorrHydro in seedling and veg stages every 10-14 days and the Bactorr every 10-14 days in all stages, until the 4th week of flower (day 50-65 for an auto depending on veg time).