New growth yellowing between veins, AFTER feeding. Need help!

[DTOM420]

Blue Widow photo in soil about 35 days old. She was under 12/12 for 9 days to sex all the photos but has been back on 20/4 for 5-6 days. She was growing great and then I fed all my girls some Mega Crop (at recommended strengths) in rainwater I had sitting around from the last downpour. I didn’t test the pH the day I fed but it did test 6.6 before. She’s only been under the quantum board LED’s for a couple of weeks. Before that she lived under a T5 fixture. Temp is steady around 76°-78°

All the other plants are doing great and show no issues other than a touch of nute burn on a few tips here and there. So, I don’t know what’s going on. She IS the tallest girl in the tent but the 640w (at wall) LED’s were a good 16”-18” above the top of the plant. But, the affected new growth all seems to be up at the top; or, at least, it’s more severe up near the top. Doesn’t look like what I’ve read light burn looks like - no curling up along the serrated leaf edges. Besides, the lights are at 1/2 power still. I do notice a little malformation (see close up picture) of a few leaves just under the top, where I FIMed a while back. To be safe, though, I did a little more LST to lower the side branches a bit and I raised the lights up another ~8”.

Anyone know what’s going on? Did I over feed? Really scratching my head here.



Leaf deformity close-up:


Side view:


Top view after tying more down:

 

[DTOM420]

Shout out to @912GreenSkell @Waira @namvet25 @Rev. Green Genes @autobeast @Rollin_along for some help

 

[Autobeast]

Shout out to @912GreenSkell @Waira @namvet25 @Rev. Green Genes @autobeast @Rollin_along for some help

arnt aure mate hard to tell. how high are ur lights? any pics. happy growing

 

[DTOM420]

arnt aure mate hard to tell. how high are ur lights? any pics. happy growing

The lights are about 55-60cm above the canopy on 1/2 power.

You said “any pics” - did you see the photos I posted?

 

[Autobeast]

i ment of ur lights and hanging distance. ur feeding them everything they need. so that makes me think has something to do with ur environment happy growing

The lights are about 55-60cm above the canopy on 1/2 power.

You said “any pics” - did you see the photos I posted?

 

[bushmasterar15]

It looks like light bleaching
Light lessens the pigment of marijuana buds. Light bleaching, aka light burn, will cause your plants to become albino as a result of strong LED's and HPS lights that are situated too close to the top of your plant. In this situation, your plant will end up getting an excess of light.

 

[DTOM420]

i ment of ur lights and hanging distance. ur feeding them everything they need. so that makes me think has something to do with ur environment happy growing

I hear ya. I’m kinda befuddled. It’s around 28°C and 56% humidity in the tent. None of the other plants show this or anything else. I’m thinking maybe an over-feeding issue that has locked out some nutrient? I emailed the breeder and he also think it’s an over-feeding lockout. Told me to use nothing but pH’d water for a few days.

 

[DTOM420]

It looks like light bleaching
Light lessens the pigment of marijuana buds. Light bleaching, aka light burn, will cause your plants to become albino as a result of strong LED's and HPS lights that are situated too close to the top of your plant. In this situation, your plant will end up getting an excess of light.

Ok, I’ll raise them more. How far above the canopy would you recommend for a 640w LED? It’s more than 2’ above currently and only on 1/2 power. I can’t remember whether the symptom started to appear before or after it went under the LED; but the timing is pretty close.

 

[DTOM420]

@912GreenSkell @Waira @namvet25
@bushmasterar15

I think I found her/my problem. I fed her today at pH 6.6 and then I checked the runoff....5.5! WTH?? So I checked all the other plants’ runoff and everything else was 6.5-6.7. So the weird leaf coloration has to be a pH-related lockout of the nutes. I made all the soil up together and it’s litter mate is having zero issues and the runoff is perfect. So, I’m wondering if I double-dosed a gallon of water with the pH Down that’s required to take the well water down from 7.8-7.9. If I did that a couple or 3 feedings ago, could I still be seeing those low numbers in the runoff? I don’t know what else it could be - she was as healthy and vigorous as any plant I have until 10-14 days ago.

What should I do from here? I gave her a good drench today with that 6.5 but I’m thinking maybe I should let her dry out some and give her a good drench of our straight well water? Would that help to start balancing out the pH?

She’s still growing, though. Not as fast as I thought she would. Although, I did a lot of LST about the time I’m suspecting I may have over pH’d her. No doubt that’s a lot of stress. Thank God she’s a photo and not an Auto!

 

[BII]

I am far from expert, but I presume you couldn't go wrong continuing to feed regularly, or even more frequently for a bit, making sure to do a good amount of drain-to-waste (excess run-off) each time. That is, keep the contents of the pot fresh.

And if not already, you couldn't go wrong adding a beneficial microbe product or tea.