What kind of deficiency is this?

[Rik]

I have two Amnesia Haze autos growing in living soil. Today is day 37 since the seeds popped. Can anyone tell me what this particular deficiency is and what I should do to correct it? I have been very careful with my pH and I always feed a mixture of spring water and filtered drinking water that works out to be about 6.7. Thanks in advance for any thoughts! Here are the full grow details:

2 x Amnesia Haze autos from Nirvana
Each in a 5 gallon fabric pot
Indoors in a 4x4 tent
Seeds popped and first true leaves on June 9, today is day 37
Soil: Fox Farm Coco Loco with Nature’s Living Soil (“Super Soil” method)
Fed only water, a mix of spring and filtered drinking water that comes out at 6.65 pH
Fertilized with additional living soil top dressing on day 35
Light: Black Dog PhytoMAX-2 600 (615 watts from wall)
Temperature: Low-70s during lights off, mid-80s with lights on
Humidity: Mid-50s with lights off, low- to mid-40s with lights on
Ventilation: 8” system with 710 CFM fan pulling through two separate large carbon filters (one tail end and one inline) through very long duct work, resulting in a nice breeze coming out in an adjacent room, and tent walls sucking in slightly
Small Vornado air circulator inside tent, blowing 24/7 on low, pointed between pots and slightly down to not be directly on leaves
Vornado oscillating tower fan blowjng softly across the full height of the plants for roughly 12 hours per day, staggered 6 on, 6 off, 6 on, 6 off

[CaptainWiese91]

Is it all the leaves ? Or just that leaf ?

[Rik]

That’s the worst one, but other leaves are starting to yellow a little and there are little bits of brown coming through. It’s only on this one plant. The other doesn’t have any spots. I’m going to post more photos of the whole grow for better perspective.

[CaptainWiese91]

And is it only fan leaves ??
My experience with autos is they will start losing the fan leaves some quite early on. And it looks like a natural process to me.
Could be root issue, but if the growth hasn’t stopped or slowed down. I would say it’s a natural process. But I have never grown in a living soil before 🤷🏼♂️ I do have a lot of experience with autos though

[Catfish22]

Study this and see if it helps.

https://www.growweedeasy.com/cannabis-plant-problems/potassium-deficiency

[Rik]

I figured it was probably a calcium deficiency but wanted others opinions. From Nebula’s articles on living soil, she says this is likely to happen and to feed more spring water to add calcium. I’m already planning on doing that when I feed tonight, but I wasn’t sure if this was the unanimous opinion.

[Rik]

[Rik]

It’s Nina that has the problems. Sofie is completely green everywhere. They sure look different for being the same kind of seed, sprouted on the same day, under the same light and everything. There’s about a foot difference in their height, hence the milk crate.

[CaptainWiese91]

Honestly I wouldn’t worry that much 🤷🏼♂️

feed it some calcium to see if it helps, it wouldn’t hurt it for sure.

but it doesn’t look that bad

[homegrown]

You are right Rik, those plants look nothing like each other. Nina is showing lots of sativa tendencies, spindly with thin finger leaves. And Sofie looks to have more indica in her, Fat leaves and bushy. Maybe you got two different seeds? If thats the case, I've found that sativas are a little more picky than indicas. Much less nitrogen for a start. Are you feeding them flowering nutes now? i would.

[Rik]

Hi homegrown. They look completely different. Makes me want to grow just one at a time from now on. They’re both supposed to be Amnesia Haze autos (from Nirvana), which is a sativa-leaning strain. Maybe Sofie is something else. I wouldn’t put it past Nirvana to do that on accident. I’m not feeding flowering nutes (I’m trying for a water-only experience, hence the Living Soil approach), but I did just a day after these photos were taken add a layer of Nature’s Living Soil Flower Power, their flowering-stage fertilizer concentrate, made to be used as a top dressing or a compost tea. I’ve also upped the amount of spring water in the water mixture (and thereby increased the pH from 6.7 to 6.9) in an attempt to increase the calcium and magnesium getting in.