Discolored, dry & dead leaves @ 5 weeks

[Gurtgurt]

Hello,

Here we are like 3 days ago:

And here is the plant today:

One other plant has a similar thing but less severe:

Please find the history and environment of the plants here. This affects only 2 of 4 plants. I watered plain, non pH adjusted tap water yesterday. The problem already existed before then but not as severe.

The big leaves are dry and break toward the end. Didn't expect things to progress that quickly.

One thing of note: I had a long work day and the humidifier ran out of water. They probably went several hours at 30pct humidity and saw a max of 80 deg F. The other plants are just fine.

Edit: one last thing: I did top yesterday, including both affected plants!

Any ideas? Appreciate the help.

 

[visajoe1]

have you fed them anything yet? looks like she's eating herself a bit, low P

are the pots sitting in runoff after water?

 

[Gurtgurt]

Have not fed anything yet. They have been in new FFOF and recently up-potted. This was even present to a minor degree when they bad one was still in it's starter container:

(Note the bottom most leaves -- this was 4 days ago)
Not sitting in still water

After searching specifically for phosphorus deficiency, that is a definite possibility. I have fox farm Big Bloom bat guano & worm casting liquid; I'll try adding it at a high concentration next watering.

 

[Gurtgurt]

I searched for P Deficiency & how to address. Online sources say to add worm castings/guano. I thought I had some of this extra, but no. Another method is add high P fertilizer or super phosphate or something. Unfortunately money tight right now, as per usual.

The two previous plants are the same but maybe a little worse. As of yesterday my 2 other clean plants are showing the same symptoms:

Please see my journal linked in OP for complete timeline.

I gave the 2 worst plants from first post just a taste of bloom fert 2-8-4 at night, then the next evening fed all 4 with 0.5 tsp/gal veg fert 6-4-4 two days ago. Nothing dramatic since, but this blight does develop rapidly.

I am starting to see root tips poke out the bottom of these pots' drain holes and will transplant to 3 gal as soon as I can afford new dirt.

Any other pro tips? Thanks Jeff.