Anyone identify this deficiency?

[oldsmokey]

Merry Christmas I am new here my 1st grow in 10 years. I woke up to this dark spots on a few leaves and some yellowing not sure what is going on any help would be appreciated.

First two pics of brown spot and yellowing on same plant
Second pic of two other plants with possible pest damage looks like something eating leaves but i don't see any pests.

5 weeks old from germanation
Medium - Promix HP
PH - 5.5- 5.6
Using veg nutes every watering 75% strength not watering until thoroughly dried

Thanks in advance for any help

 

[Cultivator]

is promix coco or soil?

 

[oldsmokey]

is promix coco or soil?

Promix is Peat based with peralite added I have read on here to treat it as hydro as far as pH goes

 

[oldsmokey]

Anyone have a guess?

 

[nivek]

well, ph can certainly cause similar conditions,, i have no idea what yours should be but i might suggest it is a bit low?? only because i had a low ph issue and it produced similar results on my plants,, till i upped my ph a bit

could be other things as well,, did you get the leaves wet while the light was still on??

 

[oldsmokey]

I was thinking of raising the pH to about 5.8 on next watering. I don't think I got the leaves wet when the lights are on.

 

[CannaCola]

up your PH for sure. sounds like you have everything under control.

hydro i run 5.6 to 6.1
promix run 6-6.5 typically.. not quite hydro ph, not quite dirt ph. works for me

 

[Calvados]

Hi. I don’t use promix, but I think you should check the watering. I know that coir is never suppose to dry out. If promix is the same, then that’s your problem. I use Canna Terra specifically because I can let the soil dry out before watering.

 

[CannaCola]

drying out would cause wilting if it got too dry, and they bounce back almost immediately.

promix isnt like coco for that.