HELP! Light green spots on leaves! What is this?

[D.A.A.S.69]

That can't be good blowing cold air on your plants. Can you exaust outside, an use indoor air for your plants ?
On your leaves, if the new growth looks good I wouldn't do anything, if not I'd do a simple flush. No big deal in coco.
But I would still get a heat mat an put under my fabric pots, just to be safe.Young plants don't need nearly as much light as your using.

 

[Bartholomew]

Actually I was worried about the cold air too at first but the air coming from the intake isn't that cold which was a surprise.
I can't exhaust outside.
I think I need to clarify how my room is built. Basically isolated plastic bubble. Outside air intake. Exhaust right now is purely by air pressure which pushes the air into the house from the grow room. As I said, the temps inside the room are quite warm. 20.5C - 26C, that's summer temperature.

Regarding lights, right now they are a bit over 3 feet from the canopy. Two fans are oscillating over the canopy. Lux are between 20 000 - 40 000 which should be optimal at this stage, correct me if I'm wrong on this.

Regarding new growth, the weird thing is that only 2-3 plants are showing the light green spots on a few leaves, the rest are looking normal. The only similar symptom I found on the net was tobacco mosaic virus.

 

[D.A.A.S.69]

To be honest with you, I wouldn't do a thing but watch em close, if it continues an it bothers you, do a flush.
I don't worry over a few spots like that,unless it gets worse, then I'll flush, it's hard to grow a plant ,without a few ugly leaves. Although I've got an auto that's 35 days old, an every leaf it ever grew still looks great, but that's rare. She's healthy.

 

[Bartholomew]

Yeah I'm probably over thinking things. Well thanks anyways for your input.

I'm suspecting bad ph at root level though although I measure the runoff collected from all 9 plants in one tray and it's 6.0. Gonna measure with a soil ph meter in a few days.

 

[Bartholomew]

By the way, did you take a look at my plants and room in the main topic? Would appreciate if you could give your feedback

Link in my signature

 

[DoctorJohnson]

Those leaves look mildly heat stressed (the curling).

 

[D.A.A.S.69]

Yes I did, they are young an don't need much but water an food at the proper ph. Give them a chance to grow an get their roots growing down. Worst thing you can do is try experiments on them, let em grow 4-5 days an see what they look like, if still bad, flush..
They might surprise you. Good Luck. Nothin to worry about now.

 

[MadMike]

I was thinking heat stress as well, but maybe light burn adding to it? The spots do look odd though. Not a great match for light burn.

Looking at it again this morning, I'm wondering if the spotting is early stage phosphorus deficiency? Reading your grow, the pH doesn't look like a cause. Could deficiencies be caused by heat stress? Haven't seen anything on heat related deficiencies but it seems possible to me.

 

[Bartholomew]

Hey Mike,

Yeah I thought so too about light burn, but nah. The more I look at it, the more I see TMV. Some plants have it, others don't. All are growing in the exact same conditions.
I probably had a mild lockout, did a flush. New growth seems fine. Still some plants still present the weird spots on new growth while others don't.