I'm stumped-- Spots in middle of leaves?

[WhiteWidowGirl]

Hey, guys! I'm in the middle of my 3rd grow (white widow) and I've come across a strange problem I can't find the answer to. Here are some pics I hope will help.

This is the least healthy of the 3 plants. As you can see, she's got some yellowing on the lower leaves. The other two plants are a lush dark green, but they still have the spots:




The spots on my plants are mostly in the middle. They don't seem to focus on the edges:












Most of the spots are pale/white in the middle with a dark edge, but a few are muddy brown throughout like this:





I just don't get it. It doesn't look like nute burn because that usually burns along the edges (made that mistake with my first crop) and these spots are in the middle.

The spots are evenly spread throughout--they're not focusing on the top, so I don't think it's heat. (It's nice and cool in the grow room and the light isn't too close)

I'm careful not to over-water or under-water (again, mistakes I figured out after my first grow). I tested the PH level with a probe that goes in wet soil and it's holding nicely at 7.

The plants are getting 24 hr light; they're about 17" tall, 6 weeks old.

Any clues as to what these spots would be and how to cure it? Any input is greatly appreciated!

[Ganja Guerrilla]

I think you have overdosed the ferts & the plant is locking out some nutes, you may have a PH issue , your probe type PH testers arent accurate and they only test the top few inches, which is leeched with each watering, while the acids & salts will be held deeper and within the rootball

go to my site (see the link below) and watch the streaming PH soil runoff PH and flushing video

get a chemical ph test kit, or a ph meter

complete a soil runoff PH test.......
with PH corrected water (6.5-6.8PH ) pour enough water in the pots so the water runs out the bottom of the pot ...collect & test the PH of this runoff water....post both the watering going in the pots and the runoff ph

[WhiteWidowGirl]

Great website; thanks for the thorough videos. I flushed my plants (their PH was down at about 6.0)

As it turns out, though, the problem was actually spotting from mold. It's cold up here in Washington state, but it's also extremely humid so mold is a constant problem even with plenty of ventillation.


I think I'm going to buy a dehumidifier for my grow room since I think I've done all I can with air flow alone, but the interior humidity of the house is still high.