Yellowing leaves starting in center of leaf, only one plant, top of plant

[Austwelk]

Greetings, first time poster here, long time grower. The first two pics are the problem plant and the third is from a seemingly good plant.

I’m worried about the yellowing that is beginning to invade in the first two pics. It’s not just a difference between chlorophyll 1 and 2, as the paler form of chlorophyll goes fully green as the leaf enlarges. The yellowing is only on the top. Leaves this large should not have the premature type of chlorophyll.

Some care details: happy frog soil, sour diesel feminized strain. I’ve started giving N nutes about two weeks ago. I have not taken a break from the nutes but I did start low and have now increased to the full recommended amount on the label. Perhaps the yellowing is a burn from not taking a nute break? The yellowing is from the center of the leaf outward.

Another possibility is that I turned the ph down too low. On a grow in the past, I had some flowering plants turn yellow and concluded it was a iron deficiency from too high ph. I was giving water ph’ed above 6.0 and once I dropped the ph to between 5.5-6.0, the plants recovered and were beautifully harvested.

Before giving nutes on this current crop, I was ph’ing between 6.3-6.8, but have now dropped to between 5.5-6.0 like I did on that flowering crop that needed a ph drop.

So, have I dropped the ph too early? Or is this yellowing of a result of not taking a nute break? Or did I start giving the full recommended amount of nutes too soon?

Thanks

 

[Austwelk]

I’ll add that I performed my best attempt at a slurry test. That is where you take one part soil and two parts ph7 water, put into container and shaken, let sit for ten minute and then measure the thin part of the water with ph meter.

My result was 6.5. Is it possible to cause a problem with overly acidic nute water (5.5-5.8), even if the soil ph is 6.5?

It is unbelievably difficult to get a clear picture of what I need to adjust based on what I read online. I’ll just be giving plain water at 6.3 ph or so, maybe every other time, with the other times using nutes also at 6.3 and judge from there

 

[Austwelk]

A person on Reddit helped me decide that I may have just been overwatering. I’d been a bit excessive with the fogger, too, keeping humidity between 65-70, which I’ve now read is too high and can cause the plant to not transpire well and not use all its soil moisture, which becomes a problem if I’m dumping more water down there

There were times where the soil was dry when I stuck my fingers in, but still wet on the bottom when I stuck my finger through the drainage holes. I decided to just give light watering in those cases but that may have been a mistake

 

[LoveGrowingIt]

Nutrient lockout from overwatering was my first guess. Let the soil dry to see if that helps. A soil moisture probe/meter costs about $10 and can be very useful.