That does appear to be plant chlorosis or a lack of chlorophyll that has as one cause a lack of iron in plant tissue. There are, however, numerous other reasons why the plants have that chlorosis and this article may be of some help in diagnosing what that may be.

http://extension.illinois.edu/focus/index.cfm?problem=chlorosis

What did a good reliable soil test say about the soils pH and major nutrient levels?

kimmq is kimmsr

im sorry but i see nothing wrong with that plant.. in the second pic ...

it is not unusual to lose some of the oldest.. lowest leaves.. during the season ...

i dont see the little one..

ken

Hey guys, thanks so much for the initial feedback.

To be fair, I've only done at-home tests with the soil, and everything looked good, maybe a bit acidic with the ph, but the NPK seemed good. Right now, the plant doesn't seem to be suffering much from this, but during the "winter" we have here in SoCal, it was worse. Not that it's helpful, but because I'm a nerd, I took a look under a microscope..

Also attached is the lil guy who seems to get this a lot.

Btw, kimmsr (aka kimmq), your comments in other posts have got me far, thanks!