Yellow leaves

hey guys, can ne one figure out what the problem is, i cant put my finger on it. the bottom leaves are turning yellow. i have been givinbg them nutes so dont think that it is a deficientcy, even tho it looks like a nitrogen problem. ph is fine too. ne guesses?

this problem is only occuring with plants in the ground, as the ones in pots are doing fine.

thanks

here are some pics od the others plants dotted arounbd the garden which are in pots...

As long as everything else is okay, there might be no need to worry.

Old leaves tend to die off.