OTHER reasons for yellow leaves

This is not a big deal, but I had problems with wet seedlings getting a good start, particularly so with a Lebanese. Everyone is now transplanted and growing much better, and all seem to be drying out nicely, but the Lebanese has now developed yellow tips on its lower leaves. It had that before, but water was the obvious culprit. I don't think that can be the problem now. My question is: can other things cause yellowing leaves or leaf tips? (ProMix Potting Soil + a little perlite and a little vermiculite.)

Thanks for any wisdom.