bottom leaves of collards turning yellow
I planted some collard seedlings in containers late September and they were doing pretty good for the most part but I've noticed the last week or two the older bottom leaves keep turning yellow/brown and dying. I've been fertilizing them with a diluted 5-1-1 fish emulsion (1Tbsp/gal) about every two weeks.
After searching through the forums for a bit, I found one post saying yellowing bottom leaves means N deficiency and another post saying too much N so I'm a bit confused there.
There are two pictures below. First one taken 10/13 and looks pretty good. I've since removed the mulch after finding what looked like termites under the mulch of my loan tomato plant. The second one was taken today (10/29) and you can see the yellowing bottom leaves. Maybe because I removed the mulch they're not consistently staying wet?
Thanks for any help!