The older leaves on some of my violets are turning yellow and speckled but are not drooping or falling off. The flowers are fine. The leaves appear healthy except for the yellowing. I use 1/2 tsp. every other week of Peters 12-36-14 (no urea) and bottled spring water. I have used this for years. Do I need a change of fertilizer? I use grow lights 8 hours per day. Please see attached photo.
Thanks for your help!