I have never cut back my ferns, didn't know I was suppose to. I just watched a short video and it explained the reason to cut back the ferns was so that when the new growth comes out later in the year it will not be mixed in with the tired looking old growth. The video suggested Valentines day as a good time to cut back all the ferns.
Most of my ferns, being they are grown outside in the garden don't really need cutting back because the old fronds just sort of naturally fade away.
