ItÂs a good question. There are a lot of opinions on the subject including mine which IÂll give you now. Many suggest two Autumn applications of fertilizer, one early, one late. I personally fertilize on October 15 and then follow up with another after the topgrowh has stopped but before complete dormancy (November 30). I use organic fertilizers for all except the late November application for which I use 46-0-0 urea at the rate of 2 lbs per 1000 Sq. ft. Some believe that late fertilization contributes to snow mold. Indeed it might. I had snow mold last spring but it was harmless and cleared up quickly possibly because of the organics used the rest of the year. In summary, to answer your question, put your winterizer down now and think about another dose around November 30. A search of this forum will reveal lots of posts on the above subject.
Bill Hill