Currently advertised on television and in home improvement stores are “winterizer” fertilizers. There’s good and bad about winterizer fertilizers. It’s good that they are emphasizing fall and late fall fertilizer. These fertilizers usually contain the same amount of potassium as nitrogen (nitrogen is the first of the three prominent numbers on the bag while potassium is the third). Though potassium is important for your turf, it is unnecessary to apply on lawns unless a soil test reveals that you need potassium. Thus widespread potassium application when not needed is bad. Most winterizer fertilizers suggest application sometime between October and December depending on where you live and this is good. However, their recommended rates are generally too low and that’s bad. The last application of the year should be near the final mowing, consist of a quick release N source (listed as urea or ammoniacal nitrogen) and be applied at 1.0-1.25 lbs N/1000 ft2. The bottom line is be careful what you buy, apply only nutrients that are needed, and apply when recommended locally.