Late season fertilization is still possible if the turf is still green and soil temperatures remain above freezing.  Photosynthesis and root growth will continue (although at a reduced rate) under these conditions.  With soil temperatures for most parts of the country below 50F a fertilizer with more quick release nitrogen would be suggested.  A quick release nitrogen source is not depended on soil temperatures for release and thus more readily available for root uptake.

 On sandy soils the rate of late season nitrogen applications should be considered.   Recently published research from the University of Connecticut has found that nitrate leaching increases considerably with late season applications.  Cooler temperatures and thus slower turf growth decreases nutrient uptake.  In situations where leaching is a concern, reduce the rate and use a slow release nitrogen source.