You may have noticed that fall grass growth has started to slow as we approach the middle of October. How does the grass know that it is October? Well, it really does not have a clue. Grass, like all plants use the weather to grow. We are starting to get into average temperatures that are cooler.
Cool season turf grass (the kind that we have in West Michigan), the leaf blades typically grow when the air temperatures are somewhere between 55 and 70 degrees. Outside of that range, the leaf blade growth is slowed or stopped.
However, the roots grow when ground temperatures are between 50 and 65 degrees. That lasts for a good part of the early to mid fall season. Root growth is what the focus should be on when it comes to feeding your lawn in the fall.
The fertilizer application in the fall is the most important application your lawn will receive all season. As the temperatures allow for root growth, the fall fertilizer application is focused for good root growth. By creating strong roots in the fall, your lawn is better prepared for the coming growing season.
Many times it is thought that the last fertilizer application is a waste because there is not much leaf blade growth as a result, and the lawn is covered with leaves, so why bother with fertilizer. That is correct about minimal leaf blade growth, but the focus is on the roots. That is where it needs to be.
Fall grass growth is not focused on the blades, but it should be focused on the roots as we are in the fall season. Making sure that the grass has a good base to grow from for the coming spring will help to produce a better lawn.