Your grass may not be growing but you still need to keep your lawn clean! If you have trees anywhere near your yard then there no doubt by now that you have seen a ton of leaves. Depending on the types of trees will depend on the size of leaves, amount and the time they fall. In the start of Fall, using your mower to mulch them up will sometimes be enough. As you get further into the year however, you will usually have to pick up and remove the leaves at least 1-4 times. When you mow over them with a mower it turns them into mulch like it does cutting grass. The issues start when there are too many leaves. You will end up contributing to the thatch layer that sits above the root system in the lawn. Some thatch is an ok thing, too much is harmful to the grass. The issues however are going to be delayed and you won’t see the negatives for some time like when the grass is struggling to grow thick next summer. Another issue is when to many leaves start to form a sort of mat on top of the grass. Over time this mat will stay wet and keep the grass wet. This will then lead to rotting of the grass and other possible fungus issues. Just remember to not let the leaves build up to much on your lawn and unless your mower can make them disappear, there are to many and they need to be picked up and removed. Hope this helps!