The wet summer we had has benefited many things but particularly our trees. If you have noticed, there seems to be a lot more leaves on our lawns right now. The question is what to do with all of those leaves. Leaves can be left on the lawn but there are a few things to know before you finally decide on what to do with those leaves. Do you leave them on the lawn? Do you mulch them and leave them on the lawn? Do you remove them and compost them? What is the best way to handle them?

The answer may lay in what to do if you seem to have too many leaves. The first step to consider is if there are so many leaves it is shading out your lawn. This is our lawns last hurrah before Old Man Winter will put it to bed for the year. The grass leaves are busy working over time in storing food to make it over the winter months. If there are so many leaves that you can’t see the lawn, then it is time to get them off of the lawn. If you are in a situation where you can run the lawn mower over the leaves several times to mulch them down, they can be used in flower gardens and also in your vegetable garden as mulch. You can also compost them which is probably the best place for them to go. There are a few trade offs in doing this as well.

If you decide to leave that fall leaf pile that the kids were building, on the lawn, more than likely you will have a large dead patch on the lawn next spring. This encourages snow mold diseases, voles, shrews and other critters a welcoming place to overwinter. The leaves will also be a barrier for allowing the soil temperatures in that area to warm up so you might have patches in your lawn where the grass is delayed in the spring in getting busy growing. This may allow weeds to invade those areas.

The key guidance is to allow no more than 20 percent of your lawn to be covered up. This doesn’t sound like much, does it? How much nitrogen will leaves actually give you? It depends on the tree! The average amount of nitrogen from leaves from a tree is around 2 percent (A Survey to Determine the Baseline Nitrogen Leaf Concentration of Twenty-Five Landscape Tree Species Ed Perry and Gary W. Hickman). For those arborists out there, this information is handy because they can use it not only to determine what the nitrogen value of tree leaves is but also help identify trees that might be suffering from some sort of chemical imbalance. If you need another reason why to mulch fallen leaves and leave them on your lawn is weeds. It has been shown in several studies (Using Cultural Practices and Leaf Mulch to Control Weeds in Established Turfgrass, Alexander R. Kowalewski, Ronald N. Calhoun, Aaron D. Hathaway, and John N. Rogers III, Michigan State University, East Lansing, MI 48824) that leaving some leaves on the lawn will help to reduce dandelions by up to 80 percent.

You may ask what this gardener does will all of the leaves in my garden? There are some left on the lawn and some are dumped and spread out on my perennial gardens. I also compost quite a bit of them along with using some left over leaves in my vegetable garden too. In the spring, I pull back the leaves because they do create a mat on top of the soil in the perennial gardens and I place this material into my compost pile. As the season progresses, I use this compost as a side dressing to my plants.

For more information on using leaves on the lawn, please go to http://blog-yard-garden-news.extension.umn.edu/2018/10/should-i-mulch-or-bag-my-leaves-this.html#more. For more information on gardening, you can contact me at s.dejaeghere@me.com