Garden
Tip 
For the Love of Leaves
By Anne Lenox Barlow, Horticulture Educator,
Clinton County
For many reasons, I look forward to fall each year. To me, fall weather is ideal. Sunny, warm days and cool nights is what I like. Then there are the leaves – the beautiful, colorful, useful leaves.
Wait a minute? Right now you are probably asking yourself, is that a typo? Did she really just say that her leaves are useful?
Yes, I did. Leaves are one of the best gifts a gardener can ask for. Why? Because they are the most abundant free source or organic matter one can find. One of the most common ways gardeners use leaves is to compost them.
Microogranisms slowly transform leaves into bits of decomposed organic matter that help retain soil nutrients and moisture when the composted leaves are added to a garden. In addition, the composted leaves add small amounts of the 16 different nutrients that plants require back into the garden.
To compost your leaves, you can simply stockpile leaves into a bin or pen. Turning them periodically helps speed up the decomposition process, as does adding some nitrogen. A free nitrogen source is your fruit and vegetable scraps. Just make sure that your compost pile has twice the volume in leaves as it does in food scraps and never add any meat or dairy products. Break these two composting rules, and your pile will start to smell rather foul.
Part of the beauty of leaves, though, is that you don’t have to wait for your leaves to compost. With some shredding assistance from your lawn mower, you can give your leaves useful jobs right now:
1. Leaves make a wonderful fall mulch for your perennial beds and vegetable gardens. The best mulches are porous enough to permit the penetration of air and water to the soil, thus promoting plant health. While not a consideration in the winter for vegetable gardens, perennials, and annual beds, this becomes a factor if the mulch is to be reused in spring in the gardens. Shredding keeps the leaf mulch porous.
And for those more interested in producing compost than leaf mulch, remember that leaf mulch won't remain leaf mulch forever. Think of leaf mulch as compost waiting to happen! That's right: as the leaf matter decomposes, valuable nutrients will be released into the soil and made available to your plants. You can hasten this process by shredding the leaf mulch before applying it. If you don't have a leaf shredder, run the lawn mower over your leaves to shred them.
2. If you want to add to your current garden or create a new garden, leaves should be your new best friend. New garden beds can be made by covering the new garden space, this fall, with 6 layers of overlapping newspaper or a layer of cardboard, covered with 2 inches of compost, and topped with 3 to 4 inches of shredded leaves. By the spring all of this will have killed the sod below and decomposed into a nice rich soil amendment that can then simply be tilled into the soil.
3. Shredded leaves can be used to mulch around cold hardy vegetables such as kale, leeks, carrots, and other hardy vegetables. The mulch will insulate the plants, limiting the amount of winter injury and increasing the length of harvest!
4. If you need to improve drainage or organic matter content in a current garden, you can dig narrow trenches in your existing gardens and fill the trenches with leaves. By late spring, the leaves will have decomposed enough to be mixed into the soil.
5. Research done by Michigan State University reveals that leaves can even be left right on the lawn. The studies conducted by the University left thick layers of shredded leaves on the lawn and allowed them to decompose where they fell. The grass in their studies greened up faster in the spring and grew strong the following summer. Just don’t expect the leaves to disappear from view until the grass starts to grow next spring!
Shredded leaves also work well as mulch for trees and shrubs. To do so use 3 to 4 inches of shredded leaf mulch around the base of the trees, but do not pile the mulch up around the trunk of the tree. A layer of mulch helps to moderate soil temperature fluctuations in the winter, reducing cold-related injuries to shallow roots. The leaves also feed beneficial soildwelling fungi, according to a Colorado State University study.
There is only one word of caution when using leaves in the lawn and garden. If you have a black walnut tree, the juglone chemical in the leaves can cause reduced growth to many plants. These leaves should not be used directly in the garden. They can be used to mulch around a black walnut tree or can be composted. Iowa State University studies have shown that the juglone in black walnut trees in neutralized by composting for 6 months.
If you still want to rake your leaves to clear off your lawn and do not use them for composting or mulching, check with your local town to see if they have a composting service. This way you can share your leaf bounty!