Leaf mold is an excellent, free soil amendment. It is easy to make, simple to use, and has a huge impact on soil health. So if you have not got your leaves up consider making leaf mold.
What is Leaf Mold?
Leaf mold is the result of letting leaves sit and decompose over time. It is dark brown to black, has a pleasant earthy aroma and a crumbly texture, much like compost. In fact, leaf mold is just that: composted leaves. Instead of adding a bunch of organic matter to a pile, you just use leaves.
Benefits of Leaf Mold
You may be wondering why you shouldn’t just make compost. Why bother making a separate pile just for leaves? The answer is that while compost is wonderful for improving soil texture and fertility, leaf mold is far superior as a soil amendment. It doesn’t provide much in the way of nutrition, so you will still need to add compost or other organic fertilizers to increase fertility. Leaf mold is essentially a soil conditioner. It increases the water retention of soils. According to some university studies, the addition of leaf mold increased water retention in soils by over 50%. Leaf mold also improves soil structure and provides a fantastic habitat for soil life, including earthworms and beneficial bacteria.
How to Make Leaf Mold
There are two popular ways to make leaf mold, and both are ridiculously simple. The one thing you’ll need to keep in mind is that leaf mold doesn’t happen overnight. Leaves are basically all carbon, which takes a lot longer to break down than nitrogen-rich materials such as grass clippings. The decomposition process for leaves takes at least six to twelve months. The good news is that it’s basically six to twelve months with very little work on the gardener’s part.
The first method of making leaf mold consists of either piling your leaves in a corner of the yard or into a wood or wire bin. The pile or bin should be at least three feet wide and tall. Pile up your leaves, and thoroughly dampen the entire pile. Let it sit, checking the moisture level occasionally during dry periods and adding water if necessary.
The second method of making leaf mold requires a large plastic garbage bag. Fill the bag with leaves and moisten them. Seal the bag and then cut some holes or slits in the bag for airflow. Let it sit. Check the bag every month or two for moisture, and add water if the leaves are dry.
After six months to a year, you will have finished leaf mold. Impatient? There are a couple of things you can do to speed up the process:
- Before adding leaves to your pile or bag, run over them a couple of times with your lawn mower. Smaller pieces will decompose more quickly.
- Use a shovel or garden fork to turn your leaf pile every few weeks. If you are using the plastic bag method, just turn it over or give it a firm shake. This will introduce air into the process, which speeds decomposition.
- If you are using the pile or bin method, cover your pile with a plastic tarp. This will keep the leaves more consistently moist and warm
How to Use Leaf Mold
Leaf mold has several uses in the garden. You can dig or till it into garden beds to improve soil structure and water retention. You can use it as mulch in perennial beds or vegetable gardens. It’s also fabulous in containers, due to its water retaining abilities.
Leaf mold is simple, free, and effective. If you’re lucky enough to have a tree or two (or ten) on your property, you’ve got everything you need to make great garden soil.
Burning fallen leaves used to be standard practice across North America, but most municipalities now ban or discourage this due to the air pollution it causes. The good news is that Sanford offers curbside pickup of leaves, which they then turn into compost for park maintenance or for sale commercially.
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Brenda Larson is the Horticulture Agent for North Carolina Cooperative Extension in Lee County