How To Compost Leaves So They'll Enrich Your Garden's Soil

If you have leaves accumulating on your lawn and in the garden, instead of raking them up into piles and putting them in bags to set on the curb, may we suggest composting them. Leaves are full of nutrients that will benefit your flowers, shrubs, and trees and are good for the soil.  Composting creates a closed-loop system by keeping and putting back rich-nutrients into the ecosystem.

We spoke to two gardening experts about why composting leaves is important and how to compost, along with some tips for making a successful pile. 

Why Compost Leaves?

Leaves are a nutrient-rich resource, just like branches, twigs, paper, and kitchen scraps, and when broken down provide important nutrients for your garden. Composting leaves is a natural way to recycle and put back minerals and nutrients into the soil. Plus, composting saves money—you don't need to buy amendments, such as manure, compost, or humus, to enrich the soil. "Leaves are a free resource and nature’s way to return nutrients to the earth," says Stephanie Turner, Clemson Extension Horticulture Agent and Master Gardener Coordinator for Greenwood County. And composting leaves means less going to the garbage dump. "One of the benefits of composting leaves that is overlooked is its sequestration of carbon, which keeps the leaves from going into landfills," says Bailey Van Tassel, author of Kitchen Garden Living. 

To Shred Or Not Shred Leaves

Once you've gathered leaves, you can shred them or put whole leaves in the compost. Shredding leaves isn't required but can make the process easier and faster in the long run. Shredded leaves shorten the breakdown process in the compost. "Shredding leaves reduces the time it takes for the decomposition process and makes it easier to mix and turn the pile," says Turner.  

Don't worry if you don't want to or can't shred them. "It is perfectly fine to compost whole leaves if you don’t have the means to shred the leaves," says Turner. When adding whole leaves, mix them into the compost pile to avoid matting. "Matted layers can impede moisture and airflow that the organisms in the pile need to do their decomposition work," she says.

How To Build A Compost Pile

A leaf compost pile can be done in a designated compost bin or by making a heap, ideally shaded from wind so it doesn't blow away. "The level of nitrogen, the size of the leaf, and the moisture level will determine how quickly it will transform into compost," says Van Tassel.

1. Mix Greens and Browns

   Dried leaves, along with dead or other dried plants, wood clippings, and shredded paper, including newspaper and cardboard are considered browns, also known as carbon. Meanwhile, greens or nitrogen consist of grass clippings, kitchen waste, and manure. "[Leaves] are a good source of carbon for the compost pile to offset the nitrogen introduced by vegetable scraps," says Turner. "The whole process works best when you focus on the balancing act of composting the optimum ratio of browns to greens and proper moisture and aeration." The recommended ratio is 30 parts carbon to 1 part nitrogen based on weight or 30:1, she adds.

   Place a layer of greens, then browns, then greens and so on to create a compost pile. "Layering compost is important because it allows for better aeration," says Van Tassel. "Save up your greens and browns and then add them to the compost pile in layers, it will decompose more effectively," she adds. 

2. Make a Good-Sized Pile

   Aim to build a pile that's larger than three feet high and wide but not bigger than five feet tall or wide. Place it in a sheltered location where it won't be affected by wind or too much sun. 

3. Have Smaller Pieces

   The size of all the material influences how quickly it decomposes. "The smaller the pieces you start with, the faster the composting process will go," explains Turner. "Stiffer, woody materials should be cut into smaller pieces to speed things along."

4. Water the Pile

   Compost needs nitrogen and carbon, along with oxygen and water to decompose properly. If it rains, you likely don't need to add any water. Check the pile to ensure that it's moist but not soggy or sopping wet. If a pile is too wet or too dry it will impede the breaking down process. 

5. Turn the Compost

   How often you turn the pile factors into how soon you'll have compost to use in the garden. Turning the pile aerates the compost and helps with the decomposition process. A well-made pile will become hot in the middle.  "Turn the pile to move material from the outside of the pile into the center so all parts of the pile get a turn in the ‘oven’ at the center of the pile," says Turner. 

   Turning the pile daily will speed up the process. "Skipping days can add weeks to the process," says Turner.  

6. How To Know When Compost Is Ready

   When compost is ready, you'll notice that it looks similar to soil. "It will be a rich, dark brown color and the center of the pile will no longer heat up significantly," says Turner. Pick up some compost, which will be crumbly, and sniff it.  "It will smell clean and earthy like the forest," says Van Tassel. Check for important critters, too. "Earthworms will be present in a good compost pile," she adds.  According to Turner, "If it is done well, a 3-foot pile can be ready in two to three weeks. 

Alternative For Using Leaves

Leaf mold

Consider making leaf mold if you don't want to make a leaf compost pile but want to get all the nutrient benefits. "Create leaf mold by letting piles of leaves break down for six months to a year," says Turner. "Leaf mold makes an excellent mulch and soil conditioner."

Leave the Leaves

Piling up leaves in an area in the garden, such as around trees or placing them carefully around plants as a form of mulch, is an easy way to put them to use and create a closed-loop system in your yard. "A layer of leaves around trees or shrubs or even in the perennial bed will serve as natural mulch and harbor overwintering butterflies and moth chrysalis and cocoons," says Turner. Also, consider spaces in the yard where you gather the leaves and let them be, which creates important habitat for wildlife, including insects, worms, amphibians, birds, and more, while the leaves slowly decompose. "If there are areas in the landscape where you can ‘leave the leaves’ this creates a more natural habitat for the smaller critters in your garden," she adds.

Tips For Creating A Successful Pile

Never Add Diseased Leaves

A crucial component of a healthy compost pile is to avoid adding diseased plants, including mildew or weeds, to avoid spreading it throughout the garden when the compost is ready. "While many weed seeds and disease organisms are killed by the high temperatures at the center of the compost pile, there is a high possibility that some will persist," says Turner. As an example, Van Tassel says, "If you had a bad year with vine borers, burn those plants as opposed to composting them, or else you compromise the quality of your compost." 

Create Your Pile Once

There is a tendency to continue adding layers to the pile when you have more greens and browns to add but this extends the timeline. "Adding new material to the pile restarts the clock," says Turner, "So have a holding area for material to add to the next batch of compost." Create your pile, turn it, and then begin again once the compost is ready. 

Cover the Pile

Compost that is decomposing properly will heat up in the middle. If this isn't occurring, put a cover on the pile so the temperature doesn't' dissipate. "A sheet of plastic tucked around the top of the pile can help keep in warmth and moisture," says Turner. On rainy days, a cover also prevents a pile becoming too wet or soggy.