A free, readily-available resource!
First, what exactly is leaf mold?
Leaf mold (leaf compost) is quite simply decomposed leaves. It is one of the best soil amendments you can use to bring new life to your soil. It has a texture much like compost, dark brown to black, and has an earthy aroma. Leaf mold acts mainly as a soil conditioner by improving the soil structure. It WILL NOT add nutrition to your garden plants but it will enhance the condition of your soil creating a soil that is rich in calcium and magnesium and is less prone to compaction.
Benefits of Leaf Mold
- It's easier to make than compost as there are no mixing of greens and browns.
- It increases water retention. In areas where droughts are a constant threat, this can be really important. It really soaks up the rain. It has been known to hold up to 400% of its own weight in water.
- It can be used as an effective weed barrier.
- It provides a great habitat for soil life including earthworms and beneficial bacteria.
- It will lighten up clay soil.
- It will help prevent sandy soils from drying out too fast.
- If you leave the leaf mold piled up for two plus years as many gardeners do, you will end up with humus. Humus is that dark rich crumbly organic matter that covers the forest floor – Nature's compost. It improves the soil structure and holds nutrients and moisture.
- It's a free renewable resource!
Why not just add the leaves to the compost pile?
While it's okay to add thin layers of leaves into your normal compost, too many Autumn leaves, even if they're shredded, will tend to mat together and prevent air flow in the pile and you'll notice the pile will start to smell. It's a better practice to decompose the leaves in a separate bed then incorporate the leaf mold directly into the soil.
Why not add the leaves straight into the garden beds?
This is something many gardeners choose to do, however the leaves may take more time than one season to decompose into that wonderful crumbly texture.
Most leaves are slightly acidic as they fall, but as the leaves break down into leaf mold, the pH goes up into a more neutral range. This is the main reason gardeners prefer to let the leaves sit over the winter to decompose as opposed to placing them straight in to the garden. Applying leaf mold will not correct a pH problem if you have one, but it will have a moderating effect.
How to Make Leaf Mold
Leaf piles can be made at any size, but it's recommended to pile the leaves 3 feet wide by 3 feet high, water the pile and let sit. You can use rounded chicken wire to hill them up to the 3 feet.
Some gardeners recommend filling a plastic bag with leaves and cutting holes in the bags for air flow. For a small batch of leaf mold, this may work well. If you have the space for a 3 by 3 area, I see no benefit to the plastic bag.
How to Use Leaf Mold
- Acid-loving plants like Hostas, Blueberries, Azaleas, and Rhododendrons will love the boost they get from leaf mold. Mulch up to 4” around the plant but away from the trunk.
- For perennial plants, use leaf mold as a mulch top dressing for winter protection. The best time to mulch with leaf mold is after the first few frosts. Remove any dead vegetation and apply 2” of leaf mold, then turn it into the garden or container next spring.
- For Ornamental Plants. Pile leaf mold 2-3”deep around the plant, within an inch of the base.
- Just like regular compost, use the bottom of the leaf mold pile first as it will be the first to decompose.
- Mix leaf mold into soil in containers for its ability to retain water
Leaf Mold for your Veggie Gardens
For vegetable gardens. You can turn the leaf mold in at the end of the season which will create a soil that is less prone to compaction. Leaf mold is rich in calcium and magnesium which are essential for healthy vegetables. It is particularly good to incorporate in areas where you're growing carrots and members of the cabbage family. Remember that it does not provide the needed nitrogen, phosphorus and potassium.
Apply up to 4”of leaf mold between rows and 2-3”around plants and till in at the end of the growing season.
Best Trees for Leaf Mold
Leaves of any trees can be used. The smaller the leaves, however, the faster they will break down. Smaller leaves like Birch, Alder and Japanese Maple only take six months to break down.
Using different types of leaves together will help balance and improve the quality of the finished product.
Here at Sunset Hosta Farm we have no shortage of leaves, so we take advantage of this valuable free resource by using it both as a leaf mold amendment to our container soil and garden soil and adding it to our compost pile
Ways to Speed up the Decomposition ProcessLeaves naturally decompose slowly to furnish plant nutrients gradually and improve the structure of the soil beneath. Because leaves are basically carbon, it takes longer to break down than, say, grass clippings which are nitrogen rich.
This three-bin system is ideal for aerating the leaves as they decompose by moving them from one bin to another. Other ideas:
- Run over the leaves with the mower before stacking. Small pieces always decompose more quickly.
- Add nitrogen such as grass clippings, fresh manure or blood meal.
- Turn your leaf pile over every few weeks.
- Cover the pile with tarps to keep leaves consistently moist and warm.
Use leaf mold in containers for its ability to retain water
For perennial plants in containers or in the ground, you can use leaf mold as a mulch top dressing for winter protection. The best time to mulch with leaf mold is after the first few frosts. Remove any dead vegetation and apply 2” of leaf mold, then turn it into the garden or container next spring.
For Ornamental Plants. Pile leaf mold 2-3”deep around the plant, within an inch of the base.
Here at Sunset Hosta Farm we have no shortage of leaves, so we take advantage of this valuable free resource by using it both as a leaf mold amendment to our container soil and garden soil and adding it to our compost piles.
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