Part 1 - Overview
Why is leafmould so special?
You might think, "Why not just add these leaves to my compost?". While composting (obviously!) is a fantastic practice, leafmould offers unique advantages:
- Superior soil conditioner: Unlike compost, which is rich in nutrients, leafmould's primary strength is improving soil structure. It helps clay soils drain better, and sandy soils retain moisture. Studies show it can increase water retention by over 50%. Please take a look at my post about mulch.
- Haven for soil life: leafmould creates an ideal environment for earthworms and beneficial bacteria, enhancing your soil's overall health and vitality.
Making leafmould is easy
Creating leafmould is incredibly simple. Here's how:
- Collect Your Leaves: Gather fallen leaves from your garden or local areas, avoiding those from busy roads that might contain pollutants.
- Choose your method: wire cage: Construct a simple cage with chicken wire and posts. This allows for good air circulation.
- Reusable bags: Pack leaves tightly into sturdy bags, puncturing them for airflow. This is a great space-saving option.
- Wait and reap the rewards: Leafmould relies on fungal decomposition, which takes time – usually one to two years. Ensure the leaves remain damp, watering them occasionally, especially during dry periods.
- Repeat this every year to ensure you have a steady supply of leafmould.
Speeding up the process
There are a couple of ways to accelerate the decomposition:
- Shredding: Running over leaves with a lawnmower before composting speeds up the process by breaking them down into smaller pieces.
- Turning: Every few weeks, turn the leaf pile or shake the bags to increase air circulation. Covering the pile with a plastic sheet can help retain moisture and warmth, further accelerating decomposition. Check out my post on air, the secret weapon in composting.
Types of leaves
Most deciduous (annual falling) leaves are suitable for leafmould, but some decompose faster.
- Quick decomposers: Birch leaves break down relatively quickly with their thin structure.
- Slow decomposers: Larger, thicker leaves like those from horse chestnut trees benefit from shredding before composting.
- Conifer needles: Pine needles decompose slowly and create acidic leafmould, which is ideal for acid-loving plants like rhododendrons and blueberries. Collect these separately.
- Leaves to avoid: Avoid leaves from trees like walnut, eucalyptus, and cherry laurel, as they contain growth-inhibiting chemicals.
Using Your leafmould
Once decomposed, your leafmould is ready to enrich your garden.
Young leafmould (1-2 years):
- Mulch: Spread around shrubs, trees, and vegetable gardens to suppress weeds and retain moisture. Learn more about mulch.
- Soil improver: Dig into the soil. It helps clay soils drain better, and sandy soils retain moisture.
- Autumn lawn top dressing: Provides nutrients to soil microbes, promoting healthy grass growth.
Well-rotted leafmould (2+ Years):
- Seed sowing mix: Use on its own or mixed with sharp sand for a free seed-starting medium.
- Homemade potting compost: Combine with sharp sand, loam (soil), and garden compost for a nutrient-rich potting mix.
Leafmould: A Gift That Keeps on Giving
By embracing leafmould, gardeners can transform fallen leaves into a valuable resource. It's a simple, sustainable practice that nourishes your garden and reduces waste, all while being completely free.
So, grab your rake, gather those leaves, and embark on your leafmould journey today.
Part 2 - Factors that influence the breakdown of leaves into leafmould
Here are the factors that influence the breakdown of leaves into leafmould, according to the sources you provided:
Leaf Type
The type of leaf significantly impacts the speed of decomposition. Smaller, thinner leaves like birch break down faster, while larger, tougher leaves like chestnuts benefit from shredding beforehand. Evergreen leaves and conifer needles decompose much slower than deciduous leaves and should be chopped and only added in small quantities. Pine needles, however, create acidic leafmould suitable for mulching acid-loving plants like rhododendrons and blueberries.
Leaf Size
Chopping or shredding leaves speeds up decomposition because smaller pieces break down faster.
Moisture
Consistent moisture is crucial for the fungal and microbial activity that breaks down leaves. Regularly watering the leaf pile, especially during dry periods, ensures optimal moisture levels. Inadequate moisture can significantly slow the decomposition process.
Aeration
Providing adequate airflow within the leaf pile is essential for efficient decomposition. Using a mesh or wire cage structure or puncturing plastic bags containing leaves ensures sufficient airflow. Turning the leaf pile every few weeks further enhances aeration and speeds up the breakdown.
Time
Leafmould formation is a slow process, primarily driven by fungal decomposition, unlike the faster bacterial decomposition in a compost heap. While some leaves may break down in a year, most require around two years to decompose fully into usable leafmould.
Temperature
Covering the leaf pile with a plastic sheet can help keep the leaves warm and moist, speeding up the process. Steam rising from the pile also indicates rapid decomposition.
Additives
Adding grass clippings to the leaves can increase the nitrogen content, potentially aiding decomposition. Using a lawnmower to collect leaves naturally incorporates some grass clippings.
It's important to remember that leafmould formation is a natural process, and these factors work together to break down leaves. While you can control factors like leaf size and moisture, others, like time, are inherent to the process.
Part 3 - Leafmould vs. other composts
Leamould is great, and so is compost, but how do they differ?
Leafmould primarily relies on fungal decomposition, while other compost utilises bacteria for a faster breakdown. This means leafmould takes longer to mature, usually around two years for complete decomposition. This is different from regular compost, which depends on bacteria for a quicker process.
Leafmould excels as a soil conditioner, improving structure and water retention, while compost focuses on boosting soil fertility (It does also helps with soil structure and water retention!). Leafmould doesn't offer as many nutrients as compost but significantly enhances the soil's ability to hold water, up to a 50% increase, according to studies. It creates an optimal environment for beneficial organisms like earthworms and bacteria.
Leafmould is best made solely from deciduous leaves, although some tougher evergreen leaves can be added to speed up the process in regular compost. However, certain tree leaves, like walnut, eucalyptus, and cherry laurel, should be avoided entirely due to their plant growth-inhibiting chemicals.
Leafmould offers versatility with uses ranging from soil improvement, mulching, to creating potting mixes. You can enhance soil structure and water retention by incorporating it into garden beds. In contrast, younger leafmould, about one to two years old, can be used as a surface mulch to suppress weeds and gradually enrich the soil. For potting mixes, finely sieved leafmould can be combined with garden soil or sieved compost, which is especially beneficial for container gardening due to its excellent water retention properties.
Have you considered speeding up your composting efforts? Why not consider hot composting?
Part 4 - Leaf Mould FAQ
Please find my quick, frequently asked questions about leafmould below!
1. What is leaf mould?
Leaf mould is created from decomposed leaves, making a fantastic soil conditioner for your garden. Unlike compost, which relies on bacteria for decomposition, leaf mould primarily uses fungi, resulting in a slower breakdown process.
2. What types of leaves are suitable for leaf mould?
Deciduous tree leaves, such as oak, beech, and hornbeam, are ideal for leaf mould. Avoid using leaves from heavily trafficked roads or those known to release growth-inhibiting chemicals (e.g., walnut, eucalyptus). Evergreen leaves are better composted due to their long decomposition time.
3. How do I make leaf mould?
Two simple methods exist:
Method 1: Open Pile/Bin:
- Collect leaves in a pile (ideally, at least 3ft wide and tall) or a bin.
- Moisten the leaves thoroughly.
- Allow to decompose for 2 years, occasionally turning and moistening.
Method 2: Plastic Bag:
- Fill a sturdy bag with dampened leaves.
- Seal the bag, puncturing holes for air circulation.
- Store in a shady spot for 2 years, adding water when necessary.
4. How can I speed up the decomposition process?
- Shred leaves before adding them to the pile or bag.
- Turn the leaf pile every few weeks or shake the bag to introduce air.
- Cover the open pile with a plastic sheet to retain moisture and warmth.
5. When is leaf mould ready to use?
Young leafmould (1-2 years):
- Mulch: Spread around shrubs, trees, and vegetable gardens to suppress weeds and retain moisture.
- Soil improver: Dig into the soil. It helps clay soils drain better, and sandy soils retain moisture.
- Autumn lawn top dressing: Provides nutrients to soil microbes, promoting healthy grass growth.
Well-rotted leafmould (2+ Years):
- Seed sowing mix: Use on its own or mixed with sharp sand for a free seed-starting medium.
- Homemade potting compost: Combine with sharp sand, loam (soil), and garden compost for a nutrient-rich potting mix.
6. What are the benefits of using leaf mould in the garden?
- Improves soil structure.
- Enhances water retention in both heavy and light soils.
- Provides a beneficial habitat for soil organisms like earthworms.
- Acts as a soil conditioner, promoting healthy root development.
Summary
Here are the key takeaways from my guide
- Leafmould vs. Compost: Leafmould primarily uses fungal decomposition (slower process), making it ideal for improving soil structure and water retention. Compost relies on bacteria (faster process) and is richer in nutrients, directly boosting soil fertility.
- Making Leafmould: Collect deciduous leaves (avoiding those from walnut, eucalyptus, and cherry laurel), shred for faster decomposition, and store in a pile or container, ensuring adequate moisture and aeration.
- Benefits of Leafmould: Enhances soil structure, increases water retention, creates a haven for beneficial soil organisms, and can be used as mulch, a soil improver, or a component in potting mixes.
- Using Leafmould: Young leafmould (1-2 years) is suitable for mulching and soil improvement, while well-rotted leafmould (2+ years) can be used in seed sowing mixes and homemade potting compost.
I hope you have enjoyed my guide!
Adam
I'm Adam, the founder of Compost Guy. I'm passionate about empowering people to embrace composting! Whether you're a seasoned composter or just starting your journey, I'm here to help.
