fallen leaves for leaf mold, leaf compost


When the leaves start to fall in autumn, you’re faced with the question of just what to do with all of those dead brown leaves fluttering around. Many people simply rake and bag them to be tossed in the landfill.

But why not turn them into superb sustainable mulch or compost instead? Leaf mulch and compost are free, beautiful, and rich in nutrients and organic matter for your garden.

Leaf Compost, Leaf Mold and Leaf Mulch: Is There a Difference?

Leaf compost is made from dried leaves (a source of carbon) that are mixed with moist, green organic matter (like grass clippings and kitchen scraps) to provide nitrogen and then left to decompose. Compost is usually added to soil to improve soil structure and nutrient levels.

Leaf mold is like compost except that it’s made only with leaves (so no “green” material) and is broken down by fungus instead of bacteria. It can be used the same way as compost (to amend the soil) or like mulch (spread over the soil).

Leaf mulch is also made from leaves but they’re not fully decomposed. Mulch is generally laid on top of the soil as a protective layer; it helps to suppress weed germination, retain moisture, insulate the soil, and reduce erosion. Some leaves can also increase soil acidity as they decompose, but with our alkaline soils that’s generally not a problem.

Why Use Leaf Mulch, Leaf Compost or Leaf Mold?

There are a ton of benefits to using chopped and/or decomposed leaves in the garden (quite aside from the fact that you’re saving them from the landfill).

For example, leaf mulch:

  • is lightweight,
  • decomposes quickly,
  • doesn’t bind available nitrogen in the soil like bark mulch can,
  • suppresses weeds, and
  • it’s attractive.

There are also long-term benefits from organic matter provided by the leaves as they break down, including:

  • improved soil organic content, and
  • increased presence of important soil microbes.

2 Easy Steps to Make Leaf Mulch & Leaf Mold

Just follow these easy steps to create your own ‘black gold’.

Step 1—Collect and shred the leaves

There are several easy options for gathering and chopping up leaves:

  • Rake them up, place them in a large trash can (a metal one is best) filled about half way, and shred with an string trimmer inserted into the can. Be sure to wear eye protection if you do this!
  • Rake them into a pile and mow over them with a mulching mower (just don’t make the leaf piles too deep or the mower will get bogged down). If you have a bag attachment, this will make clean-up much easier.
  • Vacuum them with a leaf blower with a bag attachment. Your neighbors may not appreciate the noise (be aware that some neighborhoods prohibit the use of lawn blowers) but it’s an effective way to collect and shred leaves.

Whichever option you choose, be sure to remove sticks and stones first, and start with dry leaves – wet ones will just clump together and clog your trimmer, mower or vacuum.

If you’ll be using the leaves as mulch, you can simply spread the chopped leaves throughout the garden. This works well but the leaves tend to blow around a bit so you may want to first rake them into a pile and let them sit for a few weeks to “season” (they’ll break down a bit and be less likely to get wind-blown).

Don’t be afraid to pile leaf mulch high – 6 to 8 inches is good.

If you’re creating leaf mold, go to Step 2.

Step 2—Store the leaves

Place the shredded leaves in a pile, in an empty trash can, in a wire bin or composter, in a large bag – anything that will hold them and prevent them from blowing around. The Compost Sak from Smart Pots works exceptionally well for this. Just be sure that the leaf pile is at least 4-feet high and wide to generate enough internal heat for composting. And don’t pack the leaves tightly; good aeration helps the composting process.

Add a little water to moisten the pile (but don’t turn it into a soggy mess).

And that’s it. Just leave the pile until spring and you’ll have a plentiful supply of leaf mold to use as a mulch or soil amendment. If you’re feeling energetic, you can turn the pile periodically over the winter to aerate it and speed up the decomposition process.

A well-tended composting leaf pile will take 4 to 8 months to fully break down the leaves. Expect the pile to shrink. The final product should be dark, soil-like and crumbly; if it smells bad then it’s not yet ready.

So this fall, don’t remove all that “garden gold” from your yard. Use those leaves and you’ll be rewarded with fertile, rich leaf mold and mulch made possible by your own yard!