Making Leaf Mold

pecan leaf in the spring
pecan leaf in the spring

Trusting in the experience of the master gardeners who responded to my last post (thank you!) and the magnolia’s own evolution I decided to mulch the tree with its own leaves. The leaves have been spread out to cover most of the area from trunk to drip line. I am hoping these leaves will actually perform a few jobs simultaneously:

1. Moderate the soil temperature & hold in water and soil as any mulch will;
2. Protect the magnolia’s roots. Unlike more forgiving trees, magnolia roots are delicate and even small disturbances (looking at you Mr. Letter Carrier) can kill a tree; and,
3. Smother the St. Augustine grass circling the tree. Bonus: maybe the nitrogen in the grass will help turn those leaves into a nice compost.

But what to do with the mountains of pecan leaves? And when I say mountains I mean piles much taller than I stand.

in the past I have used them to make compost and as a mulch. I am liberal with their use and I’ll be honest — I still have a mound left over from last year. So this year I am going to try something new: DIY leaf mold.

Leaf Mold is Not Compost

So I learned today that leaf mold is not compost. Compost is a product of bacterial processes; leaf mold is created by fungi. Compost can be made pretty darn quickly. I get multiple harvests most years. But leaf mold apparently takes a long time — about 9 months in warm places and up to three years in colder areas. If the leaves hurry up and fall from the trees right now my leaf mold will be ready for next September.


Basically, just add water. The leaves need to be moist for the fungus to grow. Some people get fancy and build cages to hold the leaves. Some people put the leaves in bags that have air holes. I am going to be lazy and just keep them in a big pile. I think I -might- lay a tarp on top to help keep the moisture in.

Benefits of Leaf Mold

Leaf mold does not contain much in the way of the major nutrients (nitrogen, potassium or phosphorus) but it usually contains a lot of trace minerals. I plan on using the whole batch in a new planting area. I am not going to do any digging there even though it is mostly compacted clay and virtually every site on the internet tells me I am supposed to dig it up to loosen and ‘work’ the soil. I would rather let the leaf mold do all the hard work for me. Its texture should immediately improve the tilth but most importantly leaf mold has the potential to stimulate biological activity in the soil. A lot of the area where the leaf mold is destined to end up looks inert and barren to me.  I have poked a few holes into the clay but only rarely have I found any sign of subterranean life. I am hoping the leaf mold can repair that. My long term goal is to create a mini forest around the pecan tree and hollies already present. Is there a better way to begin than building humus? If so, do tell.

Of course everything I’ve said here is theoretical. Think it will work? It feels like a slow approach to gardening in a world where I could just go to the hardware store and have something installed over a weekend.

20 thoughts on “Making Leaf Mold

  1. I also let leaves lie where they fall on the beds and borders, but I have an shrubby corner of the back garden where leaves can be left in piles. I’m guessing I have to deal with a much smaller quantity of leaves than you, though.


  2. By blowing oak leaves off our drive and into beds we inadvertently set up leaf mold production sites in various spots out front. I’d always thought it irritating because I couldn’t easily start seed (no soil contact without digging under the leaves) in those areas, etc. but after years of the practice I’ll affirm – the soil life under those leaves is pretty lively. And a deep enough layer suppresses weeds. It is a slow process, yes, but a lot of what works best in gardening takes more time than effort. I did see it suggested that we refrain from using only one type of leaves to avoid that monoculture/pest support dance that can occur. Not a problem here – I get most of my neighbor’s red oak and pecan leaves blown over for free.


    1. Thank you. That’s a really good tip about using a variety of leaves. Noted. Slow and steady is fine by me. Afterall, I can’t be in too much of a hurry since it has taken me so many years to even rethink the use of that space. The only times I have ever gone out there has been to cut the grass or rake up leaves.


  3. I get excited over compost (plants grow so much better with it, I call it black gold) and I use leaf mold for top dressing. My soil over the years has improved greatly. Nature knows how to do it, so I just follow her lead.


  4. We used to have black walnut trees that left leaf piles all over taller than me….too many. I like your idea. Now in this garden I can leave our leaves on the beds to decompose which they do by the end of the garden season.


  5. I’m impressed with your perseverance and plans. I can’t imagine that the leaf mold would a bad thing in a garden or along/mixed with soil, because like compost, leaf mold happens. Keep us apprised of its progress.


    1. One thing I just learned that I thought was exicitng was that leaf mold improves the water retention of soils in a remarkable way. Much more than the addition of compost or of mulch. Now I wish I had been doing this all along.


  6. I just got done transferring the compost from the bin to my wife’s vegetable garden. She will let that sit, along with some of this year’s crop of leaves until spring and then to it all in.

    I’ve never heard of leaf md being good stuff. I guess I won’t worry when it forms on the parts of the compost that don’t get stirred. Thanks for the information.


    1. I realize some people have allergies and setting up a leaf mold pile would be out of the question for them. We’ll see if I am as enthusiastic about the project as time passes!


  7. We stayed in Taos, NM in late Sept at the home of a master gardener. She had 4 compost piles going at once. They were corralled by bales of straw and covered with tarps to hold moisture. The first had the most recent additions of organic matter. The second was a few weeks older and stirred. The third was older still and stirred more. The fourth was ready to use compost material. Beautiful stuff. From what I saw, she only kept it moistened and covered. She said she did no special things to it.


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