The best mulch is provided by nature. In a well-designed organic garden, this is one of the only mulch types that magically appears in our beds in autumn, protecting the soil over winter, and breaking down throughout the following spring and summer until a new batch magically appears in autumn.

 

The Best Mulch Number 1

Of all the mulch types, by far the best for organic gardening is: leaves! They do absolutely everything right. That's why when we're designing our gardens we want to make sure to use plants that make a lot of leaves - not just evergreens - and we want to design the beds to catch all of these leaves.

Those that fall on the lawn and non-garden surfaces can be raked into the gardens or mulched right on the lawn.

If you don't have enough leaves, your neighbors will usually be happy to give you theirs, since they would otherwise have to rake them up and dispose of them. In many cities, you can rake your leaves to the curb and a big truck will come by to pick them up. But why would you want to give the best mulch ever away unless you have too many?

Ironically, some organic gardeners do this and then buy the leaves back as leaf mould in the spring. Leaf mould is just leaves that have been slightly decomposed. Leaf mould is one of the best mulch types, too, but in most cases, the gardener would have done much better to save the money and keep the leaves in the garden over winter where they can protect the soil.

If you have a thick enough layer of leaves in your garden (2" to 4" is nice), many weeds will be smothered. You will still get some weeds, but they will be so easy to pull that it won't matter. You can just drop them back on top of the leaves to become part of the best mulch ever.

Some people think leaves are not one of the most attractive mulch types for the garden, but is a forest floor unattractive? Or is the forest floor covered in 2 inches of bark?

We've been conditioned to think that bark mulch or bare soil is the most aesthetically pleasing, but if you covered your organic garden in a rainbow of autumn leaves, I think you'll see it differently, especially now that you know all the benefits they provide.

When we remove the leaves, we are breaking nature's cycle and creating more work for ourselves.

So leaves are the number one best mulch.

 

The Best Mulch Number 2

There is one other organic gardening material that doesn't take the place of leaves as the ultimate of all the mulch types, but it is beneficial to have as well. It's called a living mulch, i.e. plants. A living mulch is a dense plant cover on the soil, especially low growing "cover" crops.

These can be annual crops (also known as green manures) that we plant in our vegetable gardens to protect the soil during certain times of year and to provide organic matter to the soil, or perennial plants (also known as groundcovers) that live permanently in our ornamental gardens underneath our flowers, shrubs and trees.

A good goal is to make sure all of your soil is consistently covered with plants, and cover crops help achieve this goal. Plants send out hormones in the vicinity of their roots that tell weed seeds not to grow.

As long as your organic garden is dense with plants and leaves (the best mulch ever), and your lawn is dense with healthy grass, those weed seeds will mostly stay dormant and you have a whole list of other benefits to which you can look forward.

Mulching All Your Leaves - There Are Exceptions

It is possible to have too many leaves if you have a lot of big trees or if your beds are already covered in groundcovers and you don't want to totally smother them. In that case, you may just have to compost them or give some away, to a friend or to the city, although I have mulched 12 inches of leaves into some lawns with great success.

Actually, when I was a kid, I recall my dad would pile a bunch of leaves in the back of the pickup truck (we lived in the country), head down the street to where there were no houses, drop the tailgate, and hit the gas. It was so much fun watching the leaves get caught by the wind and cover the sky like a thousand red and yellow butterflies. In hindsight, I have no idea why we did this, but it was fun at the time.

I know someone reading this is wondering about oak leaves. I've never had a problem with the fact that oak leaves don't break down quickly. I've always enjoyed that about them because it just means my mulch stays around longer. And nope, they don't acidify the soil. But again, if you have too many, don't force it.