Seeing the light from atop a mulch pile |

Seeing the light from atop a mulch pile

Tom Glass
Vail, CO Colorado

I have a confession to make. When I first came to the valley, I thought I was doing people a favor by saving them some money by not aggressively advocating the use of soil amendments when planting. I came from an area of the country where soil amendments were necessary only to increase the size of a sale, not to guarantee the survival of a purchase.

Then one day I dug – scratch that – I chipped, and hammered, and picked, and chiseled and cussed out five small holes to accommodate five bushes in some clay and shale soil so tight and poor it would scarcely grow sagebrush stumps. It took me a couple of hours.

I got pagan religion that day. Now I’m an evangelist for mulch. Allow me to make a convert of you. This is my manifesto.

If you look up, it is likely you will see that we live in an area whose predominant features are rock. Rock doesn’t absorb much water, nor hold many nutrients other than the ones of which they are made. It’s tough to plant into solid rock. My thoughts on the matter are don’t even try. If you must, then jackhammer or blast out a hole and fill it with composted pine bark mulch, topsoil and manure. Be sure to add a drain, or plant bog plants.

If a potential water feature is not what you had in mind, then pile atop the rock a huge berm of composted pine bark mulch, topsoil and composted manure ” and plant into the pile. There’s nothing new here. It’s done all over the valley.

It’s also tough to plant into powdered rock. If you look down, it is likely you will see clay. Clay is composed of very fine, uniformly-sized particles of minerals that result when rock decomposes. Add water to clay dust and you get a greasy substance that, once saturated, holds water. It holds it because it can’t take up any additional water, and it isn’t releasing any, either. Clay is used to line the bottom of ponds to keep water from leaking out. In constructing below-ground structures, very fine clay ” known as bentonite clay ” is often used to line the below grade walls to keep them water-tight.

You may ask yourself why this matters. It matters because water has a hard time moving through clay. The mineral particles hold onto water tighter than a plant’s roots can pull them away.

Furthermore, there are few and small pore spaces in clay. Clay particles are so uniform that they pack together tight. Water is drawn through pore spaces in soil via capillary action; a process where one water molecule being attracted to a mineral molecule lining an open space, a pore, brings a cohesive group of additional water molecules along with it, and they fill the open space. Water filling a void is available to plants. Water stuck to a mineral particle probably is not.

How do you plant successfully into clay? Add composted pine bark, topsoil and composted manure. Break up the clay with irregular-sized bits of humus ” organic matter. This creates pore spaces that water can be drawn through, and adds organic matter that holds water ” but not so tightly as to make it unavailable to plants.

How much compost and soil do you add? Approximately, a lot. Dig big, wide holes and fill them with compost. Don’t dig the hole any deeper than the ball of the tree, because the tree will settle deeper into the hole as time passes. Not so good.

You can, however, pile up a mixture of composted pine bark mulch, topsoil and composted manure in and around the hole and plant partially below-ground and partially above-ground. Surround the root ball as if you were planting it into a small hill. You will probably have to add composted mulch every year, but your plantings will live.

A good majority of the soils here will not support the trees and shrubs you most want to plant. In order to succeed, you will need to create a more favorable environment. Imagine that: creating a more favorable environment than what is already here. It’s hard to believe. I didn’t when I first arrived. I do now.

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