Infiltration

I follow a Denver blogger and recently he posted something interesting: 

Read the full post here. The gist of it, paraphrased is: 

People are constantly saying to mulch with organic matter to conserve soil moisture, well, the soil has to be moist in the first place. In a region where it doesn’t rain all day and all night, but just for a couple of hours, organic matter impedes infiltration.

Rock is the answer, just like in real life where these plants grow. The rocks let the rain infiltrate down to the soil.

So add rocks to any little area where smaller plants like agastaches and salvias are growing to kind of mimic reality. Not more compost.

from The Miserable Gardener

That explains a lot. 

My own observations have consistently frustrated me that all my nice added compost turns hard and clumps under the damp wood mulch, and water doesn't seem to penetrate very far down, no matter how much I irrigate or hose water.

He explains just what I have been seeing. I need infiltration -- rocks -- spread around plants to help brief but deep watering to move, rather than sit pooled just under the wood chips.

It should be small sized pea gravel, not mixed into the soil, just at the surface. 

I now have an installation project to do this winter.