I feel dirty. Do you feel dirty? It is a dirty time and I don’t mean the good kind. Let’s just embrace it, talk dirt and see if it feels therapeutic. After all, according to my Soil Science teacher the soil is the basis of life.
So what is soil? Soil is a very thin and fragile layer of life-supporting material through which all major environment elements cycle; we can’t live without it. We are rooted in the soil and we need to take care of it.
I am not going to try to dazzle you with fun facts about soil science and I am not trying to make this an entertaining way to sneak in a little dirty education. I do, however, want to share some of the more practical things—the essence—that I took from the class. Like most gardeners in the Catskills I think of our soil as a nightmarish mixture of clay and rock. However, if you get rid of the “two rocks for every dirt” aspect, the soil isn’t really all that bad. The farmers who grew (grow) crops here probably knew that, so they tilled the soil and moved the rocks to the sides of the fields. Most of what we have in our area would classify broadly as a silty clay or silty clay loam. However, if you are in a valley—or better yet a flood plain— you will most likely have loam or sandy clay loam: loam being soil that has a nice balance of clay, silt & sand with at least 5% organic matter.
So what is clay? Is there anything nice to say about it? Clay is made of very tiny particles and therefore has a lot of surface space. This large amount of surface space and its chemical makeup results in a lot of water attraction and retention as well as binding lots of nutrients. Since our soils have a lot of clay with its capability to hold nutrients, they don’t require water as often and can be good for planting. The issue, however, is the “hard factor.” Clay has a propensity for bad drainage because the water can’t pass through the fine particles easily via the normal laws of gravity. It either tends to saturate or run off. It becomes especially problematic here because nearly everything is on a slope (double the trouble). This leaves us with a challenge because plants (like people) are generally quite unhappy in mucky clay where there is no room for oxygen! Nor do they enjoy dry hard clay if the water runs off down the hill.
Soil scientists—yes this is a profession—are big on what they call the soil structure and texture. While they can talk technically about it for hundreds of pages, I will attempt to condense. What we want is a soil that can hold enough water and oxygen to support the plants that we want to grow. Sounds simple, but our biggest enemy in this regard is compaction. Compaction occurs when we walk on, or run machinery over, our soils (especially when they are moist), thereby decreasing the size of the pores in the soil and resulting in decreased oxygen, water absorption and drainage. The best way to avoid compacted soil is not to compact it in the first place! Put paths in your beds so that you don’t have to walk on the planted areas. In order to create a good texture for your soil, you can add organic material (compost) and possibly some sand or small gravel to add larger and varied-sized particles.
Tilling the soil is often seen as the solution for compaction and improving the soil texture, but tilling also disrupts a good soil structure and should be avoided once you are on the right path. Tilling disrupts the communities of organisms that form there and over time make a healthy structural and chemical base for your garden. Adding compost on the surface is sufficient (it doesn’t need to be tilled in), as it leaches into the soil and breaks down over time into humus which is the finest most basic form of organic material.
Another great way (and a relatively easy way) to have proper soil texture is to create it yourself in raised beds. This is often simpler than trying to dig a bed, take out all of the rocks and work other material into the clay. What I do most often is to dig out the grass and weeds to get out the roots and then create a new bed by filling in and mounding it up using a lot of organic material mixed in with the original soil. To avoid run-off of needed water and possible erosion it is a good idea to create terraces when you are dealing with a slope. Or at least create a rougher soil texture running parallel to the slope of the hill.
I know, this column feels like serving vegetables. They can’t all be pizza and dessert!~
Mel Bellar is the owner of Zone4 Landscapes and a passionate Andes gardener