Sand / by Karie Luidens


The results of the “jar test” are in, and it looks like my soil is... brown? 

I’m new to this. 

The goal of shaking it up in water and measuring the layers that settled out the next day was to determine the soil’s texture, that is to say, the size of its mineral particles. I actually researched the concept of soil texture a few years ago for a piece I wrote about Pueblo pottery, so I knew the scale would go something like this: 

62.5 µm - 2 mm   =   sand
3.9 - 62.5 µm   =   silt
< 3.9 µm   =   clay

In other words, soils that are mostly sand have the largest particle size, which means they have the least surface area and the most porous space between particles. This makes them light and grainy, and allows air to circulate and water to drain quickly. Plants generally have an easy time putting down roots in sandy soils, but they might not find much in the way of moisture and nutrients when they do. 

Clays are at the opposite end of the spectrum, with microscopic particles that pack together so tightly they can look and feel like a single smooth mass. They retain rich nutrient levels, but that nutrition may not be available to most types of plants as their roots struggle to infiltrate the dense material, which can be rock-hard when dry and smotheringly heavy when wet. 

The goal for vegetable gardeners isn’t just the happy medium that is silt, whose medium-sized particles offer a mix of sand and clay’s pros and cons. Instead, ideally your soil consists of a combination of all different particle sizes aggregating into a fluffy, well-aerated, damp-but-draining, nutrient-rich loam. 

Unfortunately, based on my jar test, I think I’ll be contending with sandy soil out back.