Soil Clay Content

While most the plants I grow go straight into sand, it is necessary sometimes to form a que of volunteers ready to risk their lives in the soilless media. So I pot them in soil.

This activity CAN be rewarding. There is something intrinsically refreshing about putting a fresh bare-root seedling into a dark pot of soil. However, Fortuna conspires to rob one of this simple pleasure.

The problem is that the soils are often formed of a thin layer of humus over a solid mass of pure clay. The humus layer, besides being thin, is a tangled meshwork of roots and leaves that is difficult to obtain in any quantity. And the clay is a malleable, solid mass. Fun to play with, and even efficient at holding onto nutrients, but in its super-abundance it often forms one solid puck in the pot, whose center is virtually impenetrable to water.

There are multiple tests designed to assess the clay-content of soil. Here I review two.


First, if you can take the soil and easily spell the word "CLAY" with it, it is almost entirely made of clay. This test has yet to achieve the status of universal standard, but has much to speak for it. The letters involve circular arcs, perpendicular intersections, and 45 degree intersections. And don't even get me started on that awkward horizontal line near the top of the "A". A litmus test if there ever was one.

Of course, there will always be critics. Some hold onto the old standard, which says that if, and only if, the soil can be used to symbolically represent two interpenetrating realities, is it truly clayey.




However, most feel that this is a waste of time.