Identifying the Texture of Your Soil

In order to know what type of amendment will best help you create rich loam, you must first identify whether the texture of your soil is primarily clay, silt, or sand.

First, let’s deal with the characteristics of each type of soil.

Because clay soil is made up of very fine particles, its disadvantages are that it compacts easily, drains poorly or not at all, and tends to crust over. When clay soil is extremely dry, you will hardly be able to make a dent in it even with a shovel. The purer the clay soil, the more easily it compacts thus leaving very little space for air; obviously plant roots may not survive because of this lack of oxygen.

The advantages of having clay soil is that it is a very rich soil, and it drains slowly; thus, nutrients don't get leached out.

Organic amendments such as ground bark, peat moss, or leaf mold improve dense clay soils by physically separating the fine clay particles without holding moisture. A good ratio is roughly 50/50.

Sandy soil is the opposite of clay soil in that it generally drains quickly because its particles are quite a bit bigger thus leaving more air pockets between particles. As a result, sandy soil tends to lose nutrients quickly.

To improve the texture of sandy soil, add a spongy organic amendment such as peat moss. Spongy particles fill the open spaces between the sand particles, so moisture and nutrients are not leached out as easily or quickly. A good ratio is 2/3 amendment and 1/3 soil.

Silt soil is made up of particles which are bigger than those in clay soil but smaller than those in sand. Since high-silt soil tends to compact, preventing deep root penetration, it too benefits by having spongy organic amendments such as peat moss added to it. Again, a good ratio is 2/3 amendment to 1/3 soil.

A higher ratio of organic material to sand/silt is good as the organic matter tends to break down faster due to faster drainage (more oxygen). Since organic material helps to hold onto water and nutrients, it's almost impossible to add too much. Generally speaking, all soils, even clay soils, benefit greatly by adding composted organic matter to it.

Testing for Texture

1. The most basic soil texture test is to pick up a handful of moist soil, roll it into a ball, and squeeze the ball lightly. If the soil feels slippery and your fingers leave an impression in the surface, you are dealing with clay soil. If the soil feels gritty and forms a loose ball when you squeeze it, there's a significant sand content. If the soil feels greasy, then you're dealing with a high proportion of silt. Finally, if the soil crumbles into large particles or is difficult to roll into a ball, it has a well-balanced texture characteristic of loam. In that case you've hit pay dirt, for loamy soils are excellent for gardening.

2. Another test to help you determine the texture of your soil is to visually compare the proportions of sand, silt, and clay. To do this, you first half fill an ordinary quart jar with your soil and then add water to the top of the jar. Securely close the jar with a cover and shake until the water and the soil have become thoroughly mixed. Then set it on a flat surface for 24 hours.

After 24 hours, check the layers: the sand proportion will be at the bottom, the silt will hover in the middle, and the clay will be towards the top. By seeing what you have the most of, you can get a rough idea of whether your soil texture is clay, silt, or sandy soil.