Like any good recipe, you need to start off with basic knowledge of the ingredients you are using. This extends to agriculture and gardening. The two parts of this recipe is your soil, what it brings to the party, and your plants, what it needs to party. This three (3) part blog series begins with what types of soil particles does it contain in it. Parts two (2) and three (3) will cover how well does it allow water to pass through the soils (drainage), with some simple fixes for problem areas, and what is the PH, along with the four (4) essentially elements that are the building blocks of plant nutrition: Nitrogen (N), Phosphorus (P), Potassium (K), and Sulfur (S).
Soil has four distinct types: Sand, Silt, Loam, and Clay. A parcel of land can contain one all four of these soil types. Let's work from the largest to smallest particles.
Sand comes in with the largest particles of earth. It is typically found in hotter regions and near larger bodies of water. Sand is an excellent drainage material as it does not absorb water and allows it to pass through. It does act as an excellent filter for catching larger pieces of debris. Because Sand doesn't hold or absorb water, it is among the hardest soil types to grow in.
Silt has medium sized particles composed of mostly of rocks and can include a combination of soil types listed. Silt is easily displaced by water and is found in "wet" environments such as rivers, lakes, and areas with water run-off. It does retain water well making it a functional growing medium.
Loam is the most common soil type that includes medium sized particles of Sand, Silt, and Clay, making it the idea growing medium. Water retention can vary based on the mixture proportions and will affect the nutrients found in it.
Clay has the smallest sized of particles in it. When wet, it can be shaped, formed, and retains water. Once dry, it creates a near water-resilient barrier. Clay is an excellent base for a strong root system. This is why we frequently line the bottom of our growing beds and pots with clay.
Soil also has different layers to it, which can vary in depth and composition, even in the same geographical area. As we live in the Texas Hill Country, we actually see almost all soil types on just our 10 acres. Closer to the highway we have maybe 1"-2" of top soil before we hit caliche, a hardened natural cement of calcium carbonate that which acts at a binder to any of the above listed soil types. As we come further back in our property, heading toward Medina River, our soil depth increases slightly. Near one of our buildings, and the chicken coop, we can go about 12" down before hitting caliche. At the back of our property, where the rain run-off tends to stop before reaching our neighbor's slightly higher elevation, our soil depth reaches up to 14" in places. Our soil depth creates unique challenges for our property along with those of our neighbors. After our holiday break, we will dive into Gardening Methods and which ones work best where.
How did we determine our soil depth? Some people will take a metal ruler and stick it into the ground to see how far down it goes. We took a more constructive, or destructive, method of letting our kids get some excess energy out by digging holes for us until they hit caliche. From there we used a ruler to gauge the depth of the hole. As a rule of thumb, most plants need at least 2" of soil to be able to grow. Trees will need a large/deeper head start. For plants and trees that we have added to the property gave a starting depth at least twice of the amount needed and at least a 24" diameter circle based on final growth of the plant or tree. "Depth at least twice of the amount needed" required research on our part to understand if a tree has a deep or shallow root system along with understanding the needs of the trees in that area which create our soil food web aka guide to companion planting. When we filled the holes back in, it was with a combination of soils with the exception of clay. Once many of our trees have become established, their root system gets strong enough to breech the caliche and into the water table below our property.
Tune into part II where we dive into water drainage and common fixes.
References:
https://www.teachstarter.com/us/search/soil/ (Paid teaching resource)
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