Two main aspects of your soil’s health are its nutrients and its composition- here are a few basics to learn about the composition of your soil and what it means for your plants.
Nutrients include elements and minerals, such as Nitrogen, Phosphorous, and Potassium (NPK), which you can measure using a basic chemical test. Composition effects which kinds of plants like to grow in it and is indicated by its texture. This month, you’ll learn how to test both your soil’s nutrients and composition as well as how to fill and amend the soil in your beds using organic methods.
The ideal soil for growing vegetables is loam, a mix of composted organic matter along with inorganic particles. Loam is dark, rich, moist, and crumbly, and sticks together briefly before falling apart when you squeeze it. Soil composition is classified according to the proportion of sand, clay, and silt it contains. A healthy loam is about 2:2:1, or 2 parts silt to 2 parts sand to 1 part clay.
Silt particles are smaller than sand and larger than clay. Silty soil feels soft, almost silky. The small space between silt particles allows it to hold water and nutrients better than sand. In general, silty soil is good for growing plants.
Sand makes up the largest soil particles, which you can see with the naked eye. Sandy soil feels coarse and gritty. It drains quickly- but sometimes it can be too quick, leaching water and nutrients before roots can absorb them. Sandy soil needs to be watered and fertilized often.
Clay particles are the smallest. Clay soil gets sticky when wet and hard when dry. The great thing about clay is that it holds nutrients and water. Too much clay, however, is not ideal for vegetable gardens because it can be hard to work, drown roots, and become easily compacted.