The texture of the soil in your garden impacts the plants you grow. Soil texture is typically sandy, clay or silty, or a blend of these texture types. The texture of the soil is determined by the size of the particles. Clay and silt have have a small particle size, while sandy soil is made up of larger particles. Loamy soil is a blend of sandy, silty and clay soil mixed with nutrient rich organic matter like decomposed leaves. Once you know your soil you can add amendments to create the ideal growing environment.
Loam: The Perfect Bed
Loamy soil drains well, retains moisture, holds nutrients and provides a stable base for plants. It has a mix of fine clay particles, silt and coarse sand particles mixed with organic material -- like partially broken down leaves, grasses, needles, bark, roots and all the other decomposed parts of plants that go into making good soil. A true loam soil is made up of relatively equal parts silt, sand and clay. While loamy soil is naturally high in nutrients, adding compost before the planting season helps keep loamy soil in top shape.
- Loamy soil is rich and dark in color. The organic material often has an earthy, musty scent.
- Within the category of loam, you can find sandy loam, clay loam and silty loam
depending on the ratio of soil particle size and textures it contains.
An example of a sandy loam would be soil with a particle structure of at
least 50 percent sand, and the rest a blend of silt and clayparticles.
Adding Amendments to Loam
Use plant-based seasoned compost to amend loam soil before planting. A 1- to 2-inch layer, added annually, adds new nutrients to the soil. Mix the compost with the soil, turning it 6 to 8 inches deep. Blend loam until it is smooth by breaking up clumps as you go.
Sand: Fast-Draining Soil
Sandy soil is usually low in fertility. This is caused by the large, coarse particles that make up the main structure of sandy soil. Nutrients, instead of getting trapped in the soil, wash through when watered. Sandy soil drains fast, causing it to dry out rapidly.
Sandy soil feels coarse and rough with visible particles. It is often light in color and gritty.
Amending Sandy Soil
Adding sphagnum peat moss to sandy soil helps improve water retention. Peat moss is porous, causing it to absorb and hold water. Use a 1-inch-deep layer spread evenly over the bed, then dig it with the soil 4 inches deep. Another good amendment for sandy soil is compost. Compost adds decomposed organic matter to the soil, helping absorb water and improve fertility. Dig 2 to 3 inches of compost 6 to 8 inches deep with the soil. Turn the bed and blend the sandy soil with whichever amendment you choose.
Clay: Poor-Draining Soil
Air circulation and drainage is generally poor in clay soil. The minuscule soil particles in clay cause water to get trapped, making the garden waterlogged and perpetually damp. Overworked clay soil also compacts, forcing the fine particles together. When clay dries out, it crusts over, or turns rock hard, further starving plant roots of moisture, air and nutrients.
Clay soil is typically grey and feels sticky. The fine particles are difficult to distinguish from each other. Clay soil is easily molded into shapes.
Amending Clay Soil
Use bulky organic material to turn clay into loamy garden soil, and use sand to add coarse particles to the existing fine particles. Amendments like decomposed leaves, leaf mold, decomposed straw, tree bark and wood chips work well. For the sand, use clean garden sand; anything from the beach will be too salty to use. Avoid peat moss because it holds water, slowing drainage in already poorly drained soil. Start with a 3- to 4-inch-deep layer of bulky amendments and dig them into the top 6 to 8 inches of the bed. Then spread sand 3 to 4 inches deep and work that into the top 6 to 8 inches of the soil.
Silty Soil: Fine Soil with Good Drainage
Silty soil, which comes from river beds, is a fine particle soil similar to clay. It has the compaction problems of clay soil, but won't get waterlogged the way clay does. Silty soil is high in nutrients, and, once amended with compost, it is rich and well suited for growing.
Silty soil is slick feeling compared to the sticky feeling of clay soil.
Amending Silty Soil
The main challenge is to keep silty soil from compacting, while adding organic matter to improve nutrients. Compost is ideal for silty soil. Add 2 to 3 inches of compost, then turn it in 6 to 8 inches deep.
Before digging or amending any type of soil, make sure it is damp but not muddy. If the soil sticks to your boots and tools in big clumps when you go to work the bed, wait a week or two for it to dry out.