Soil texture is one of the most important characteristics for garden plants to thrive. The ideal soil texture is loamy, which means that it contains equal parts of sand, silt and clay particles.
Good quality soil feels smooth and silky when moistened, releasing moisture easily with squeezing. It may also hold its shape but not crack or crust over when dry.
Sandy soil is primarily composed of small, crushed rocks (aka sand) and lacks organic matter. It drains quickly and doesn’t retain nutrients well. The single best thing you can do to improve sandy soil is add plenty of organic matter. Composts, shredded leaves and grass clippings, hay or straw and manure will all help improve sandy soil’s ability to retain moisture and boost its nutrient levels.
If you need to speed up the process of amending your soil, consider using a mulch made from high-nitrogen materials like composted wood bark or shredded twigs. The organic material will decompose quickly and help increase the nutrient content of the sandy soil as it breaks down. Regular application of slow-release granular fertilizer is also critical in sandy soils as nutrients tend to leach out of them very quickly.
The ideal soil for most garden plants is loamy, which means it has a good mix of different-sized mineral particles. It is made up of sand, silt and clay. Sand particles are the largest, and they help to create spaces in the soil that allow air to circulate. Silt particles are medium-sized, and they help to hold water and provide aeration. Clay is fine-sized, and it tends to pack together tightly, preventing water and air from penetrating the soil.
Most gardeners aim for a loamy soil that has about 40% sand, 40% silt and 20% clay. It can be hard to achieve, but it is important because it allows garden-helping organisms to flourish and provides good drainage for plants. You can test your soil’s texture by squeezing a handful of it in your hand. If it holds a firm clump, it is likely clay; if it feels smooth and powdery, it’s silty.
Clay soil is good for shrubs such as lilacs and Boston ivy, but most annual flowers, vegetables and bulbs don’t thrive in it. It has a hard texture that’s difficult to dig and clumps together when wet. It’s also very dense, limiting the amount of air plant roots can get when it’s saturated.
Adding organic matter such as compost, leaf mold, coarse grit and well-rotted manure improves clay soil. Avoid tilling the soil when it’s wet as this will damage its structure, reduce porosity and decrease aeration. It is best to work clay soil in small areas at a time rather than turning over the entire garden bed or plot. Adding sand to clay soil is a bad idea; it will make the soil like concrete instead of improving it.
Soil pH is one of the most important aspects to consider for successful gardening. If soil pH is too alkaline or acidic nutrients can be essentially locked up and unavailable for plant uptake.
The best way to check soil pH is with a testing kit, available at most garden centers or online. These kits are inexpensive and easy to use. Moisten a sample of soil and compare it to the color chart on the kit to determine pH levels. A pH reading above 7.0 indicates the soil is alkaline, while a lower reading indicates the soil is acidic. Certain plants thrive in specific pH levels, such as azaleas, camellias and rhododendrons. Other plants such as boxwoods and hollies benefit from a slightly higher pH level.
Regardless of the soil type, all gardeners need organic matter to improve its texture and moisture-holding capacity. Organic matter is composted material such as shredded leaves, cornstalks and straw, grass clippings, hay, manure or seaweed. The microorganisms in organic matter decompose it into humus, which increases the availability of plant nutrients.
Gardeners can add organic matter to their native soil or purchase a premixed garden mix at a garden centre. If the soil mix contains perlite, a mined mineral that expands to hold air, it helps keep heavy garden beds and containers from becoming waterlogged. You can also purchase individual organic amendments such as vermiculite, peat moss or composted bark.
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