Soil is one of the most essential elements for planting trees. Your soil will determine the overall success and health of your tree. Since different trees prefer different soil types, one needs to be conscious of the soil type in their environment. The different soil types are determined by factors such as colour, texture, pH, and more.
There are mainly 6 types of soils:
- Sandy Soil
- Silt soil
- Clay soil
- Loamy soil
- Chalky soil
- Peat soil
Sandy Soil is light, warm, and dry. It is relatively acidic and low in nutrients. Due to its texture, this type of soil tends to have low water retention. Since they have quick water drainage they are easy to work with. They might need an extra nutrient boost by adding organic materials. This organic matter can also help ensure a better water retention capacity. Trees planted on sandy soils require regular watering and fertilising which can be time-consuming, expensive, and sometimes unsustainable. It’s always best to choose plants that grow naturally in sandy soils such as Grevilleas, Acacias and Banksias. They are perfect for low fertility sandy soils.
Silt soil is a rare soil type with a smooth, slippery soapy texture that is formed by fine sediments and compacts fairly easily. It doesn’t chunk up. The size of the particles this soil has is larger than clay particles but smaller than sand. It is light and has high moisture retention. It also has a high fertility rate. As the particles are fine, they can be easily compacted and are prone to washing away with rain. This type of soil is usually found near water regions such as lakes and rivers. Its pH level can vary from slightly acidic to slightly alkaline. By adding organic matter, the silt particles can be bound into more stable clumps. Most vegetable and fruit crops thrive in silt soil. Moisture-loving trees such as Willow, Birch, Dogwood and Cypress also do well in silt soil.
Clay Soil is a heavy soil type that has the benefits of high nutrients. It is rich in organic matter. It provides essential compounds and minerals to trees ensuring that they can grow better. Clay soil is made of over 25 percent clay, and because of the spaces found between clay particles, clay soils hold a high amount of water. It remains wet, sticky and cold in winter, but dry and smooth in summer. It is easily identified during summer since it tends to have cracks. Clay Soil is very compact, making it hard for water and air particles to go through easily. It is in the optimum pH range of 5.5 to 7.0. Trees such as white pine, Norway spruce, white cedar, red maples, poplar and European larch grow very well in clay soil.
Loamy is soil composed mostly of sand, silt, and a smaller amount of clay. Its mineral composition is about 40–40–20% concentration of sand–silt–clay, respectively. This combination of soil types creates the perfect soil texture for plant growth. It also helps curb the downside of each soil type, since loamy soil is fertile and it drains water properly. It has soil particles with high acidic pH and calcium levels but may require additional organic matter. Loamy soil is also a relatively affordable solution that works great for trees. Loamy soil is great for planting red oak, white and green ash, sugar and red maple, white cedar, European larch, white spruce, and poplar.
Chalky (lime-rich) soils are often shallow, stony and free-draining. It can be heavy or light. This type of soil is easily identified by the presence of white lumps. It is made up of calcium carbonate and alkaline. This soil type tends to lack the necessary nutrients to support some kinds of trees and shrubs. The yellowing leaves (chlorosis) and poor growth in chalky soil can be attributed to the tree not being able to absorb iron and manganese by their roots. Chalky soil can be improved by tilling in lots of organic material like composted pine needles, manure, compost and/or peat moss. One can also pre-plant a cover crop of beans, vetch or bitter blue lupine to correct chalky soil. When dealing with chalky soil, it’s always best to choose a tree that can withstand alkaline conditions. The recommended trees for chalky soils include apple trees, some lollipop topiary, hornbeam, judas tree, grafted cotoneaster trees, mulberry, pear trees and cherry trees.
Peat, sometimes known as turf, is an accumulation of partially decayed vegetation or organic matter. It mainly consists of organic materials and water particles. It retains water but contains fewer nutrients than loamy soils. It is among the top options for the best soil for planting trees since it is among the most fertile. It provides perfect conditions for newly planted trees. It has an acidic pH, so it’s ideal for acid-loving plants, such as blueberries and camellias. Heather, Lantern Trees, Witch Hazel, and Rhododendron do well in well-drained peaty soils.
These are the six main soil types that you need to keep in mind when embarking on a landscape project. Remember it’s best to always opt for peat, loam, or silt soils when planting trees. It’s very important to ensure that your trees are planted in the correct type of soil. Soil is just one of the essential components for planting trees, but ultimately, the quality of your trees will determine the success of your landscape project. One has to ensure that the trees are from a reputable tree nursery and that the trees supplied are in excellent condition. Just Trees is an award-winning tree nursery located in Gauteng and the Western Cape with over 150,000 trees and 58 species suitable for all soil types. Visit www.justtrees.co.za to make your purchase today.