Soil types
Before you start planting the garden and preparing the soil, it is important to know what type of soil you are dealing with, as well as its properties. This can provide direction on which plants you can choose best and what soil preparation is necessary. Many compositions are possible, but in general we are dealing with the soil types listed below.
- Sandy soil: naturally consists of granular particles that are worn and round or have rough edges. Sandy soil is an airy soil that is easily workable but does not easily retain moisture and nutrients. In addition, the percentage of organic matter is low, so substantial amounts of organic materials (compost, planting soil and/or potting soil) may be applied annually to improve the soil.
- Loamy soil: a naturally perfect gardening soil composed of a mixture of sand and clay particles. This soil type is fertile, moist, but also permeable and is easily cultivated. It needs very little yearly supplementing with organic materials (mulch layer) compared to sandy soil.
- Clay soil: a very fertile soil type, but difficult to cultivate. The soil type retains a lot of moisture, but is difficult to aerate and cultivate. In winter, clay becomes a wet, solid mass and in summer, clay becomes as hard as concrete and will shrink and crack when it dries. Heavy clay soils are best turned over and mixed with extra organic materials in autumn. Leave the dug-up lumps of clay as they are, so they can be broken up by frost.
- Peaty soil: a dark-coloured and acidic type of soil composed largely of organic materials (dead plant residues). This type of soil can absorb large amounts of water, but when it dries out it is very difficult to get the peat (turf) moist again. To improve the structure and make the soil more airy, grit, fine gravel or other gravel-like materials can be added.
- Loess soil: also known as loess, is a type of soil formed by fine particles, mainly dust and silt, deposited by wind. These particles often come from weathered rock. Loess soil has a very fine texture, consisting of particles smaller than sand but larger than clay, giving it a soft texture. Loess is generally fertile soil, rich in minerals and has good water and air permeability. This soil usually has a characteristic light yellow to light brown colour. Although loess soil is fertile, it is also prone to soil erosion because of its fine particles and lack of organic matter. As a result, mixing in compost or potting soil in gardens with loess soil is recommended to increase humus levels.
- Sabulous soil: also known as sandy clay, is a soil type with a moderately coarse texture consisting of sand, clay and silt particles, but the proportion of these particles may vary. This results in different types of sabulous soil. Silt has the characteristic of retaining water well (positive for plant growth) while allowing excess water to drain away to prevent waterlogging. This soil is well-drained, which is essential for healthy root growth, and is easy to cultivate. Adding organic materials can improve soil structure.
Soil type and acidity (also called pH value) affect plant growth. The pH value is expressed on a scale from 0 to 14, with a pH of 7 being neutral. A pH value below 7 is called acidic, above 7 is called basic or alkaline. In general, most garden plants grow best with (ideally) a slightly acidic soil, around pH 6.5. Fortunately, most garden plants are adaptable and will also grow at pH levels that deviate (slightly) from this. However, the ideal acidity is not the same for every garden, as the type of soil plays an important role in this. Lighter sandy soils are most fertile at a pH value between 5.5 and 6.5. Heavier clay soils require a higher pH value, between 6.0 and 7.0.
The pH value affects how nutrient elements behave in the soil. At a certain pH value, some nutrient elements start forming other compounds. As a result, the plant roots may no longer be able to absorb some of the nutrient elements. This may cause deficiency symptoms in the plant, which is also an indication of existing soil conditions. For this reason, some plants depend on a particular soil type/acidity. Acid-loving plants (such as Azalea and Rhododendron) prefer a pH value between 4.5 and 5.5. Lime-loving plants (such as Aucuba and Helleborus) prefer a pH value between 6.5 and 7.5.
If a plant has specific soil requirements, we list them on the corresponding product page on our website.
If a soil is too acidic (locally), i.e. its pH is too low, you can raise the pH value by adding lime.
If a soil is too alkaline (locally), i.e. its pH value is too high, you can lower the pH value (make it more acidic) by spreading peat, for example.
