Before planting, many gardeners wonder why some plants thrive while others wither. The answer often lies beneath their feet: the nature of the soil. Each plot of land has its own characteristics, and understanding them is the key to achieving sustainable landscaping.
But how can you tell if your soil is clayey, sandy, chalky, or acidic? What simple tests can you do yourself? And when should you seek the advice of a professional?
Why analyse your soil?
An adapted soil allows:
- to avoid costly failures (poorly adapted plants that do not survive),
- to reduce watering and maintenance,
- to strengthen the overall health of the garden,
- to make sustainable and consistent planting choices.
Knowing the composition of your soil is a bit like having the identity card of your garden.
Simple methods at home
1. Observe the texture
Take a handful of slightly damp soil:
- Clayey: sticky, malleable, easily forms a compact ball.
- Sandy: grainy, crumbles quickly, does not stick to the fingers.
- Limy: soft to the touch, crumbles but retains some cohesion.
2. The sausage test
Roll a small cylinder of clay between your fingers:
- If it stretches without breaking → clay soil.
- If it breaks immediately → sandy soil.
- If it holds a bit but ends up breaking → silty soil.
3. The colour and the smell
- A dark and soft soil indicates a good humus content.
- A clear and dry land often reflects an organic poverty.
- A pleasant smell of woodland is a sign of a living soil.
4. The drainage test
Dig a hole 30 cm deep, fill it with water.
- If the water disappears in less than an hour → draining soil (sandy, chalky).
- If the water stagnates for several hours → heavy and compact soil (clayey).
Measure the pH of the soil
The pH is essential for knowing which plants will thrive in your garden.
- Acid (<6): ideal for rhododendrons, hydrangeas, Japanese maples.
- Neutral (6-7): versatile, suitable for the majority of plants.
- Basic / chalky (>7): favourable to lilacs, buddleias, lavenders.
You can buy test strips or a pH probe at a garden centre.
Observe the spontaneous vegetation
Nature is an excellent indicator:
- Presence of ferns, heathers, mosses → acidic soil.
- Abundance of thistles or dandelions → nitrogen-rich soil.
- Numerous poppies and cornflowers → light, draining soil, often calcareous.
When to call on a professional?
If you wish to create a large project (terrace, lawn, flower beds, hedges…), a landscape gardener can carry out a more detailed analysis with:
- soil sampling,
- study of the structure,
- tailored recommendations for the selection of plants and amendments.
This expertise allows for anticipating problems and laying the right foundations from the outset.
In summary
Analysing your soil is not a step reserved for experts: with a few simple actions, you can already understand the main points. Knowing whether your land is acidic, clayey, or chalky will help you make smart and sustainable choices for your plantings.