To succeed in planting and then enjoy a well-vegetated terrace or a beautiful garden, you can hardly do without soil. Here are the main characteristics of this growing medium and some advice to follow when buying soil, whether for plants in pots and window boxes, those grown in the ground or for the vegetable garden.
Specificities of the soil
In potting soil,rooting plants is favored just like their growth. This is a amended substratethat is to say of a growing mediumand feed mix essential to plants because it provides them with all the nutrients they need and allows them to assimilate them well. It’s about :
- D’organic elements integrated into a compost such as manure, peat, compost, sphagnum…,
- D’mineral elements such as dolomite, sand, vermiculite or even clay…
There are different potting soils, each suitable in all respects for certain types of plants. Orchids, citrus fruits, vegetable plants, ornamental plants, shrubs, roses, geraniums, lawns, bamboos, cacti and succulents, aquatic plants, young plants, seedlings, vegetable gardens… There are also some for acid soil plants: they are This is heather soil, specific to hydrangeas, rhododendrons, magnolias, camellias…
To resort to soil is offer its plantations optimal conditions provided, however, that they opt for the mixture that suits them best. It is therefore with care that we must choose our soil, whether for plants in pots or those grown in the garden.
Do not confuse compost with potting soil
Neophytes frequently confuse compost and potting soil, yet they are two different products. the compost is an amendment rich in organic matter which results from the decomposition of green waste such as grass clippings, faded flowers, dead leaves… compost must be mixed with garden soil or even in potting soil, but it is not used pure.
Main criteria for choosing a potting soil
The beginner gardener can find himself faced with a difficult dilemma when buying potting soil, as there is so much choice. Fortunately, the main specificities of a growing medium are generally indicated on the bags, and it is important to take note of them. You must at least be able to be informed about the following particularities.
Hydrogen potential or pH
The number 7 indicates a pH neutral. From 0 to 6.9, we are talking aboutacidity and from 7.1 to 14 dalkalinity. This is an extremely important criterion because some plants do not tolerate acidic soils while others absolutely need it to grow in the best conditions.
They are always indicated in the same order, for example 10/20/10. The first corresponds to theNitrogen (N), the second in Phosphorus (P) and the third at Potassium (K). It is absolutely essential to take it into account depending on the plants you want to grow since Nitrogen promotes the growth of foliage, Phosphorus helps plants to take root and Potassium boosts flowering and fruiting.
The ability of the substrate to retain fertilizers
This is the CEC for Cation Exchange Capacity. It must be high enough. It is always indicated for 100 g of soil and is expressed in meq (mg of equivalent).
The soil resistivity rate
For a substrate poor in minerals, the label indicates a high resistivity. This is expressed in Ohm.cm.
The salinity rate of the substrate
Expressed in millisiemens either per meter or per centimeter and sometimes even in microsiemens per meter (mS/m, mS/cm, µS/m), this value varies from 5 to 85. The lowest rates are those of heather land, therefore acid soils, and do not exceed 45 mS/m, while the highest indicate that the soil is translation and rich in minerals.
Water holding capacity
It is expressed in mL/L. The higher this data, the more the soil will retain rain or watering water.
Choose your soil according to its use
An essential element for the success of different crops, the soil must be chosen according to the use for which it is intended. Unless there is a very specific need (for the cultivation of Orchids for example, or cacti), every gardener should have on hand the most common soils in order to benefit from good fruit and vegetable harvests and to have a particularly flowery pleasure garden.
Soil for potted plants
He must be able to retain water well because the substrate dries particularly quickly when it is in a pot. A potting mix is perfect and does not need to be mixed with soil. The plants grow well there and bloom profusely.
For repotting plants intended for growing in window boxeswe recommend the potting soil, ready to use and rich in NPK – in Nitrogen, Phosphorus and Potassium. It is suitable for flowering plants and seedlings purchased from a garden center or from its own seedlings. Have on hand a soil for seedlings and cuttings is essential. It is light, fine, draining, and slightly alkaline with a pH generally between 6.5 and 7.5. It is therefore really essential when sowing, transplanting, cutting or repotting vegetables and flowering plants.
Potted citrus fruits have become essential for balconies and terraces where they can be installed throughout the summer. They need this specific substrate which can be a mixture of sand, perlite, pozzolan, peat. You can add a little compost and non-calcareous soil.
Soil for plants in the ground
The lawn soil is used when you want to re-grass the sparse areas but also when sow grass. Rich in Phosphorus and Potash (P and K), it is light and its grain size is low.
The potting soil for vegetable garden is well supplied with Nitrogen and Potash (N and K) which vegetables and fruits particularly need. As these products are intended for consumption, it is highly preferable to opt for a version adapted to theOrganic Agriculture that is to say that does not contain any chemical fertilizer.
Essential, the universal soil can be used everywhere because it is suitable for all plants: fruit trees, vegetables, ornamental plants in beds, shrubs, trees. However, it is not suitable for sowing, repotting or even growing in pots and planters. Likewise, the horticultural soil is very rich in fertilizer and peat. That is why it is well suited for ornamental garden plants and shrubs.
Other garden soils are more specifically suited to one type of plant. The heathland only suitable for acid-loving plants since it acidifies the soil by reducing its pH. the potting soil for roses limits the risk of soil compaction when planting roses. the special bamboo soil is essential if you want to plant these plants to create a screen for example, because it is extremely draining. This is exactly what is needed for the cultivation of bamboo whose roots are not resistant to excess water.
When buying your soil, if you have the slightest doubt, do not hesitate to seek advice from an expert generally available to customers in garden centres.