The soil, its manufacture
The soil serves as a growing medium. It is therefore obtained by mixing different materials. These materials are then sieved to obtain a more or less fine soil depending on the types of soil.
Here are the different materials that can be found in the composition of the various potting soils.
- Peat are the most used materials. These are decomposed plants, such as sphagnum moss.
- Coconut fiber is obtained from the fibrous shell of the coconut.
- Vegetable compost is mainly used for potting soil used in organic farming.
- Pozzolana is a volcanic rock which has important advantages for culture.
- Maritime pine bark is crushed and then composted for use.
- Heather land comes from the subsoil of forests. It is an acid earth.
- Perlite is also a volcanic rock.
Depending on the quality of soil desired, one or more of these materials are mixed and sieved to obtain a material that will be adapted to the different needs.
Do potting soil and soil need to be mixed?
As a general rule, it is recommended to mix the potting soil with garden soil, because, by its nature, it makes it possible to obtain a substrate whose consistency prevents too rapid drying. In this way, plants installed in pots or in planters, such as annuals, for example, will be less quickly confronted with thirst.
For container culture, the amount of soil to add to the potting soil will depend on the quality of this first. You can either mix it by thirds or by half. Similarly, for plantings in the ground, you can add potting soil that you mix with the soil. You will find that your plants are growing better. The explanation is that the roots benefit from a more flexible substrate in which they can find their way more easily, which greatly promotes their growth.
The composition of a good soil
The composition of the soil differs depending on the plantations for which they are intended. It is therefore important to choose a suitable soil. In general, the bag of potting soil lists the main components, but also the qualities of the substrate contained in it. Depending on these criteria, we obtain potting soil of very different quality with a very specific vocation. It is therefore necessary to be able to understand the composition for an informed choice of your soil.
The PH
The PH allows to be informed about the acidity of the substrate. It is between 5.8 and 7. This is important because, depending on the plants, the acidity requirements differ. For example, heather prefers land with a lower PH, while hollyhocks prefer a higher PH.
Water retention capacity
The substrate must be able to store water to allow plants to draw it as and when they need it. It is expressed as a percentage, the rate must be at least 50%.
Fertilizer
Soils that have been enriched with fertilizers are frequently found in the trade. In this case, an NPK distribution expressed in brackets appears on the packaging of the potting soil.
Organic matter content
To benefit from a good quality soil, favor those with a high organic matter content. It must be at least 50%.
Nitrogen (N)
Nitrogen promotes the development of your plant. Among other things, it will allow the plant to develop its foliage. It therefore plays an important role especially during the period of plant growth, that is to say in spring. If nitrogen turns out to be insufficient, you may find that the stems of your plant are showing signs of weakening and the shoots are rather stunted.
Phosphate (P)
Phosphate is also necessary for your plants to grow healthy. It helps strengthen the roots.
Potassium (K)
Potassium is essential for flowering. It can be for shrubs, perennials, annuals, etc. The flowers will be more beautiful and more abundant. Therefore, for strawberries, tomatoes, etc., you will obtain more fruiting, which allows you to enjoy a better harvest. Potash influences not only the size of flowers and fruits, but also their colors.
Should I use potting soil?
Despite its virtues, the soil should not be used systematically. And for good reason, it represents a cost which, when buying a quality soil, can quickly reach new heights. Plus, let’s be honest, it’s not always a very green solution. This is why it is preferable to use it only when it proves to be necessary, whether it is for the repotting houseplants or for outdoor pots or tubs. Its use will also be expedient for the realization of your seedlings or your cuttings. Here’s how to use it:
- For the outdoor crops, it is possible to mix it with the soil of the garden at the rate of 30 to 50% potting soil.
- For the indoor plants, it is possible to use pure potting soil or add up to 20% garden soil so that the mixture retains all its flexibility.
- For the citrus, vegetables, potted fruit trees, you can opt for a soil for citrus fruits or a soil for vegetable garden usable in organic farming.
- However, for orchids, better do not use soil from the garden, but only a soil specially adapted to them.