Indoor plants grown in regular pots or other similar pots have limited amounts of soil which, moreover, is quickly depleted and due to the frequent watering. The substrate chosen for these plants must meet the needs of each species, particularly in terms of physical attributes, but also of food content and pH.
It is very important that the soil in the pots keeps their porosity and permeability for as long as possible, not too compact easily due to the pressure caused by the repeated watering. A contribution to this end has the drainage layer at the bottom of the pot.
The degree of porosity of the substrate must be very high in azalea, ferns, orchids, epiphytes; normally for violet, begonia, gardenia, terrestrial orchids, Podocarpus; and medium to camellia, hydrangea, poinsettia, and reduced to palm trees, succulent plants, ivy, conifers, hibiscus.
All indoor plants are slightly acidophilic, requiring an acidic soil with a pH between 5-6.5. Such a soil is peat, leaf land, the bark of trees. Peat alone or mixed with other components has the widest use. It keeps its condition for a long time, it is easy, it accumulates large amounts of water. A good peat should not be watered too often, unlike other soils that dry too fast.
Most of the soil for the indoor plants contain at least 1-1/3 peat. In the case of peat-based soil, it is very important not to allow too much dryness between two waterings, a situation where the plant can suffer greatly. Ferrites, orchids, bromelain, azalea, hydrangea, camellia, epiphytic plants are just a few examples that also require substrates.
A smaller group of plants needs heavier, clay-based soil that fixes the nutrients well and also gives the plants without creating the danger of overdosing. Leander, asparagus, Sansevieria grow better in such soil.
Soil mixes are many and different, some of them having equivalent results. On the market, we find a number of soils that meet the needs of different plant categories. Modern techniques include the possibility of growing pot plants in inert substrates (gravel, sand, expanded clay) for rooting and mineral nutrition to feed the plant. The main advantage of this technique is to solve problems related to watering and nutrition. The best results are observed at ficus, philodendron, rushfoil, peace lily.