What is the substrate for indoor plants and what does it consist of? care

Each plant needs a special soil mixture. What exactly it should be is described in detail in individual recommendations for the selected type. But without experience, this is not so easy to figure out. What should be the acidity of the soil for indoor plants? Why is a complex composition and ratio of components important? How does leaf land differ from soddy soil, and can pure peat be used? Answers to these and dozens of other questions will help you understand the substrates and their quality. After all, only the right substrate will satisfy all the requirements of indoor plants.

What is the substrate for indoor plants and what does it consist of?

Different plants – but not so different requirements

Despite the fact that each plant makes its own specific requirements for the soil, its structure, composition, acidity, not all species differ. Without exception, all indoor cultures like:

  • nutritional value of the soil;
  • its water permeability;
  • breathability.

The soil mixtures are light, medium and heavy, but they should be exactly the soil mixtures, and not the soil just dug up in the forest, vegetable garden or taken from under other plants. Even if you prepare the substrate yourself, you need to make a complex soil mixture, achieving the correct texture and characteristics, and combining different components to obtain the perfect soil.

The quality of the substrate is determined by the quality of its individual ingredients.

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The main components of soil mixtures

Tattered land

The basis of most soil mixtures is the surface layer of turfed soil. Depending on the place of harvesting, sod land can be light or heavier, but it is always porous, nutritious, elastic, retaining its properties for many years. The pH values ​​are from 7 to 7,5.

Usually, sod land is obtained from under field turf, harvested in spring or early autumn, cut into squares about 5 cm thick and left to ripen from 8 to 24 months.

For light soils, 20% 0 of soddy soil is sufficient, for medium – about 30%, for heavy soils, up to half of the total composition is replaced.

Leaf Land

Lighter and more humus-rich, nutritious greyish-brown leafy soil is the result of leaf rotting (deciduous humus). In addition to its high nutritional value, it corrects the texture of heavy components and soils. On its basis, substrates are often prepared for primroses, begonias, cyclamens. The pH values ​​of leafy soils are from 5,0 to 6,0.

Deciduous land is harvested in deciduous forests, with ripening up to 2 years. For light soil mixtures, up to 40% of leaf land is used, for medium – 30%, for heavy or rough – only 15%.

Humus earth

Greenhouse or humus soil is an ordinary mature, high-quality humus, which is obtained by overheating manure. It is an organic fertilizer, the most nutritious ingredient in substrates, light and loose. But pH values ​​around 8,0 require careful introduction and calculation of the acceptable amount.

For indoor plants, it is added no more than 15-20%.


Substrates, especially versatile and affordable, often turn out to be pure high-moor peat with baking powder, and they are not suitable for indoor plants. Even such special plants that prefer an acidic soil reaction, such as rhododendrons, begonias, ferns and hydrangeas, love complex-component substrates in which other ingredients are added to peat.

In addition to light high-moor peat, transitional peat can also be used in mixtures. It is an indispensable component for all ornamental deciduous plants. The light, free-flowing texture and brownish tint of peat is easily recognizable. Peat introduces porosity and looseness into substrates. The reaction is pH 3,5-5,5.

Peat substrate should ripen for a long time, up to 3 years. For light soil mixtures, peat is usually not used; it is introduced into medium and heavy soil mixtures in an amount of 10% or more.

Read also our article Peat – what happens and how to use it?

Coniferous land and needles 

Collected in coniferous forests, loose and sour, coniferous soil surprises with its disinfecting properties. It is used only for plants that prefer acidic pH reactions.

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Heather land

Today we are found less and less often, displaced by peat and needles, but very popular in Europe. Harvested in heather thickets and ripening for about 2 years, the heather soil surprises with its lightness and looseness. It is a naturally acidic soil with a pH of 5-5,5. It can be used for rhododendrons, orchids, gloxinia.


Dried sphagnum, which is sold today on the shelves next to perlite, is finally appreciated. From a component obligatory only for epiphytes, it was gradually added not only as a “water retainer” for all moisture-loving crops, but also as a component that gives soils a high-quality looseness and lightness that persists for years. In addition, moss is a kind of disinfectant additive with antibacterial properties.

The sphagnum reaction is about 4,0 pH. It is used finely chopped.

Read also our article Amazing sphagnum moss – how to prepare and use?


An indispensable and irreplaceable improver for water permeability and structure of earth mixtures. For indoor plants, coarse lake or river sand is preferable.

From 10% of sand is added to the substrate (the easier the soil mixture is needed, the greater its share).

Sod land is obtained from under the field sod, cut into squares about 5 cm thickSod land is obtained from under the field sod, cut into squares about 5 cm thick
Moss is a kind of disinfectant additive with antibacterial propertiesMoss is a kind of disinfectant additive with antibacterial properties. Farmer Burea-Uinsurance.com Urban Sprouts
Coniferous soil is used only for plants that prefer acidic pH reactionsConiferous soil is used only for plants that prefer acidic pH reactions. Farmer Burea-Uinsurance.com DominaFiesta

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Loosening and water-retaining additives

To prevent the soil from compaction, it remains breathable even if the plants are transplanted no more than 1 time in 2-3 years, inert substances must be present in it. And if there are several additives, this is only for the best (both in home soil mixtures and in purchased substrate).

Modern loosening components are inert, imparting lightness and porosity, correcting the texture of the substance. The best growers and growers have long preferred:

  • perlite, or rather agroperlite – volcanic rock that has undergone special swelling by high temperatures, during which fractions of up to 5 mm are formed – white-grayish rough baking powder, neutral in PH, sterile, moisture and air-consuming, heat-conducting, remaining in the soil for up to 4 years;
  • expanded clay fine fractions – natural clay material in the form of light granules that are smooth on the outside and porous inside (for mixing into the substrate, a fraction with a diameter of less than 5 mm is used), which promotes better air exchange, improves hygroscopicity, protects roots from decay and overflow;
  • vermiculite – a natural mineral that has acquired its scaly structure and flowability after processing at high temperatures; non-degradable, not entering into chemical reactions, safe, enriching the soil with minerals, moisture-absorbing, preventing soil compaction and its complete drying, often used in hydroponics;
  • coconut fiber – fibers of coconut peel, non-degradable, non-caking, effectively retaining the structure of the soil;
  • ground pumice – an abrasive of a special type of lava, which almost does not absorb moisture and makes the substrate more breathable and lightweight;
  • charcoal – rather, an antiseptic and prophylactic additive that prevents problems with root decay with any overflow, but with a rather coarse texture, it also improves the structure of the soil.
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At home, an acceptable alternative is foam crumbs or special foam balls – sterile, not water-absorbing, neutral.

Increasingly popular are additives that stabilize moisture, absorb water and gradually release it into the substrate. Perlite is the most popular moisture-retaining component (which does not detract from its loosening functions at all), although in many respects it is inferior to vermiculite, which is able to absorb and retain an amount of water 5 times its own volume. But for moisture capacity, you can add sphagnum and hydrogel, which solves the problem of maintaining a constant moisture content of the substrate with irregular care and for particularly capricious plants.

Modern loosening components - inert, giving lightness and porosity, correcting the texture of the substanceModern loosening components – inert substances that impart lightness and porosity, correcting texture

Read also our article Coconut substrate – advantages and disadvantages of using.

Always check acidity

It is very important to check what kind of soil reaction the plant prefers. Even if a specific acceptable pH is not indicated for a species, the designation of whether it needs a neutral, slightly acidic or slightly alkaline substrate is mandatory. In soil with an inappropriate reaction, not a single plant can develop normally.

Most plant species prefer neutral or slightly acidic values ​​- from 5,5 to 6,5 pH. The permissible deviation from this “middle” for special soil mixtures is only 1 point (4,5-7,5 pH).

Highly specialized species substrates are always better

Self-design of substrates requires experience, quality components, access to materials, disinfection before use. Professional soil mixtures save you all the trouble, but it is better to select them, carefully studying the composition and completeness of information about the manufacturer and use. Whenever there is a choice, it is better to prefer substrates for special species or groups of indoor plants, rather than universal soil mixtures.

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In “highly specialized” substrates, the ratio of components is more accurately selected, the content of humus and loosening additives is adjusted, a special texture and water permeability is created, which better meets the individual requirements of plants.

Special substrates are usually called by the type of plant that most vividly represents the group – “Rose”, “Palm”, “Cactus”, “Ficus”, “Begonia”, “Saintpaulia”, “Azalea”, “Orchid” … But they are not suitable for one plant species, but for a whole group that prefers similar soil characteristics. And their list is always indicated on the packaging.

So, palm substrates can be used for all false palms and tubs, for cacti – for any succulents, caudexes, species that prefer a slightly alkaline reaction. Orchid mortars are also suitable for epiphytes, and substrates for rhododendrons are suitable for hydrangeas and gardenias, which prefer acidic highly nutritious soils.

If it was not possible to find a special soil mixture for your species, then it is worth choosing at least a substrate for decorative deciduous or flowering plants.

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Anna Evans

Author ✓ Farmer

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