Di: Dra. Weed - Anita Bucci Coltivazione

In previous articles, we saw the importance of soil for the proper development of our plants. Today we will talk a little about the composition that our substrate must have in order to be able to make a good cannabis crop in pots.

The substrate 

The substrate is a homogeneous mixture of compost, pearlite, peat, sand, bark and hummus, among others. There are fertilised substrates. Personally, I recycle and recompose my substrate every season after harvest.


If you are going to buy fertilised substrate, always make sure you know if that product was kept in the shade and if it was well aired.

For the preparation of a good substrate we must know the ingredients that we are using:


They come from a fermentation and high humidity; they have a high carbon composition. Black peat is not recommended for garden because it has excess mineral salts.


The blond peat is the most used in the garden because it retains liquid and helps to aerate other types of soil. Crop professionals choose it for it stability since it is easy to supply the plants with the fertilizer in the irrigations.

The peats have the ability to retain up to 10 times their weight in water (beware of over-watering).


The sands are mixed in the substrate to improve the drainage of the plants, oxygenation, sanitation, aeration, plant stability and the best rooting. 


It is always advisable to place 3/4 of soil and 1/4 of sand so that it has the ideal properties.


It is a volcanic rock that contains between 2% and 5% of water. It is silicate rock; therefore, it also provides silicon. The pH of the pearlite is neutral, improves drainage, it is very light and economical. It retains moisture but to a lesser degree than vermiculite.



It is a mineral formed by magnesium or iron silicates and it contains some water.

It is able to retain moisture and nutrients from our plants. It can contain magnesium calcium potassium and harmonium, very necessary in the crop. Its pH is also neutral and is totally inert. It promotes aeration and absorbs large amounts of water


Earthworm humus

It is basically the excrement of the worm after having eaten the organic waste found in the soil. This product provides numerous benefits for our plants. Improves soil quality; helps the absorption of nutrients, thanks to fulvic and humic acids, and facilitates rooting. It is also totally organic.


Coconut fibre

Coconut fibre is obtained from the coconut fruit fibres. It also has great capacity for water retention and aeration. The pH is around 5.5 to 6.5 approximately, making it suitable for most plants. In addition, it retains and releases nutrients. It is an organic and sustainable product.


Mycorrhizal fungi, trichoderma and algae extract

As we saw in previous articles, these fungi protect the roots, and facilitate the assimilation of nutrients quickly. The algae act as bio-stimulants, helping the plant in its growth and vigour.


Rice husk

The rice husk improves the physical characteristics of the soil and organic fertilizers, facilitating aeration, moisture absorption and nutrient filtration.



Dolomite is a versatile mineral that is commonly known under the term magnesium limestone. It is both a calcium carbonate and magnesium; its composition has various materials, such as manganese or iron. It is frequently used by gardeners to stabilize and reduce soil acidity.


Ash and chalkcoal

In general, wood ash contains a lot of calcium and potassium and, also, silica, magnesium, phosphorus, some sulfur and very little nitrogen.


Chalkcoal is chemically inert; it has a high absorption and the property of retaining nitrogen from the air and converting it into an accessible form for plants. It functions as a catalyst for the biosphere vital activity of the humus layer.

  • It significantly improves the quality of soils, their structure, richness in nutrients and, as a result, the yield of crops increases;
  • It delays the release of volatile carbon into the environment;
  • It is strong antibacterial and antiparasitic remedy for the plants;
  • It removes residual toxic chemicals from the soil;
  • It has positive effect on the development of beneficial microorganisms that increase soil fertility;
  • It acts as soil ripper;
  • It increases the access of oxygen to the plant roots;
  • It Increases the permeability of the soil, retains moisture;
  • It prevents the washing-out of soil nutrients, especially in fields with intensive farming during the active irrigation.

With all the ingredients studied, we can make our substrate. The proportions that I will dictate here are for a basic growth substrate. Remember to make a rich substrate from the beginning, this will directly favor production!

PEAT 50%
SAND 3/4 soil 1/4 of sand 
ASH / CHARCOAL A handful 


I hope you found this article to be useful and you can enjoy a good cultivation of cannabis!

Kannabia Seeds Company sells to its customers a product collection, a souvenir. We cannot and we shall not give growing advice since our product is not intended for this purpose.

Kannabia accept no responsibility for any illegal use made by third parties of information published. The cultivation of cannabis for personal consumption is an activity subject to legal restrictions that vary from state to state. We recommend consultation of the legislation in force in your country of residence to avoid participation in any illegal activity.