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7 Tips for Understanding the Root Zone of the Cannabis Plant

When growing cannabis, it is generally understood that the final root zone is a reflection of the success of the plant itself.

Big roots means big fruits and when you see how commercial farming utilises hydroponic systems to increase final weight as well as logistics, you will understand that the root zone is the difference in a high quality crop of knockout dank, or a deficient plant that has lost all vigour and life.

Most growers will see a compact root bound plant and think that this is the root zone at maximum capacity, when in fact the science behind the root zone suggests otherwise.

Different Types Of Roots

There are 3 different parts of the root structure and the first is the tap root. This is the tail that will emerge from a germinating seed, which will then act like an anchor and push downwards in the grow medium.

From this main root emerges other root hairs each with a different role. The tap root will also determine the amount of growth hormone, auxin, produced, which is the hormone responsible for apical dominance. Depending on how big your pot is will also determine the amount of fibrous roots that will be produced from the tap root.

The second part of a root structure are the fibrous roots. These are the ones that emerge directly out of the side of the tap root and will work themselves outwards in a network of uniform root hairs. They will grow horizontally in the grow medium forming a net. However, due to the depth of some of the fibrous roots, they can only absorb moisture and nutrients from the upper parts of the grow medium. These are the ones that will search the medium and absorb what moisture and available nutrients are present.

The third type of roots are known as ‘adventitious’ roots which will actually grow from part of the plant above the grow medium. You may have come across a clone dipped in rooting hormone, and notice above the rooting cube there are white hairy roots forming from the side of the stems. Also you may find in mother rooms with high humidity, white stubs forming up the lowest few inches of the stem.

One trick that many growers actually do when transplanting to a larger pot, is to raise the current rooted plant a few inches higher out of the new grow medium, so there is an area that is exposed to air. This technique promotes thick wooden adventitious roots similar to the roots of a tree.

Root Pruning

Pruning is perhaps something you have only practised with the plants, however pruning your roots has the exact same benefits. At microscopic levels, these tiny root hairs are in darkness under certain moist conditions. When these root hairs come into contact with air, they naturally prune themselves and split in two. Topping cannabis plants allows a cultivator to grow multiple tops and manipulate the canopy to their will. If you can do the same with the root zone then you can form a network of roots that are constantly pruning themselves and growing in a way that is the most advantageous to the roots zone and the plant.

If you have ever grown in fabric pots, large net pots or pots with air chambers built around the sides, you will know that roots will grow sideways towards the exposed parts of the pots. Then once the root has split in two at the contact of air, it will turn back on itself and begin to search the grow medium and extend the mass of roots. Ultimately this scenario will happen over and over again until there’s a spider web formation of fibrous roots.

A great way to grow with pruned roots is to use fabric pots, or even make your own plastic pots with air holes 5mm wide. You will notice when you re-pot and check the roots, there will be an abundance of roots that have grown sideways and not root bound. When a plant has become root bound, this is only restricting the formation of the roots to the size of the pot which has no free air flow.

A great tip here is if you have a root ball which has become very dense and root bound, simply take a knife and cut the base of the roots into 4 and then begin to break the roots apart by hand. This will allow the roots which have been cut away to form new roots and then freely grow into a new direction in the new grow medium.


When new roots form and some fragile roots hairs become damaged and die, they can become harmful pathogenic threats which can cause a total infection of new root growth. This can most frequently be seen in deep water culture when a fresh bright white root zone, becomes a brown stained slimy dense colony of root rot.

Enzymes play a vital role in recycling and digesting old root matter. Not only does this eliminate collateral damage to any other plant growing in the same water source or part of the same system, it feeds the plants also. Once inside the grow medium and as long as a growing substrate is present, enzymes will need the right amount of moisture, P.H and heat to activate and survive.

Beneficial Bacteria

If you are reading this and are new to growing, you may not be familiar with the subculture of growing with beneficial bacteria. There are many forms of beneficial bacteria and fungi that will form a symbiotic relationship with the root zone. The bacteria which hosts itself in the root zone and is the benevolent type is called anaerobic bacteria, which means with the aid of oxygen it will metabolise and break down organic matter and work in harmony with the plant.

The principal behind growing with microbes is that the microbes will break down their own independent food source, which will be carbon based fibres and fructose molecules. Once the microbes have converted their food into necessary micro and trace elements for the plant, the delivery and efficiency of the plants ability to feed as it wants is now at full potential.

Growing Mediums

How your growing medium acts as a long term base for the root zone can determine many factors. Some plant deficiencies can be caused due to the root zone not functioning correctly due to cold temperatures and water logged conditions. Phosphorus for example will become deficient in a root zone which has cold roots. This is just one example of how important the functionality is of the plants metabolism and development and also how the grow medium can have an adverse effect on the root zone.

A great tip is to use a grow medium which has a high capacity of air when dry, as well as an excellent water retention when wet. Recommended is a mix of coco and perlite. Then, you can add humates such as worm casting and bat guano, which already has a huge count of microbes and beneficial bacteria within. Feeding molasses will allow your roots to enjoy the liquid carbon sugars which they will convert into energy for the plant.

P.H And E.C

Standing for potential hydrogen and electrical conductivity, these two go hand in hand. As the grow medium and nutrients all have their own P.H and E.C, supplying a constant nutrient solution that is in balance with micro and macro nutrients will allow the root zone to function with full integrity.

Adding organic matter to the grow medium will cause a change in P.H and E.C, the same way that rain water can cause minerals to be leached from the soil. It is also worth considering that oxygen will  increase P.H, so when growing in a system that requires an air pump, be vigilant of how much your P.H will increase as this will have an equal effect on the E.C of the nutrient solution.

Flushing The Roots

In order to get the smoothest flavours possible and an ash that burns a soft white, you need to fully remove all of the salts that are in in the grow medium. When you see plants turning yellow, purple, red, orange and sometimes even a black colour, this is the plant indicating extreme deficiencies. Using enzymes will speed up the flushing process and clean the roots completely, ensuring you have those cannabis cup winning flavours.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.


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