marijuana root ball long or wide

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.


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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 th …

Actual Root growth


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Jonathan Ott


Blaze , this is exactly what I thought . Remember years ago we were all taught that the roots system of trees looked like mirror images of the tree growth above ground ? Since then it has been discovered that is wrong , and their growth is exactly like you described finding with cannabis .
So actually for growing indoors with clones , a wide shallow pot would be more favorable then a deep narrow one . So those who grow indoors in beds actually have the right idea .

Truth Hurts
Bill Bloome

So what your saying is that the girls don’t care how deep it goes, just how wide it is??

Truth Hurts

simple thing to dois look at your plant no older than 4 weeks flower, the width of the plant is exactly how wide the roots has travelled. its called the plants “drip line”.
It is the same for indoors, the wider the buckets the better the yields.


dig a serious hole outdoors, and fill it with some serious goodies. 3 x 3 x 3 minimum.

at the end of the season, you won’t be able to pull it up.

as long as there is favorable medium for the roots to grow into, they will keep going.

i am talking about plants with a stalk the size of your arm. no tiny roots on those girls.

Truth Hurts

And old thread but I was thinking about this the other day. Since I work around a lot of clay type soils. I learned some interesting things here, I didn’t think that the roots grow out more than down. I thought they just push their way equally but run into competition growing latterly. I don’t think wide pots are a wise idea indoors, since square is the way to go and that width is usually about plant numbers. but some grow bushes indoors with large containers.

I have these holes outside, that look so stable from the clay type soil. It’s made me think about what it is going to be like, digging out root mass. I haven’t put enough effort in out door experiments to really see fact verses fiction. The current holes should be perfect to see where the roots get to.

The holes are about as deep as my fist to my elbow, and about as wide in a circle. Large enough to put both feet in and have it at the very base of my knees, some holes are larger. I’m glad I read about the ‘drip zone’ so I know how far to place top dressings. That is very helpful since top dressings also help keep away tender weeds from invading.

I think I will get a root ball down to the bottom of the hole and some past that, but it gets pretty thick with clay type soil. it’s not pure clay, but it’s not draining well. If your roots aren’t growing deep, it may not be draining well down there. that is a thought.

Tobor the 8th Man

I have had 10 ft plus plants in cornfields that had the roots go down over 5 feet. Most of my guerilla grows along stream banks the tap root can go down very deep to the water table which can be 5 and 6 feet when on a high bank.

You have to make the plant adapt to the ground when you transplant it into the hole. Encourage it to have deep roots so it doesn’t need to be watered and can thrive when there is no rain. When you dig a wide hole and not very deep and then you water it frequently to get it established the roots will grow outward because that is where all their water is. They don’t have to go looking. I used to use a painstaking method where I didn’t disturb the roots at all when I transplanted outside. I have since fine tuned my method.

I like my seedlings to be at least 8 weeks old and as tall as I can get them. I actually don’t mind stretchy plants if it happens but for the most part I have very healthy plants that are hopefully 15 to 20 inches above the soil surface in the pot.

I dig my hole 3 feet deep and pour in a gallon of water and veg ferts and let it soak in. While it soaks I mix some dolomite lime in the soil I took out of the hole. I add a cup of pre soak water gel to the bottom of the hole and then fill in the hole with a foot of loose soil. Moisten that soil. Now you have a 2 foot hole that is presoak and tilled for a foot down. Take the plant out of its pot (make sure you watered it some first) and loosen up the bottom of the root ball gently. Put it down in the bottom of the hole and take note how much your plant sticks out the top of the hole. Ideally you only want 2 or 3 leaf sets above ground level and ideally you will have 4 or 5 sets or more of leaves below ground level. Pinch off all the leaves and branches that will be underground. Now fill in the hole with the rest of the soil you had removed. If you have shorter plants just fill in with more soil so that only 2 or 3 leaf sets are above ground. If your seedlings or clones have alternating leaves one leaf counts. Now water the whole area with another gallon of ferted water. Put up your chicken wire fence (or you wasted your time) and sprinkle some slug stuff around the base.

Now the roots are deep and they have water down there. They will grow towards it while the plant gets established. Everywhere you removed leaves or branches will shoot roots out from those spots. You will end up with roots all along the 2 foot hole and then deeper roots from the original rootball that are now 3 feet down at least through the foot of loose soil. Don’t baby it for the first month. You won’t have to. This plant will be able to thrive during the driest conditions especially if you mulch it good with leaves or branches.

This is why deep holes are better IMHO for a GUERILLA GROW. You don’t have to go back and tend the plants until harvest if you want to go total guerilla. If you want to do minimal care that ensures a good harvest use this plan. First visit is to plant in late May early June, 2nd visit July 1 to clear weeds and give another shot of veg ferts, 3rd visit August 1 to clear weeds, cut off lower branches and trim out small center branches to prevent mold and give veg and flower ferts, 4th visit Sept 1 to tie, fix, remove flowering branches and give flowering ferts, 5th visit Oct 5-15 harvest for me as I use 8-10 week strains. If you have longer strains you will need another visit.

Most of my guerilla grows in the wild never gets visited between the time I plant and the time I harvest. No trails=no rippers. I usually have one spot I baby in a cornfield and visit whenever I want and maybe a wild spot just for fun. But I do it knowing full well a trail could give the spot away.

For those of you who grow outdoors have you ever removed a plant or dug down to see how deep and wide unrestricted roots go ? I am curious about the tap…