Maintaining a healthy root system is essential to getting a good yield and lots of sticky buds.
Roots are the lifeline of all plants, absorbing oxygen water and nutrients and sending these vital elements up through the plant, to interact with sunlight and be transformed into sugars and energy for growth.
A damaged or restricted rootball will be limited in it’s capacity to perform this task well.
Or from the opposite perspective,

your cannabis plants can only grow and produce as much as the root system will allow them to
Because roots grow within soil, it’s often the case of “out of sight, out of mind “, and many growers overlook their importance.
In fact, bigger roots, bigger yields!


... Roots are the major source of absorption of water and minerals.
... Roots take in nutrients necessary for good growth and are able to store those not used immediately .
... The root system anchors plant to the growing medium and stabilizes it .
... Roots synthesize cytokin, the hormone controlling vegetative growth but also apical dominance.
... Roots can establish a symbiosis with mycorrhiza, fungi which trade accelerated absorption of nutrients for constant access to carbohydrates.


The first root to develop is called the “radical”.
It exists within the seed in an embryonic form and is the first thing to emerge on germination.
Once the seed senses that conditions are right for germination, the radical root grows, pushes its way through the seed case and into the soil, seeking water to send up to the developing leaves in order to start the process of photosynthesis.

In some strains the radical root evolves into a tap root, a singular major root several feet in length, from which all other roots branch off.

In contrast, other strains the radical root will die back while the plant is quite young and the root system develops as a dense mass of fine roots (an adventitious fibrous root system) from the base of the stem.

Certainly, vertical roots stabilize and support the Cannabis plant, but their main function is to seek water and nutrients further away in the soil.

But it is the network of lateral hair roots which branch horizontally from the vertical roots which will absorb the most nutrients and water.

A healthy roots ball will be white, and consist of a mesh of fine horizontal roots growing from many vertical roots.

Damaged roots are restricted as to the amounts of nutrients and water they are able to absorb and transfer upwards through the plant.

So how can you tell if the cause of Ill-health is situated under ground?


. Burnt leaf edges
. Yellowing leaves
. Pinkish leaves
. Brown spots
. Falling leaves
. Curled leaves
. slow growth

Mixed signs of nutrient problems which don’t respond to adjustments in feeding
reduction in water uptake

(Mature plants) droopy stems or leaves. If the roots are unable to absorb sufficient water to meet the plant’s needs your Cannabis will be under watered irrespective of how much water you give it.

(Young plants) Leaves appear plump but droop downwards.
At first glance over watering can be confused with under watering: in both cases the leaves wilt. But in the case of over watering it is that the leaf cells have received water to full capacity, and are weighted down.
The chances are though that the leaf cells won’t be able to absorb sufficient water from an over watered soil to reoxygenate the medium.
Oxygen is necessary for many root processes including nutrient uptake.

Over watering is a particular problem with young plants and small, developing root systems.
Cannabis plants with roots sitting in consistently wet soil are likely to develop root rot, be weak and prone to pathogenic infections.


As a result, these are all signals which only become apparent once root damage is established and is effecting the upper plant.
Experienced and sensitive cannabis growers can spot problems before this.
Once they have double checked that the environmentals are within the right ranges, good growers will look at issues with the roots as most probable cause of an unhappy looking plant.
The first thing to do to confirm this diagnosis is to flood the pot with plain pHd water in order to look at the run off.
Rotting roots will cause this to be smelly and often discolored.
A nutrient buildup will show in the ph and ec reading.

If you’re still not sure, carefully remove the plant from it’s pot and examine the root system itself.
Bear in mind that any disturbance of the roots will cause a delay in plant development whilst the rootstock heals itself.

Tap the outer sides of the pot to loosen the rootball, turn the pot upside down whilst supporting the plant between a V of the fingers of your left hand.
Use your right hand to tap the base of the pot and gently shake the contents out.
A healthy root system should be white, with a network of fine roots growing from the main ones.


. Over fertilization.
Also known as “nute burn”.
Too strong or too frequent a dosage of nutrients will shrivel roots.
Don’t make the mistake of thinking that extra food will be turned into bigger buds, as anything beyond the plant’s natural capacity to absorb is more likely to cause damage.
The end result will be less nutrients are taken up and plant growth is reduced.
Over watering.

. Too much water in the soil pushes out oxygen and the roots “drown”.
This most often happens when young seedlings are kept in pots much larger than the size of the rootball.
A newly developing root system can only absorb water in its immediate vicinity: but novice growers will enthusiastically water the entire pot.
Best practice is to start off in small (3”/10cm) pots and pot on as the plant grows.

. Insect attack.
Root aphids and fungus gnats live in cannabis root balls, damaging them. disease.
There are a number of diseases which can effect the root system but the most common is Pythium.
Pythium thrives in warm water and over watered soil.
Be ruthless if any plants show symptoms and remove them from your grow room before the disease spreads.

. Restricted pot size.
A too-small pot restricts root growth and limits the overall growth of your cannabis plant.
Signs that your cannabis plants are root bound include frequent wilting, stunted growth, yellowing leaves, new leaves are smaller, and there are signs of nutrient deficiencies.

. Temperature:
roots are much more sensitive to temperature extremes than the actual plant.
Cannabis can cope with an occasional drop or rise but if the root system experiences either cold or heat there will be a negative impact on overall plant development.
Poor drainage, either from the pot itself or due to a claggy medium.
Roots sit in wet soil with low oxygen levels.

. Incorrect Ph of the water.
Ph determines what elements can be absorbed by the roots. Read more about the importance of ph here.


Identify the probable cause.
Luckily most issues become obvious once you have diagnosed root development disorder.

. Tackle the cause:
maintain a healthy happy temperature (read why grow room temps are important)
avoid under/over watering (the wet/dry cycle)

.Pest control root infestation
Treat insect attacks with the appropriate pesticides.
An effective way of dealing with gnats is to hang yellow sticky traps.
These are harmless to your cannabis plants but will attract and kill flying adult insects such as gnats, white fly and aphids. At around $12 for 20 strips, we suggest using them in an indoor grow room as a preventative measure.

.keep plants in the appropriate pot size
maintain a good climate control in your grow room.
If growing outside insulate pots at night in cold weather and raise off the ground in hot sun (this enables air to circulate and prevents baking the root ball.

.check the temperature of the water ESPECIALLY in a hydroponic set up.
Warm water holds less oxygen and diseases flourish


. Give young plants the best start:
Cannabis is most vulnerable during the first three weeks.
Seedlings and clones are dependent upon the developing root system to send water up through the stem for use in photosynthesis as the plants use light to convert carbon dioxide and water into the sugars necessary for growth.
Promoting vigorous root development at this stage results in larger plants which are healthier, more resistant to pests and diseases, and which will produce bigger yields.

. Avoid the temptation of feeding young plants.
Use a neutral soil, specially designed for seedlings.
When you do start to add feeds to the water, start off at 1/80 of standard veg stage strength.

. Avoid overwatering.


. Use a cannabis root stimulator..

This may seem contradictory to the statement above, but whilst we advise against giving young marijuana plants nutrients, you will find that using a root stimulator for cannabis seedlings has huge impact on the plant’s potential.

. What are root stimulators?

Cannabis root stimulators contain macronutrients which enable seedlings to develop an enhanced primary root system capable of supporting vigorous vegetative growth and excellent nutrient absorption.
Giving seedlings even a diluted vegetative feed risks more damage than it benefits.
A seedling/ clone root stimulator reduces the problem of over feeding and also yellowing leaves with reduced photosynthesis.
Other stimulators are designed to promote vigorous growth throughout the life cycle of the plant.
Every brand of cannabis nutrients is likely to provide a root stimulator. Key factors to look for are:

. Multiple vitamins
. Enhance disease resistance
. natural ingredients
. Suitable for use beyond seedling stage
. easily absorbed