cannabis root growth

Cannabis Roots – Ultimate Grow Guide

Roots are the most important part of almost all plants. By absorbing water and nutrients they provide the necessary function for a plant to grow. Unhealthy roots will only result in underwhelming harvests, meaning they need to be looked after properly.

First time growers often underestimate the importance of taking good care of the roots. Cannabis roots that are happy and healthy are essential for vigorous growth and big yields. This article shows you why they play such a big role in the life of a cannabis plant.

What are Roots?

The root is the first growth after germination starts. There are 3 types of roots which can be found in the vast majority of plants, including cannabis.

The tap root is the main root which emerges from a seed after breaking its husk. It is the central pillar from which other roots grow. Offshoots from the taproot are called fibrous roots, which develop smaller root hairs (capillaries) that are used for the absorption of water and nutrients.

Adventitious roots can also develop in cannabis plants. These are roots which grow from the main stem as an attempt for the plant to root itself. Cannabis plants are perfect for cloning because of their ability to grow adventitious roots.

Root Structure

The way roots branch underground is very similar to the plant growth pattern above ground. Unless they are clones, cannabis plants always have the same structural root growth – tap root, fibrous roots and capillaries.

Different containers affect the overall structure of roots as they will grow where they need to to find water/nutrients. This is why a lot of growers choose to transplant, because it allows roots to spread themselves more efficiently within the growing medium of the final container.

The density and structure of the growing medium will also determine how roots expand within their container. Roots will find the easiest way to reach the needed resources but if they have to use too much energy pushing through growing medium to find them, it is likely they will suffer.

The Function of Roots

Without the roots a plant would not grow. They are the foundation from which a cannabis plant supports and grows itself. This is why roots need to be taken care of with the utmost care. The aim should be to give roots the conditions they need to function to their full potential.

There are 2 main functions of the root system:

  • Transfer of water and essential minerals – capillaries growing from the fibrous roots are working hard to transfer everything the plant requires for explosive growth.
  • Support – roots form the base structure which holds a plant up. A well developed root system means a cannabis plant will have enough anchorage to support the production of heavy buds.

Root Growth

Roots grow mostly in the vegetative part of a cannabis plant’s life so that by the time they reach flowering there are plenty for the easy uptake and transfer of nutrients to the flowers.

Giving cannabis plants a proper wet and dry cycle throughout their life means healthy root growth. The way to do this is by providing roots with good amounts of oxygen in between watering. Oxygenated roots is key to achieving big plants with high yields.

Root boosting supplements can also be used in the early stages of plant growth to maximise root development and efficiency.

  • Germination – Once a seed recognises it has water surrounding it the tap root will sprout and grow as it finds a substrate to make a home in. Roots like temperatures of around 20 – 24°C.
  • Seedling – Plants start to develop secondary roots (fibrous) as the plant finds support within the growing medium. Small root hairs shoot off and begin their search for nutrients.
  • Vegetative – By this stage there should be lots of fibrous roots and capillaries. There is an increase in water/nutrient absorption, accelerating plant growth. The plant is well established within the growing medium as it prepares to flower.
  • Flowering – Root growth slows down massively. From this point the roots are focusing on delivering water and nutrients to the flowers. Roots still need taking care of so be careful not to overwater during this phase.

Tip: Roots will not search for water without a dry cycle, resulting in small plants with low yields.

NuggetPawn from GrowDiaries has taken good care of his plant’s roots from the beginning.


Flushing simply requires you to feed your plants with only water, usually for 2 – 3 weeks before harvesting. This will help to flush out any excess nutrients still surrounding the root structure, leaving you with plants that taste and smell much better.

Well flushed cannabis buds have cleaner, smoother flavour and aren’t so harsh when smoked.

Eventually, towards the end of the flowering period, plants start drinking less and their leaves turn yellow. These are good signs that the roots are slowing their function as plants use up the remaining store of nutrients. If plants have dark green leaves when flowering finishes it could mean there is still too much mineral content.

Feeding Schedule

Flush time

Yellowing Leaves

Too early – plant may use its resources before buds have finished developing

Early – leaves yellow faster as plant begins to use stored nutrients

On time – foliage should still be mostly green and then turn yellow once flushing begins

Late – yellowing arrives later. Nutrient-free plants are not normally completely green when harvesting

Roots Problems

If you do not notice problems underground, signs of unhealthy roots will begin to show through the leaves. Growing in soil means roots are not visible, making it harder to monitor their health. Although roots should not be exposed to light, hydroponics systems give the possibility to check roots more easily.

Problems often start at the roots so check your plants regularly for any unusual changes. If you notice slow growth, deficiencies, drooping or curled leaves, there could be an issue with the roots.

Plants that are still small enough can be checked by turning the plant upside down and carefully removing the pot as if you were transplating.

Overwatering – Roots become deprived of oxygen, growth slows and there is a risk of them rotting.

Solution: Use an airstone in your pot/reservoir to prevent algae or rot. Infections can be treated with hydrogen peroxide but make sure you check the strength first and dilute accordingly.

Underwatering – If roots dry out too much it can seriously stunt or kill a plant. Once roots dry out it is very hard to save them. Underwatered plants may survive but yields might be affected drastically.

Solution: Get into the habit of watering less, but more frequently. Irrigation can be set up on a timer although you should be regularly monitoring incase of failure.

Over fertilizing – Nutrient solutions can be too strong for roots and cause ‘root burn’, limiting growth and absorption of minerals.

Solution: Flush overfertilized plants with water. Once plants have stabilized and started showing new growth you can begin feeding again. Start with small quantities of nutrients and work your way up. Never use more than the recommended amount.


We can understand a lot through the appearance of a cannabis plant, but what is happening below the ground is equally as important. Neglecting your roots will only lead to disappointing harvests or failed grows, so pay attention to your watering schedule and give them plenty of oxygen.

Now you’ve learnt about the importance of roots and their function, you can use this knowledge to grow even better plants! Leave your thoughts and tips below, we’d love to hear from you.

External References

Chemical and Biological Studies of Cannabis sativa Roots. Medical Cannabis and Cannabinoids. – Elhendawy, Mostafa A & Wanas, Amira & Radwan, Mohamed & Azzaz, Nabil & Toson, Elshahat & Elsohly, Mahmoud. (2018)

Everything you need to know about cannabis roots. Learn all about root structure, functions and growth in this ultimate grow guide.

Accelerating Cannabis Root Growth With Beneficial Microbes

Here’s how you can stimulate expansive root growth in your cannabis plants — which means bigger crops — by utilizing the power of beneficial microbes.

As cannabis growers, it’s easy to get so focused on our crop’s vegetation and flower growth that we lose sight of what we can’t see: Our plants’ roots. But the fact is, what we see above the soil is a reflection of what’s going on beneath it — and that means if you can grow bigger, stronger roots, your plants will grow bigger, healthier, more potent fruits. That’s why we’re discussing why our crop’s root structures are so important, what stimulates root growth, and how we can improve and accelerate plant root growth using beneficial microorganisms.

Roots 101: Root Development In Cannabis

First, we need to take a moment to emphasize how important your crop’s root structures are.

Roots are the foundation from which your cannabis grows. The job of the roots is to absorb the water and nutrients in the root-zone environment, then transport those essential vitamins and nutrients up through the plant via the root system. Your plants’ leaves use these nutrients in the process of photosynthesis.

But your crop’s roots aren’t a one-way system. Some of the adenosine triphosphate ( ATP) energy produced during photosynthesis is sent back down into the roots to be stored for later use — like during the bloom phase, when your plants receive less light.

There are several factors that play into root growth, including temperature, moisture levels and the availability of oxygen. That’s right — your crop’s roots need oxygen, even though the upper portion of the plant utilizes carbon dioxide. This is why it’s critical to have proper airflow into the root zone.

Why Root Growth Is Crucial For Your Cannabis

Many growers inadvertently waste money and resources by feeding their plants more nutrients and supplements than their roots can absorb. The fact is, once your roots have reached maximum storage capacity, any additional nutrients you supply them will simply go to waste in the root zone.

However, by increasing the size of your root mass, you’ll increase your plants’ capacity for nutrient storage and energy production. In other words, bigger, more expansive roots mean bigger, more productive cannabis.

What Stimulates Cannabis Root Growth?

Now that we understand the importance of developing the biggest root systems possible, let’s explore how we can go about stimulating plant root growth.

Hydroponic growing offers several benefits over growing in soil. But there are also some downsides to this style of growing. One major disadvantage is missing out on all the beneficial microbes that abound in rich, healthy soil.

In fertile soil — the kind that has a strong, earthy smell — there are billions of microorganisms. These microbes benefit plants by working symbiotically with them to create bigger, healthier, more expansive roots — which in turn leads to bigger plants that thrive.

But what exactly are these microbes? And just how do they benefit your cannabis and help expand root mass?

How Beneficial Microbes Benefit Your Cannabis Crop

Two types of beneficial microbes live in healthy soil: Fungi and bacteria. These microorganisms work with the roots in different ways to promote root growth and enhance overall plant function, health and size.

Certain bacteria will colonize in different areas within the root structure, thereby expanding overall root mass and nutrient absorption capacity.

Other bacterial and fungal strains fight off bad bacteria and pathogens, defending your plants against toxins and disease , while still other strains can help plants recover from a harmful infestation.

Another way in which these microorganisms benefit your grow is by breaking down nutrients and micronutrients and making them more readily available to your plants through the production of chelators. Plus, there are several strains of bacteria that supply your plants with growth and bloom cofactors to further increase branching, budding and flowering sites.

Additionally, beneficial microbes can increase the production of essential oils within your plants.

Promoting Cannabis Root Growth With Microbial Nutrients

Just because you grow hydroponically, doesn’t mean you can’t benefit from microorganisms. You simply need to add a high-quality microbial fertilizer into your crop’s feeding regimen.

As with all hydroponic gardening nutrient and supplement formulations, not all root development fertilizers and microbial fertilizers are created equal. So, how do you know what to look for in a quality microbial supplement ?

First, you want to research the type of microbes that are beneficial for the specific cannabis crops you grow. There are hundreds of strains and species of beneficial fungi and bacteria — but you need the right strains and species in the right ratios in order to reap their benefits.

Second, you’ll want to look into how the microbes were produced. Some nutrient and microbial supplement manufacturers breed multiple strains of bacteria and fungi all together in a big vat — but this results in an unstable microbial population that can harm your cannabis rather than help it.

You’ll also want to ensure the supplement you choose has the largest number of live microbes possible. Beneficial bacteria and fungi are only beneficial if they’re alive — which means they have to be packaged in a specific manner.

For example, even though they can coexist in a root-zone environment, some beneficial microbial strains are incompatible when bottled together in a concentrated solution, which means the manufacturer must know which strains and species are incompatible to bottle them separately so that the microbial populations are preserved within the packaging.

Advanced Nutrients Voodoo Juice: The Beneficial Microbe Supplement To Stimulate Plant Root Growth

Fortunately, there’s a beneficial microbial supplement that meets all the criteria listed above: Advanced Nutrients Voodoo Juice.

Voodoo Juice is an ultra-premium, proprietary blend of beneficial bacteria proven to increase root mass and crop yield. The four strains of bacteria present in Voodoo Juice work synergistically to:

  • Develop a system of fine cannabis root hairs that increase water and nutrient absorption.
  • Colonize plants’ vascular systems, enhancing nutrient transport into and within the crop.
  • Produce plant growth factors that boost growth.
  • Make nutrients and phosphates more soluble and available to your plants.

Voodoo Juice can be applied anytime during your crop’s life cycle, but it’s especially productive during the first two weeks of both grow and bloom phases. This way, your plants’ root zones get the full benefits of these four rhizobacteria.

Grow Bigger, Healthier Roots And Reap The Benefits At Harvest

Remember this: The crops you see growing out of the medium reflects their roots. Harness the power of Voodoo Juice and cultivate bigger, more expansive roots — and your yields will follow suit.

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Here’s how you can stimulate expansive root growth in your cannabis plants — which means bigger crops — by utilizing the power of beneficial microbes.