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The Ultimate Guide On Cannabis Roots

November 2, 2021

Cannabis roots are (quite literally) the foundation of a strong marijuana crop. Weed takes in the water and nutrients through the underground system, developing flourishing stems, branches, foliage, and colas.

Root health translates into the well-being of the entire pot plant. With that in mind, the importance of keeping it robust, healthy, and stable becomes obvious. 

How can you diagnose and solve a problem you can’t see? Luckily, your marijuana plants display tell-tale signs of root damage on their foliage. You can spot and resolve these issues early on, maintaining the well-being of your entire garden. 

Today, we’re providing the ultimate guide on the marijuana root system

We’ll discuss the importance of roots for cannabis, potential plant health issues that stem from them, and the best ways to solve these. We end with some uses for pot roots once you collect your harvest to avoid anything going to waste.

Cannabis roots in hydroponic system
Cannabis roots in hydroponic system

What are the cannabis roots?

Marijuana roots are the most important part of our favorite green plant. Your weed can persist without branches, foliage, and colas, but the part that grounds and feeds it is essential for survival.

The cannabis plant has three root types:

  • Taproot is the weed root that appears after the cannabis seed sprouts. It’s thin and white, standing as the footing for the other two types later.
  • Fibrous roots are the main parts of the cannabis root system. They grow downward from the stem. 
  • Adventitious roots develop from the sides of the stem as the crop tries to ground itself.

Cannabis root development occurs mainly during the vegetative growth stage. Roots go on to absorb water and nutrients throughout the weed plant life cycle, maintaining consistent expansion.

When your crops enter flowering, marijuana root growth slows down significantly. What’s already there is essential for plant health maintenance and the size of your future harvest. 

Cannabis root structure

Roots in weed develop into a pyramid structure, spreading outward from a singular tip below the main stem. 

The primary root grows downward as deep into the soil as it can reach, and smaller, secondary roots stretch horizontally. After developing, these secondaries produce smaller roots of their own, known as capillaries. 

Weed roots try to spread in all directions, seeking to cover as much of the pot as possible. From their very tips, nutrients and water get absorbed and sent upwards to the entire cannabis plant.

The cannabis root system develops this way in ideal conditions, but imperfect growing environments can alter the progression

If the medium is too dense and compact, the primary root will have difficulty growing secondaries and getting them to pass through the soil. 

As a result, fewer absorbent tips penetrate the medium. The crop takes in reduced amounts of nutrients and moisture, and plant growth slows down.

Main functions of the cannabis roots system

The marijuana root system is more than a food and water straw for your crop. We might not think about it much, but its functions help maintain the health and structural integrity of cannabis plants.

Here’s what the weed root does deep in the soil:

  • It stabilizes the plant. A robust, deep-seated system anchors the crop and maintains its upward stature in the growing medium. Without the support, the plant might tilt to the side when it grows heavy with foliage and colas. 
  • It absorbs nutrients. You provide water and nutes to the soil, but the roots are ultimately responsible for absorption. They send those goodies upward to where your plants need to develop.
  • It stores nutrients. Apart from delivering nutes to your growing plant during vegging, the roots store carbohydrates that will be useful only when it enters the flowering stage.
  • It improves the soil. A healthy arrangement of cannabis roots increases the organic matter accumulation and activity in the medium. That way, the growing environment only gets better with time.

Naturally, these functions all go awry when there’s a weed root health issue. 

Let’s explore what happens when the roots are strong and when they fall ill. We’ll also share some handy tips on troubleshooting issues and maintaining marijuana root wellness throughout the plant life cycle.

Marijuana roots
Marijuana roots

The importance of healthy cannabis roots

Avoiding marijuana root rot and other issues that might occur in the foundations of your crop is essential. If anything happens, proactive action makes or breaks your potential for an abundant harvest.

Sickly cannabis roots are unable to consume water and nutrients at a consistent rate. As a result, you see stunted growth, wilting and yellowing leaves, and smaller harvests. 

Moreover, the structural integrity of your cannabis is at risk due to root issues. Without a robust cannabis root system, the plant can’t stand upright and carry the weight of its leaves and buds. It might tilt to the side or even break if the problem reaches an extreme. 

Finally, unhealthy marijuana roots are more vulnerable to cannabis pests and diseases, and this disorder makes your entire crop defenseless. Bugs, nutrient deficiencies, and mold issues progress more quickly and take a larger toll on your weed garden.

How to keep cannabis roots healthy

Healthy cannabis roots are milky white, relatively dry, and have no particular smell. On the other hand, sick roots are brown or discolored, slimy, and smell of rot. We’ll get into the particular problems in a second, but first, let’s discuss the essential factors that maintain weed root health.

The roots in cannabis have four main requirements to grow hefty, healthy, and happy. They need oxygen, favorable temperatures, ample water sources, and the right cannabis nutrients. Here’s how to provide everything and ensure a foundation for a flourishing garden.


Plants take in a part of the oxygen necessary for growth through the foliage. Another portion of the element comes from cannabis root respiration

The oxygen cannabis absorbs through their lowest portion creates ATP, a molecule responsible for transporting chemical energy throughout the plant structure. If there’s not enough oxygen-rich air to go around, energy can’t move, and your plants starve—even in rich soil.

Providing enough oxygen to weed roots in most cases boils down to proper watering. Drowning prevents air absorption and damages plant health.

Other than good gardening practices, you could skip ceramic and plastic pots and switch them up for something more breathable, such as fabric containers. Perlite and peat moss in your soil mix make the dirt fluffy and light for boosted airflow, too.

Hydro growers need to make sure that their cannabis roots stay in oxygen-rich water. Use air pumps to aerate the medium and promote growth.


Like other parts of your crop, weed plant roots have specific temperature requirements. They develop optimally at around 75 degrees Fahrenheit. The lowest portion of the plant is incapable of self-regulating temperatures, making continual climate control essential.

Regularly measure the warmth of your medium. Use your tools and resources to get them close to the optimal range and avoid damaging hot/cold patches. 

Soil temperature
Kyle Kushman measuring soil temperature


Cannabis roots grow so they can reach more water and nutrient resources. They use that moisture and food to become stronger and more extensive, developing their absorption powers. It’s a continual cycle with growing demands.  

A consistent watering schedule fuels this development.

Gradually increase the amounts of moisture you provide to your weed roots in soil as they 6advance. Don’t focus the watering on the center of your pot, but send some outward to encourage further expansion. 


Phosphorus and potassium are the two elements essential to weed root development. These strengthen the existing structure and encourage new growth.

Fertilize your potting mix with these two nutes before planting to kickstart the process (keep things gentle to avoid seedling toxicity). Providing a balanced NPK solution throughout vegging keeps the ball rolling later on.

Cannabis roots in a pot
Cannabis roots in a pot

What stimulates cannabis root growth?

Robust cannabis roots result in numerous bud sites, higher flower production, large and healthy plants, and generous harvests of supremely fat colas. Apart from following the rules we outlined above, here’s how you can boost root development for a more abundant weed garden:

  • Increase the light exposure. High light conditions promote rooting by increasing CO2 absorption for photosynthesis. Some consumed CO2 goes to the root system, and the more there is, the better they’ll grow.
  • Monitor salt levels. Weed roots find it hard to absorb water and nutrients in high-salt conditions. Flush the soil if it accumulates. 
  • Use lighter potting soil. Add perlite or peat moss to your grow medium to advance irrigation and prevent overwatering. Coco coir is another good option.
  • Use organic fertilizers. Bone meal, flaxseed meal, and manure encourage the growth of natural microbes in the soil, which oxidize it.

Only apply these practices for boosting cannabis root growth when you’re sure the basic conditions are all up to par. All the light and fertilizer in the world can’t do much if the temperature and humidity are off. 

In line with that, let’s discuss the issues you might see when you don’t meet these requirements and ways to solve them.

Cannabis root problems

Maintaining healthy cannabis roots makes the rest of your plant grow fit and strong. On the other hand, when there’s a wellness issue, the whole plant displays symptoms of distress

Here are some common signs that your plant roots might be facing health issues:

  • Curling leaves
  • Foliage discoloration
  • Burnt leaf edges
  • Droopy and lifeless vegetation
  • Stunted growth
  • Rot smell and slimy discharge

Unfortunately, the symptoms of cannabis root problems coincide with other issues your marijuana plant might face. The only real way to know you’re dealing with a root issue is by inspecting this part of your crop and seeing what’s up

Before exploring what causes such imbalances, how they manifest, and what you can do to fix them, hit the play button for a short video on root problems & solutions with Kyle Kushman:

Cannabis root rot

Root rot in marijuana is the number one concern of many novice and expert growers. This sickness occurs when bacteria and fungi grow and feed off the roots in overwatered, hot, and humid soil.

When the cannabis roots rot, your crops start to droop and wilt, displaying sickly yellow foliage. When it comes to the roots themselves, they become brown and develop an unpleasant smell

These can’t absorb nutrients, leading to cannabis deficiencies alongside stunted growth. 

The number one solution here is to transplant the affected plant into fresh, purified soil. Bacterial agents applied directly to the crop also do the trick if the situation gets out of hand. The point is to clean and sterilize everything and remove as much bacteria as possible.

Temperature issues

As we mentioned earlier, cannabis roots aren’t great at regulating their temperatures. It’s on you to do it for them.

The optimal soil temperature range for root development is between 68 and 75 degrees Fahrenheit. Hydroponic setups are ideal at 66 to 77 degrees. Stick a thermometer into your grow medium to determine whether it’s the temps that are giving you headaches.

When the soil or water is too cold, growth slows down, and you see stunted development in your cannabis garden. Hot environments stand as a breeding ground for fungus, mold, and mildew

What can you do to fix this cannabis root problem? Indoors, use lamps and heating systems to maintain optimal temperatures. Outdoors, plant other herbs, or use grass clippings to insulate the soil.

Also, try to aerate your soil. Compact media heat up and cool down more slowly, but they remain that way for a long time, affecting the crop. Loose dirt is easier to regulate.

Temperature for growing weed

Overwatering and underwatering

Marijuana roots need water to survive and thrive. Not any amount of moisture will do, though. Determining the right balance is crucial for well-being. 

Underwatering makes the roots wilt, and overwatering drowns them. Neither is good news for your crops.

Only water your cannabis when the soil dries around an inch below the surface to find that sensitive balance for optimal development. Here are other considerations concerning moisture for weed root health and strength:

  • Water more frequently in media with excellent drainage, such as soilless mixes and sandy soil.
  • Water in moderation if you have a heavy, compact medium such as heavy clay and silt.

Wrong pot sizes

The container is the home of your marijuana plant roots. The underground portion of your crop might struggle to get enough oxygen when it’s too big, while too small pots make them suffocate. Both cannabis root problems result in stunted growth.

The best thing to do here is to transplant your herbs to larger containers once they grow into the current ones. Be careful not to damage the roots, and you’ll see excellent results.

Marijuana root uses you didn’t know yet

Now that you know what weed roots are, what they do, and how to take good care of them, we can drop the serious talk and focus on something a bit more exciting. Did you know that you can use those healthy cannabis roots past the point of your harvest?

What are the marijuana root uses beyond the weed growth cycle? Aren’t they just byproducts of the plant responsible for those gorgeous colas? Not at all. The weed plant is a holistic structure, and all its parts are beneficial for stoners.

Let’s explore how people in the past used cannabis roots and how you can put them to good use yourself. 

The history of cannabis root use

Historical marijuana root uses massively outnumber the potential we’re aware of today. We can learn a lot from these ancient civilizations. 

People have been using cannabis roots for therapeutic purposes and easing pain during medical procedures for thousands of years. 

The earliest texts we have as proof of these uses come from ancient China. These communities used the root paste topically, via juicing and boiling, to soothe various conditions in the body. 

Other ancient cultures note using marijuana roots too. Roman historians wrote about holistic cannabis use in the first century BC, detailing how it alleviates physical discomfort caused by health issues. 

The practice hasn’t died in the relatively new records, either. William Salmon, an English physician, wrote about consuming cannabis roots to ease sciatica symptoms as late as the 18th century.

Both ancient and modern texts have a common theme. Cannabis root uses revolve around medicinal applications to eliminate pain and discomfort from the body. The practice died to an extent due to the criminalization of cannabis in recent years, but some applications persist. 

Modern uses of cannabis roots

Modern uses of roots from weed plants also revolve around their therapeutic properties. 

While limited, evidence exists that cannabis roots contain trace amounts of beneficial cannabinoids, mostly CBD. The concentration differs depending on the strain, plant, and growing style. Moreover, a couple of terpenes make the roots their home.

For these reasons, cannabis root uses in the modern era focus on their potential health benefits

While we still lack definitive answers in this department, anecdotal evidence shows that using cannabis root extract in topical products might relieve physical discomfort caused by muscle and joint issues and injuries. Another option is to boil it into tea and ingest it orally. 

When used in either of these ways, weed root doesn’t induce a high, but it might bring relief from physical discomfort.

Weed root indoors


Before we send you off to cater to your garden or cook up a pot of cannabis root tea, let’s answer some questions we often hear in the community. 

Are cannabis roots healthy to eat?

Yes. You can 100% have yourself a cannabis root snack, and according to anecdotal evidence, enjoy relief in the body for it. Munching on raw roots might not be the most delicious option, though. Instead, boil it into a tea and add herbs and sweeteners.

What nutrients promote root growth?

A hearty serving of phosphorus and potassium is essential for cannabis root growth. Even in vegging, when nitrogen is the number one nute on your focus list, adding a sprinkling of the other two lets the roots catch up with the upper vegetative growth.

What causes short roots in cannabis?

Your cannabis plant might develop short roots due to several environmental reasons. Most commonly, one of the following is the culprit:

  • Compact, packed soil
  • Underwatering
  • Lack of nutrients

You’ll know that you’re dealing with stunted weed roots if one crop isn’t growing at the same rate as the others. 

Healthy Roots Of Marijuana

The roots of a healthy garden

Healthy cannabis roots are essential to your cultivation journey. They ensure that every little weed seed makes the most of its environment and eventually blossoms into a large and fruitful marijuana plant.

Although it’s sometimes hard to notice root issues, prevention is vital. If you suspect you’re facing this issue, be sure to act as soon as possible. Most health issues of weed roots are easy to solve with a watchful eye and enough dedication.

Once you collect your harvest, why not put the health benefits of marijuana roots to the test? Grind them into a balm and nurse that injury with natural medicine in your corner. 

Check our blog for more handy guides and visit the store for your weed seed order. With the quality of our products and your new knowledge, you’ll see your weed garden thrive and bear delicious, potent colas.

About the author: Parker Curtis

Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.

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