Are Your Cannabis Roots Healthy? Here’s How To Check
Starting from the moment your cannabis seed finally pops, its root becomes the basis of the young plant’s healthy maturing. As time passes, the root system never loses its importance in terms of the overall health of marijuana plants. Even though we can’t really see what’s happening in the dirt, there are ways to check on the health of your cannabis’ root system – and as soon as it falls victim to a disease or pests, the problem translates into clear signs both below and above the ground’s surface. In this article, we’ll be covering the importance of a healthy root system for cannabis health, as well as the main problems with cannabis roots that could put your harvest in danger –tips on solving each issue included. Let’s dive right in!
Function Of Cannabis Roots
The cornerstone of a healthy cannabis plant is healthy roots. The roots of your marijuana bushes are easily the most vital organ of your plants, as it’s from the roots that cannabis is able to sustain the essential process of photosynthesis. During the process of photosynthesis, carbon dioxide is converted into oxygen and sugars as your plant reacts to sunlight. The roots, in turn, feed on the oxygen from this process to keep your plant alive; oxygen and sugars then react to create ATP (adenosine triphosphate) energy, which provides energy to all living cells. It is this cyclic process in the roots that provides your plant with all the necessary energy to grow. Also, don’t forget that it’s through the root system that cannabis receives the nutrients from the soil, starting from the vital nitrogen, potassium, and phosphorous and finishing with micronutrients like iron, magnesium, zinc, etc.
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How To Check If Your Plant’s Roots Are Alright
The health of your roots ultimately determines the health of the flowers your plant produces. First of all, if you can check the roots of your cannabis plant, pay attention to their color. Healthy cannabis roots are always creamy or white in color, with no sliminess or discoloration.
Moreover, even though cannabis roots are responsible for nutrient intake, nutrient deficiencies are mostly visible in the leaves of the plant, not the roots. For example, nitrogen deficiency can be seen in yellowing and brown spots, phosphorous deficiency causes blue-green, dark purple, or dark copper leaves, potassium deficiency results in dark green leaves and leaf burn, etc. It’s therefore important to keep an eye on your leaves to make sure your roots are healthy and in the perfect condition to absorb all necessary nutrients.
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Before we move on to dissecting common cannabis root problems, just know that it’s always a good idea to prevent most of these problems by using perlite, vermiculite, peat moss, and compost teas to provide nutrients and fluff up the soil, making it easier for natural microbes and critters to move around. Use complete soils to encourage symbiosis between fungus, insects, bacteria, and your plants; these keep the soil loose so that it’s easier for the roots to absorb water and oxygen and grow freely.
Common Root Problems And How To Solve Them
Your cannabis roots can be very easy to manage, but without proper care, they can also be susceptible to a myriad of health problems. Tangled or dead roots, moldy soil, and invasive pests are all common problems to watch out for as you raise your marijuana seedlings to budding stalks. Here are some common issues to be aware of when growing your own cannabis plants.
Tangled Cannabis Roots And “Root-Bound” Cannabis Plants
If your roots become too cramped in their living space, they can tangle up and strangle themselves, depriving themselves of oxygen. This is what’s known as becoming root-bound. Root-bound plants are unable to take in the necessary oxygen for their survival; they can then die off, possibly killing the entire plant. Root-bound plants typically suffer from stem discoloration (reddening), stunted growth in the plant, and slowed growth in flower production. Your roots need plenty of space to grow, so make sure your plant is always in a big enough pot. If your roots are blocking the drainage holes at the bottom of your pot, it’s time to transplant!
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Watering Issues Affecting Cannabis Roots
It’s important to ensure that your cannabis plants are getting the right amount of water. Overwatering your marijuana plants can lead to serious problems in their root network such as root rot, so make sure to let the soil dry completely between waterings. To avoid watering issues, make sure you use pots made of porous material so the soil is able to breathe; pots should also have a proper drainage system. Of course, you should also make sure your plants are in appropriately-sized containers. If your plant needs watering once or more a day, it could be time for a transplant.
Wrong pH Of Your Soil Or Other Growing Media
Cannabis plants need healthy soil to thrive, which also means having the correct pH levels. pH is a measurement of how acidic (0) or basic (14) a substance is. For soil and soil-like systems, the pH should be between 6.0 and 7.0, with 6.3 being the ideal. For hydroponic systems, the range is 5.5 to 6.5, with each of these systems having a different ideal point. If your pH is too acidic or too alkaline, your roots cannot properly intake nutrients, which can cause a plethora of nutrient deficiencies that are detrimental to plant health. So, make sure to always check the pH of both the soil and the water you use for feeding the roots.
Root rot in cannabis is a sickness your plants can get if they become root-bound, are overwatered, or lack sufficient drainage and can therefore no longer take in oxygen. When roots begin to rot, the entire plant becomes at risk of dying. Healthy roots should be visibly white or cream-colored, with no sliminess, darkening, or discoloration. Cannabis root rot is much easier to prevent than it is to treat. To avoid cannabis root rot in the soil, make sure your plants are in proper containers to avoid becoming root-bound. Also ensure that you have healthy soil with a proper network of healthy microbes and bacteria, particularly mycelium, which helps nutrients become more easily available to the roots. Most importantly, don’t overwater your plants, because once rotten, the roots won’t recover – that’s why most growers choose to discard plants infected with root rot completely.
Cannabis Roots Infected By Fungus Gnats And Root Aphids
Fungus gnats are tiny gray or black long-legged flies, usually resembling mosquitoes, which can feed on your plants. Fungus gnats lay eggs in the soil of cannabis plants, the larvae of which are highly intrusive and feed on the roots, organic matter, and healthy fungi in your soil. This can quickly make your weed plant wilt and even die if you don’t act soon enough.
Root aphids, another tiny white bug living in soil, are also a common pest in cannabis plants and are commonly confused with fungus gnats. However, root aphid symptoms cause yellowing, swelling, and hardening of the plant roots, in contrast with the pale foliage and general flimsiness of fungus gnat symptoms.
Insecticides seem to be the best way to rid your roots of both gnats and aphids. In addition, be sure to keep your humidity low and not overwater your plants.
Final Word On The Health Of Cannabis Roots
Everyone expects their cannabis plant to yield bountiful harvests of resinous buds. Unfortunately, this is impossible if cannabis roots aren’t taken good care of. As you’ve learned today, their inspection and the maintenance of good quality soil and other growing media is key if you want to keep marijuana roots, and therefore the whole plant, happy and healthy. Most problems with cannabis roots are much easier to prevent than to actually deal with, so once you plant your seed, don’t forget to come back to this article to check if you’re giving your cannabis roots everything they need to thrive.
How should healthy cannabis roots looks like. Check out our article about some common issues to be aware of when growing your own cannabis plants
Healthy Roots – The Key To Healthy Cannabis Plants
Without a healthy root system, your cannabis plants can never reach their full potential. For a heavy harvest full of spectacular buds, you’ll want to do everything you can to support the health of your plants’ roots. We’ll teach you how to do exactly that, along with showing you how to identify, fix, and prevent a variety of root health issues.
Maintaining healthy roots is the key to growing great cannabis plants.
While they’re hard to see, roots are the heart of your cannabis plant. Responsible for taking up the water, nutrients, and oxygen a plant needs in order to grow, healthy roots are the key to a healthy plant and a quality harvest.
In this article, we take an in-depth look at how to keep your cannabis plant’s roots super healthy, and prevent common root-related issues like root rot, damping-off, overwatering, and more.
What do Healthy Cannabis Roots Look Like?
Healthy cannabis roots are a milky white colour, and don’t have a particular smell. If you’re growing in pots, your roots should be growing throughout your medium but should never be wrapped completely around the sides of a pot.
If you’ve ever seen a plant with sick roots, you’ll know exactly how your roots shouldn’t look: brown discolouration, a strong smell, and slime around your plants are telltale signs of root rot or other root problems.
How to Keep Cannabis Roots Healthy
The roots of any plant, including cannabis, need 3 basic components to grow properly; oxygen, the right temperatures, and nutrients. Here’s how to give your plants everything they need to develop healthy, happy roots:
To the surprise of many rookie growers, plants actually take up oxygen by respiring through their roots. This process is essential for the creation of ATP (Adenosine triphosphate), a molecule that helps transport chemical energy throughout a plant. Without enough oxygen, plants can’t move energy throughout their organism and essentially starve.
If you’re growing in soil, a big part of providing a plant’s roots with enough oxygen is proper watering. Overwatering essentially drowns your plant’s roots, which not only starves it of energy but also creates a breeding ground for pathogens. Hence, we always recommend letting your plant’s soil dry out between waterings. Other tips to help improve oxygen flow to a plant’s roots when growing in soil include:
- Growing in fabric or smart pots. Unlike ceramic or plastic pots, fabric and smart pots are made out of breathable material that helps air get to all parts of a plant’s roots, not just the topsoil. The RQS Fabric Pots, for example, are specifically designed to maximize oxygen flow to your plant’s roots.
- Use perlite, vermiculite, or peat moss in your soil mix. All of these materials help keep soil light and fluffy, improving airflow around a plant’s roots.
- Use compost and complete soils made with organic materials that help promote the life of beneficial fungi, bacteria, insects, and microbes to help keep your soil loose and promote the growth of big, healthy root networks.
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If you’re growing in a hydroponic system, you’ll need to make sure your plant’s roots are constantly immersed in oxygen-rich water. One of the most common ways hydroponic growers increase the oxygen content of their reservoirs is by using air pumps or stones constantly aerate the water. Not only does this supercharge the growth of your plants but it also helps prevent your water from going stagnant and housing nasty pathogens.
Cannabis roots are happiest at around 24°C, respiring and growing most during the night. If you’re growing in soil, there are a couple of things you can do to keep the temperatures around your plants’ roots consistent. These include:
- Placing an intake fan under your canopy and an exhaust above your canopy to promote a healthy flow of air around your indoor grow room. A lack of air circulation can lead to hot spots in your grow room that might drive up the temperatures around your plants’ roots.
- Using thermometers to constantly measure the temperatures in your grow space.
- If you’re growing outdoors, you can use crops (like clover) or mulch and hay to cover your topsoil and insulate a plant’s roots. This works particularly well in areas with significant temperature drops.
In hydroponic systems, you’ll want to keep the temperature of your water between 19 and 25°C. At these temperatures, dissolved oxygen levels in the water are at their highest, leading to better nutrient uptake and faster growth. There are a couple of things you can do to keep the temperature of your reservoir at its best:
- Paint your reservoir container white. White paint reflects light and heat, helping to keep your reservoir cool.
- Regularly adding ice or cool water to your reservoir to cool it down.
- Investing in a chiller. While hydroponic chiller systems are expensive, they are the most reliable option for larger setups.
Roots grow in constant search of water and nutrients. As a plant develops stronger roots and grows bigger, you’ll want to ensure you water it correctly to continue fuelling its growth.
For soil growers, this means gradually increasing the amount of water you give your plants and your watering radius. Whenever you water your plants, you’ll want to apply some water just outside the radius of their roots. This will help guide your roots further out towards the edges of your pot to seek out more space and available nutrients.
In hydroponic setups, you’ll need to walk the fine line between keeping your plants emerged in water so their roots don’t dry out while also providing them with enough air to respire.
While we often think of nutrients as the fuel to power our plant’s vegetative growth and bloom, they are equally important for the development of healthy roots.
Phosphorus and potassium are two of the key nutrients for root development, helping strengthen existing roots while also encouraging your plants to grow new ones. Nitrogen, on the other hand, encourages leggy green growth; if you notice that your plants are developing a lot of foliage while their roots lag behind, it may help to boost the phosphorus levels in your fertilizer.
If you’re growing in soil, we recommend working some phosphorus and potassium into your soil before planting. Bone meal and rock phosphate, for example, are great sources of phosphorus, while wood ashes, kelp, and greensand are all-natural sources of potassium that you can work into your soil to help your plants develop healthy roots early on.
In a hydroponic setup, you can use phosphorus and potassium-rich fertilizers early on in your grow to help your plants develop strong roots faster. Both in soil and hydro, vitamin b1, indole-3-butyric acid, and 1-Naphthylacetic acid can also promote rooting.
Troubleshooting Cannabis Root Problems
Below you’ll find a comprehensive summary of the most common cannabis roots problems and how to identify and treat them.
Overwatering and underwatering are very common problems among rookie cannabis gardeners. Luckily, both are easy issues to fix given you detect them early.
The two telltale signs of overwatering and underwatering include drooping and wilting. Look at a plant’s soil, however, and you’ll get a clearer picture of what you’re doing wrong: if the soil is completely dry, you’re underwatering; if the soil has been wet for days and refuses to try, you’re overwatering.
If you’re underwatering your cannabis plants, you’ll want to start watering them more frequently. While every grower’s watering schedule will be different, the basic rule of thumbs is to only water your plants once their soil has dried out.
If your plants have been overwatered, on the other hand, you’ll want to wait for their soil to dry out completely before you water them again. Consider giving them less water each time to avoid overwatering their roots.
2. Fungus Gnats
Fungus gnats are small fly-like pests that love to lay their eggs in moist potting soil. And while they are often thought of as a minor pest, they can have a pretty devastating effect on your plants if you let their numbers get big enough.
You’ll usually find fungus gnats floating around your indoor plants. Adult gnats will lay their eggs on moist topsoil. Once they hatch, the larvae of the gnats burrow into the soil to feed off its organic matter. Once mature, the adult gnats emerge from the soil, and the process repeats.
While adult gnats don’t damage plants, their larvae may feed off your plant’s roots, causing symptoms such as drooping and wilting. Adult gnats can also spread the spores of fungi (such as pythium) as they lay their eggs, which is why it’s important you identify a gnat infestation quickly.
There are 3 main parts to dealing with fungus gnats:
- Killing adult gnats. The easiest way to do this is by using fly traps.
- Killing the larvae. First, treat any infested plants with microbial insecticides like bacillus thuringiensis. Next, let your dry out before watering it with a mix of 1 part hydrogen peroxide and 4 parts water (this will kill off the gnat larvae without damaging your plants). Reapply this solution once a week until the adult gnats no longer reappear in your grow room or garden.
- Preventing a future infestation. Proper watering and mosquito traps or dunks can help prevent fungus gnats from laying their eggs in your garden.
3. Excessive Nutrient Feed (Nutrient Burn)
While fertilizers can help your plants develop grow faster and develop bigger buds, excessive feeding can cause some serious damage to a plant’s roots, stunting its growth and causing it stress that may drastically impact the quality and size of your yields.
Nutrient burn can have several causes. Inexperienced growers, for example, sometimes get tricked into thinking that the more nutrients they give their plants the better. Among more experienced growers, however, nutrient burn can still occur, especially as a result of pH imbalances that cause unexpected nutrient buildup in a plant’s medium, exposing its roots to high concentrations of fertilizer.
Regardless of its underlying causes, nutrient burn causes the same telltale symptoms, including:
- Unnatural, deep green leaf discolouration.
- Upward-bending fan leaves.
- Yellow-brown, dry leaf tips.
Dealing with nutrient burn involves:
- Using pH and EC checks to identify what’s causing a plant’s nutrient burn.
- Flushing the plant’s roots with pH.adjusted water for 1 week.
- Slowly dialling your nutrients back in while checking your pH and EC to ensure your plants are able to absorb their nutrients properly.
- Using the right dose of nutrients.
4. Root Rot
Root rot, as the name suggests, causes sick, rotting roots. It’s usually caused by a buildup of bad bacteria and fungi (like fusarium and pythium) that thrive in overwatered soil or stagnant water.
Root rot causes plants to droop or wilt and develop yellow, sickly foliage. Unfortunately, these symptoms are pretty common across the board of cannabis pests and diseases, and you’ll only know for sure that a plant has root rot by looking at its roots.
Rotting roots are slimy, wet, and brown in colour and sometimes have a distinctly “rotten” smell. In hydroponic setups, you might also find algae growing around a plant’s rotting roots.
As the bacteria and fungi that cause root rot attack a plant’s roots, they interfere with its ability to absorb nutrients and water. This can sometimes cause signs of a nutrient deficiency, such as yellowing leaves, stunted growth, discoloured stems, and more.
If you’re dealing with root rot in soil-grown plants, you’ll want to transplant the affected plant into fresh soil in a sterilized container. Before doing the transplant, also mix a beneficial bacterial agent (like Bacillus amyloliquefaciens or Mycorrhizae) into your new soil or apply it directly to the plant’s roots.
Once you’ve treated and transplanted your affected plants, monitor their health and repeat the treatment with Bacillus or Mycorrhizae if need be.
If you’re a hydro grower battling a case of root rot, you’ll want to clean and sterilize your entire system, including everything from your pots to your pumps. Next, you’ll want to fill your reservoir with clean, pH-regulated water and add Hydroguard or another bacterial agent to it. Before placing your plants back into their pots and into your hydro system, try gently washing their roots under cold tap water, remaining extra careful not to break any of them.
Now, monitor your plants’ health and repeat the bacteria treatment if need be.
5. Root Bound
Plants become root bound when they run out space in their containers. As the roots outgrow their container in the search for more space, they can become a tangled mess. Over time, root-bound plants will stop growing and can develop nutrient deficiencies as their tangled roots struggle to take up water/nutrients and respire properly.
Some commons signs of a rootbound cannabis plant include:
- Quick-drying soil. If you find you’re watering a plant every 1 or 2 days, that’s a good sign that it needs more water than its container can hold.
- Nutrient deficiencies. Rootbound plants struggle to take up nutrients and, over time, will show signs of nutrient deficiencies like yellowing leaves.
- Lots of growth in the same container. If a healthy plant has been growing in the same small-to-medium container for months, chances are it could be starting to become rootbound.
- Tipping. If a plant is too tall or wide for its container, it will become unsteady and may tip or fall over regularly. This is a telltale sign that it’s outgrown its container and may start becoming rootbound.
To prevent a plant from becoming root bound, you’ll want to transplant it to a bigger pot before it outgrows the one it is in. Ideally, you’ll want to transplant a plant once its roots have reached the edges of its pot and before they start wrapping around the borders of its container in search of more space.
- Canopy size. When a plant’s leaves cover the circumference of its pot, this is a good sign that it needs transplanting.
- Root development. Look at a plant’s roots through the drainage holes; if they’ve reached the bottom of their pot, the plant needs transplanting.
- Grow time. As you get more experienced, you’ll know when it’s time to transplant a plant-based on how long it has been growing for. You may also opt to move your plants to bigger pots during the last 2 weeks of veg to accommodate for their stretching once they enter the bloom phase.
If you’ve let your plants get rootbound by accident, you’ll need to loosen their roots before transplanting. To do this, remove as much soil from the plants’ roots as possible, then use sharp, sterilized clippers to prune and loosen the root ball.
Finally, move the plant into a bigger pot and let it veg for at least a week to recover from the stress of the transplant.
6. Poor Root Structure
Cannabis roots develop a pyramid-like structure; a plant’s taproot grows vertically down into its substrate, while its offshoots and their capillaries tend to spread out horizontally. Unfortunately, some plants struggle to develop a strong, structurally sound root system, which can affect their ability to take up nutrients and water or respire, resulting in stunted, unhealthy growth and a poor harvest.
One of the main functions of roots is to firmly anchor a plant in the ground. Plants with poorly developed root systems may struggle to stay upright, especially once their branches grow heavy with flowers. Because the roots are also responsible for nutrient and water uptake, a plant with poorly developed roots may also show signs of over or underwatering, slow or stunted growth, and nutrient deficiencies, which may affect the size of its yields.
To help your plants develop healthy root systems, it’s important you support their root development as early as possible. One way to do this is by using rooting hormones when germinating your seeds or taking clones. Another, more holistic approach, is to plant your cannabis plants in a medium with a rich microbial life.
Microorganisms like Trichoderma, Endomycorrhiza, and Rhizobacteria, for example, develop healthy symbiotic relationships with a plant’s roots, helping them absorb more nutrients to fuel faster, healthier growth while simultaneously protecting them from pathogens (like pythium and fusarium). Growing in an organic super soil is one of the best ways to expose your plant’s roots to a rich mix of beneficial microorganisms.
If you’re not growing in soil, you can use bacterial and fungal agents which can be applied either to your system’s reservoir, the medium you’re growing in, or directly to your plants’ roots.
7. Hot or Cold Root Zone
Temperature is one of the biggest factors influencing the growth of a plant’s roots. Cannabis specifically likes daytime temperatures of between 16 – 30°C. Temperatures outside this range slow the growth of the plant and may affect the potency and aroma of its flowers. Temperatures below 13°C force the plant into a mild shock.
Cold or hot temperatures can shock a plant’s roots, causing drooping, wilting, stunted growth, yellowing leaves or other forms of discolouration, and changes in water consumption. Heat also attracts bugs into the growing area and can create a breeding ground for pathogens, which can attack your plant’s roots and create a wide array of other problems.
Temperature issues around a plant’s roots may quickly affect a plant’s drinking and nutrient uptake, as well as nutrient deficiencies or burn.
The best offence against cannabis root temperature issues is a good defence. Get into the habit of regularly measuring the temperatures in your grow room as well as your medium (be it soil or water).
A great way to cool down roots is by using fans beneath your canopy. Outdoors, you can also use a layer of rocks or mulch or a tops soil crop (like clover) to insulate your roots and stop temperature fluctuations.
If your root zone temperatures are too cool, on the other hand, try redirecting your fans away from your plant’s soil, using a humidifier to gently lift the temperatures beneath your canopy, and mulch to insulate the root zone.
In hydroponics, maintaining root zone temperatures is a little simpler; as long as your reservoir temperatures are within the right range (we recommend keeping them between 18 – 25°C), you shouldn’t have any issues.
Fusarium is a dreaded fungus capable of destroying entire cannabis crops. It’s one of the most common perpetrators behind root rot and its spores have the ability to lay dormant for years, making it virtually impossible to detect until it’s already attacking your plants.
Fusarium attacks a plant’s roots, interrupting its ability to take up water and nutrients. When it strikes, fusarium causes drooping and wilting. You may also notice an affected plant’s soil staying wet for days as it stops taking up water. In some cases, a fusarium infection can kill off a plant in a matter of days.
Unfortunately, there is no cure for fusarium. Once it is in your garden, you should focus on stopping it’s spread by culling any affected plants and sterilizing your grow room.
Pythium is another killer dreaded by cannabis growers the world over. It is a form of parasitic algae and another principal cause of root rot (especially in hydro). While it can attack plants at any stage during their life cycle, young seedlings are most at risk of this deadly algae.
Below the ground, pythium causes a smelly, brown, gooey mass around a plant’s roots. If you’re growing in hydro, you’ll be at an advantage of spotting these symptoms. The above-ground symptoms of a pythium infection include everything from drooping and wilting to signs of nutrient issues or light burn, making it particularly hard to properly diagnose a pythium infection when growing in soil.
Pythium can sometimes be treated using specialized root rot agents. However, it is important to realize that these treatments are expensive and don’t always guarantee results. If you’re dealing with a pythium infection in your seedlings, it is usually best to pull the plug on your grow, sterilize all your equipment, and start fresh rather than embark on the uphill battle to see your plants through to a pretty mediocre harvest.
10. Damping Off
Damping-off is one of the most common problems facing growers. It is caused by pythium, botrytis, and fusarium, and only affects seedlings and clones.
Damping-off causes cannabis seedlings to topple over and wilt. It can happen within hours; you might wake up to perfectly healthy seedlings that, by the time you check on them again in the evening, are laying face down in the dirt.
There is no treating damping off. Once a seedling or cutting has toppled over, there’s nothing you can do to save it.
If one of your seedlings starts damping off, the best you can do is remove it from your grow space as quickly as possible to stop the spread of the algae. Some growers like to sprinkle a few drops of hydrogen peroxide on the affected seedling to kill the fungus and help prevent its spread.
The Importance of Creating a Healthy Root Zone for Cannabis
The roots of a cannabis plant are responsible for taking up the nutrients, water, and oxygen your plants need in order to grow. To help your plants grow as healthy as possible and produce the best possible flowers, it’s vital you help each plant develop a strong root network during early on to fuel its production of buds later on.
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Roots are the heart of your cannabis plant. If you want a great harvestm you'll want to do everything you can to keep them healthy.