Cannabis roots. Healthy cannabis roots means healthy cannabis plants.
One of the more overlooked aspects of home growing is the subject of cannabis root structure and development. Usually cultivation discussions focus more on topics such as maximising bud development, optimising overall yield, finding the best nutrient blend and maximising THC levels/terpene profile.
Cannabis roots, their health and development, are a hugely important part of the cannabis plant. A plant with a poorly formed rootball will struggle to absorb the minerals and nutrients required to support a large, healthy plant with potent buds. It doesn’t matter how good the genetics are, without the foundation of a healthy cannabis root system you will have substandard results.
Read on to find out more about optimising plant health via a large and healthy cannabis root system. Discover more about the medical preparations and extractions which can be made from the cannabis roots themselves.
Cannabis roots. Key to healthy cannabis plant growth and development
Anyone that has grown their own feminised cannabis seeds and harvested their plant will have seen the marijuana root structure after harvest. Most of the time the grower simply discards the weed roots and focusses on the bud trimming. But the cannabis root system is a vital part of your growing. In general terms, the bigger and healthier the marijuana root system, the larger the final plant that can be supported.
If you have ever seen a large cannabis plant wilting outdoors in midsummer in a small container it’s usually because the root system simply can’t bring enough water from the restricted volume of grow medium. But, if you placed the same plant in the ground in a larger volume of quality, moist soil it would be able to expand the size of its cannabis root system and access more moisture for the plant.
Cannabis roots. What does root-bound mean?
A cannabis plant in a small container will often have roots that are tangled and knotted in a small ball. This is a result of growing in a restricted space. Even re-planting it in a larger container may not solve the issue if the root ball is too tightly bound.
Sometimes it is possible to gently untangle the root system and tease the roots apart, though prevention is always better than cure.
Try to grow your cannabis plants in the largest containers which are convenient and practical for your situation. Many growers will periodically transplant their cannabis plants every few weeks in gradually larger containers, often adding mycorrhiza and other beneficial bacteria to the new soil to encourage the cannabis roots to grow out into their new territory. Beneficial soil organisms and nutrition is a great way to grow healthy marijuana seedlings with rapid root growth.
Tips to improve the health of cannabis root systems
Cannabis roots love moist, nutritious grow mediums to grow in. You can use soil, coco fibre, glass wool or other grow mediums. Cannabis roots will grow healthily in them all if a few basic rules are observed.
Cannabis roots love to be oxygenated. These days many people that grow their own cannabis seeds use airpots. These are typically black plastic grow containers with hundreds of air-holes punched around the side. Not only do these ensure great levels of root oxygenation, but the dimpled air holes prevent roots circling wastefully around the base and sides of the container. Instead, the roots are diverted back into the centre of the container where they can fully utilise all the available nutrition. Many modern growers of autoflowering cannabis seeds get great results with airpots in the 15-20 litre range. Those that grow feminised cannabis seeds with long vegetative periods may even wish to select containers in the 30-50 litre size range to really allow a huge cannabis root system to develop.
BioTabs sell a great range of natural, organic products which stimulate healthy root growth such as Bactrex and Mycotrex and are recommended to growers looking to improve the quality of the cannabis root zone. Cannabis roots shouldn't be viewed just as a simple system to get moisture and nutrition from the soil to the plants. Cannabis roots will often grow best when they are in a healthy symbiotic relationship with their grow medium and have beneficial bacteria to help them. Of course, they need oxygen, the right pH and a nutrient concentration which is neither too weak nor too strong.
Cannabis roots. Use of fabric grow containers and tensiometers to grow marijuana roots faster
Fabric grow containers are another great way to ensure an oxygenated root ball. The porous fabric material allows air to pass through to the root ball easily. Moisture can also escape quicker from a root zone grown in a fabric container. Use of these containers may therefore necessitate increased water/feed usage. If you are a real pro and want the best possible plant health and root health then consider using a tensiometer. These are small, simple devices to monitor the moisture content of your grow medium. Many growers feel that a tensiometer is a good way to avoid over-watering your plants. When the cannabis root zone is waterlogged and denied oxygen, the roots will rot. Overwatered cannabis recovery takes time, prevention is better than cure. The reason cannabis roots don't rot in e.g. a deep water culture hydro system is because the roots are bathed in a stream of oxygen rich bubbles.
Cannabis roots and pH. Does pH affect cannabis roots?
Many people that grow in e.g. coco fibre or hydroponic systems use a pH of around 5.8 for their water and nutrient solutions. The pH is a measure of acidity, with pH 7.0 being neutral. However, cannabis roots are not able to absorb minerals correctly if the pH is wrong. Even if the relevant minerals are present, the roots simply can’t absorb them if the pH is wrong. That’s why so many serious growers regularly check and calibrate their pH meters and always have a spare one just in case the main pH meter breaks down or starts producing erroneous results.
Those that grow their cannabis seeds in soil will not usually need to worry about pH since soil itself is a natural pH buffer. For those growing organically there is even less worry about pH levels, it is definitely the easiest growing method to keep your roots healthy and thriving.
Cannabis root discolouration. What do brown cannabis roots mean?
Cannabis roots are normally a healthy white colour. Growers that use hydroponic systems will regularly check and change their nutrient solution. This is essential to maintain the right nutrient levels and ensure a fresh solution free of bacterial growth. If ever you smell a rotten aroma from your hydro system, it’s usually a sign of bacterial contamination of the feed solution. This can lead to serious root problems. The roots won't grow in bad conditions and will often turn increasingly brown as the root health deteriorates.
Cannabis roots and temperature
Cannabis roots enjoy a steady temperature of around 22ºC. If the roots get too cold the plant growth is stunted. Likewise, if the roots get too hot, growth will cease, and plant health will quickly deteriorate. Many people that grow their feminised cannabis seeds outdoors in containers in their patio/back yard will be familiar with the challenges. In very cold weather, a small outdoor plant container offers the plant roots very little buffer against the cold. Also, in hot climates and bright sunshine, a small black plastic plant container can raise the temperature of the root ball to dangerous levels. That’s why many outdoor cannabis growers use white containers (which don't get as hot) or they use large plant containers to give a greater buffering effect against cold/heat.
Planting your cannabis plants directly into the ground with good quality moist soil is the best way to protect the roots from temperature extremes and allow the most extensive root development.
However, many growers who like growing in containers point out that they can be moved in the event of unwelcome visitors or extreme weather. This Dutch Passion blog provides useful information about the cannabis root system.
Common questions about cannabis roots
Below are some of the more frequent questions asked by cannabis growers. This Dutch Passion blog about common cannabis plant problems may also be useful reading.
Q. Which insects can attack the cannabis root system?
A. Root aphids, fungus gnats and other pests can live in the roots and damage them. Your garden centre should have the materials (diatomaceous earth, root treatments solutions) which can help.
Q. Can the cannabis root system become diseased?
A. Yes, Pythium and a variety of related waterborne root diseases can slowly destroy the roots. Prevention is the best form of cure, keep the roots oxygenated and ruthlessly remove affected plants from your grow room.
Q. Marijuana roots would normally rot if left in water - why?
A. Cannabis roots need air as well as water. Hydroponic systems work by allowing plenty of root aeration. Deep water culture (‘DWC’) is one of the fastest ways to grow the biggest home-grown cannabis plants. But the key part of the system is the air stone (or air-pipe) which pumps bubbles of air into the nutrient solution. Oxygen allow the roots to thrive in an environment of highly aerated nutrient solution. Without air the roots would simply rot.
Q. What is the cannabis tap root and why is it so important?
A. The tap root is the strong main root which emerges from a germinated cannabis seed. Experienced growers know it is important not to damage the tap root, doing so will slow down plant growth. But contrary to popular opinion the tap root is not essential to cannabis growth. Plants grown from cuttings don’t have a traditional tap root, yet they still produce large plants which are genetically identical to the mother plant.
Q. Why is pH of water so important?
A. The cannabis plant relies on plant biology at cellular level to allow the roots to thrive. For soil growers the pH is less critical since the soil can buffer small fluctuations in water pH. For hydroponic growers pH is critical, if the pH (or temperature) is wrong the cannabis roots will not be able to absorb nutrients even if they are available. Optimum pH for hydroponic growers is around pH 5.8, and the most experienced growers have two pH meters. Eventually all pH meters need replacing and if you rely on a faulty pH meter it can cost you the entire harvest.
Medical cannabis. Are cannabis roots medical cannabis?
Most growers throw their cannabis root system away at harvest. These days, most of the focus is on the quality and effects of the THC-rich sticky buds. But as far back as the 1st century, Pliny the Elder wrote in his Natural Histories that a concentrated liquor made from boiling cannabis roots in water relieved stiffness in the joints, gout, and related conditions.
There is an increased interest in the medical uses of cannabis roots. That’s partly because so many people are now growing their own marijuana seeds, and partly because the roots are nearly always discarded. Boiled cannabis root soups were historically said to treat fever. Whereas crushed raw cannabis roots were said to be good in paste form to treat burns.
Scientific analysis of cannabis roots
There are several interesting ingredients found in cannabis roots. A scientific lab analysis showed the presence of the following compounds. But note, these levels will probably vary from plant to plant and possibly from one variety of cannabis to another.
Alkaloids included cannabisativine (2.5 mg/kg) and anhydrocannabisativine (0.3 mg/kg); carvone and dihydrocarvone; N-(p-hydroxy-β-phenylethyl)-p-hydroxy-trans-cinnamamide (1.6 mg/kg). Different sterol compounds include sitosterol (1.5%), campesterol (0.78%), and stigmasterol (0.56%). Other minor compounds include choline.
It should be noted that cannabis roots are not a significant source of THC, CBD, or other known phytocannabinods. This research paper gives a scientific analysis of the compounds found in cannabis roots.
Cannabis roots. A useful future medicine?
Until fairly recently, most people would have regarded cannabis roots as an entirely disposable and useless part of the cannabis plant. Good for the compost heap, but little else. However, with the recent boom in legalised medical cannabis around the world people are constantly looking for new therapeutic uses for cannabis. Don't be too surprised if you start to see various creams and other products made from the roots of hemp and cannabis in the coming years.
The recent increase in scientific research into cannabis and the analysis of cannabis roots has disclosed some interesting natural chemistry in the cannabis root system. The presence of the alkaloid chemicals is of particular interest and it is likely that pharmaceutical companies are already investigating cannabis root chemistry.
However, if you grow your own cannabis from feminised marijuana seeds or autoflower seeds then you can try making your own root extracts. Could cannabis roots be the next chapter in the uses of medical cannabis? We think there is much to learn.