The cannabis root system. The key to healthy plants

The cannabis root system.  The key to healthy plants

Cannabis growers around the world pride themselves on their ability to grow healthy plants with plenty of large sticky buds.  For many people in the home growing community the goal is maximum bud quality and maximum harvest quantity.  But what goes on below the ground is just as important as plant growth above the ground.  Healthy and extensive cannabis roots below the ground allow a large and productive harvest above the ground.  



Cultivating a healthy root mass is essential, but just a few basic mistakes will severely limit the ability of your plant to produce the large root network which will support a top quality plant. The most common mistake with indoor cannabis growing is over-fertilisation caused by the use of nutrients which are too strong.  The excess minerals damage the roots (‘root burn’) which limits root growth.  In soil-grown plants the most common error is over-watering, this reduces essential root aeration.  If the roots don’t get enough air they are not able to develop, and this restricts plant growth above ground.  Carry on reading to understand the basics for healthy cannabis roots





Q.  Which insects can attack the cannabis root system?

  1. 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).  


Q.  Can the cannabis root system become diseased?

  1. Yes, Pythium and a variety of related waterborne root diseases can slowly destroy the roots.  Prevention is the best form of cure, keep the riots oxygenated and ruthlessly remove affected plants from your grow room.

 root system


Q.   Roots would normally rot if left in water - why?

  1. The 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 in to the nutrient solution.  Air 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

  1. 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?

  1. 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.  




One of the benefits of hydroponics over soil is that hydro often produces faster and larger root growth which allows larger plants and harvests.  However, hydroponics can be more technically demanding and complicated than growing in soil.  Find out which grow system suits you best, and remember that healthy roots are essential to the health and productivity of the cannabis plant.

The cannabis root system.  The key to healthy plants
December 24th 2015

Leave a comment



2020-09-27 15:22:15

@stevan... Move your lights higher from plant, causing the stems to stretch, in which, plant will grow taller..

Raymond Hux

2020-09-27 15:20:44

@stephen... Move your lights higher from plant, causing the stems to stretch, in which, plant will grow taller..


2018-02-22 22:58:31

There’s lots you can do to get healthy root growth, whether you are growing in soil or hydroponically - read more about how healthy roots means higher yields


2017-10-24 16:02:21

jojo, 20th October. Probably there isn't much you can do about your roots during the grow, just keep feeding and offering plenty of light and hopefully the plant still delivers!

Jo jo

2017-10-20 13:56:02

My plants root looks healthy at the bottom but the top is entwined tightly this ok?


2017-08-10 09:16:25

Stevan, 7th August 2017 Some plants can be stunted by environmental conditions. Low temperatures, nutrient burn, lighting conditions and other factors could all cause issues.


2017-08-07 14:58:10

So, my plant is growing properly. However, if you say that I will have full grown plant ready to harvest in just 3 months, that's not happenin. My plant has been growing for a months and a half and it's 20cm of height. What's wrong? Thank you


2017-07-19 08:54:57

Dirk, 14th July 2017, once you put the seed in the basket you should see germination inside a few days. Eventually a main root will emerge, and a full root system will follow. Usually, after 3 month approx you should have a large cannabis plant to harvest


2017-07-14 15:21:15

How is the traject from seed to plant when do you put it in the basket as in the pictures


2017-02-16 10:44:33

James, 16th Feb 2017. The roots shown in the blog were grown in deep water culture systems. The tubes are out of sight, around the back of the picture. If you grow in deep water culture, with a powerful air stone (30 litre per minute +) you should get an extensive root system as shown :-)

james nanasy

2017-02-16 04:31:31

The plant in the picture is a hydroponic grown plant ? There are no tubes I see, so how can someone grow this way...... I'm a 4th year indoor pro-mix cocoa grower , in 7 and 10 gal fabric pots and general organics feed every other feeding gets just water.....can u give me a way to grow one plant as in picture ??