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Root Problems

by Nebula Haze

Table of Contents

Root Problem Symptoms (many different symptoms)

Triggers for Root Problems

How to Treat Root Problems


Cannabis Plants With Root Problems Show Many Symptoms

  • Cannabis may appear overwatered or droopy
  • Curling or cupping of leaves
  • Wilting - either individual stems wilt or the whole plant may wilt
  • Leaf yellowing
  • Brown spots / Burnt spots
  • Other strange nutrient problems
  • Brown or slimy roots - this is often a sign of root rot
  • Smelly runoff water (smells rotting or musty)
  • Leaves may start dying and falling off rapidly
  • Plants drink much less water than usual

Overwatered marijuana plant Overwatered marijuana seedling

Severely overwatered cannabis plant

The cannabis plant below did not have any drainage holes (water could not drain out the bottom of the pot). Notice the strange twisting of some of the leaves. When roots are left in stagnant water for too long, they cannt get enough oxygen and tend to develop root problems.

Over watered cannabis plant did not have any drainage - began drooping overnight after being watered

This particular type of cupping of the leaves below is common among cannabis plants with root problems. In this case, the plant had no drainage from the bottom of the solo cup, so water was just pooling at the bottom for the roots to sit in. Once the grower poked holes in the bottom of the cup, this problems went away (the cupped leaves didn't recover, but new leaves started growing in happy and healthy).

This particular type of cupping of the leaves are signs the plant has root problems.

Sometimes leaves will tend to cup or curl down due to root problems, like the plant above, but sometimes the curl upwards too, like the poor plant below (this was caused by poor drainage and plant was overwatered, leading to a pretty severe case of root problems):

This poor plant did not have good drainage and was overwatered regularly - causing a pretty severe case of root problems

This next plant was also overwatered and had no drainage. Notice how dark the soil is and the green algae growing all along the top of the soil - these are more signs the plant has been overwatered for quite a while. You should never water your plant when the soil is still wet at the top, and if you notice lots of algae growing on top of your soil, it may be a sign that you're overwatering on a regular basis.

Over-watered, no drainage leading to root problems - notice how dark the soil is and the green algae growing on top - these are more signs the plant has been overwatered for quite a while

The grower of the next plant was going on vacation for a few days, so they chose to overwater their plant in hopes it would be enough water until they got back. While they were gone, they had a huge heat wave. So this plant was subjected to overwatering plus heat. A few days later, when the grower came back, they saw that the leaves were cuppping upwards and had turned lime green. The stems and veins of the leaves were turning red. You can see the soil is still dark and wet because the plant stopped drinking after developing root problems.

This cannabis plant's leaves turned lime green when it developed root problems

The plants below developed root rot in a hydroponic setup. This is usually triggered when the roots can't get enough oxygen, usually due to high temps or poor oxidation of the water. Notice the strange burnt appears on some of the bottom leaves. They turned almost white. The whole plant was drooping, especially towards the bottom. The roots turned brown (pictures below).

A cannabis plant affected by root rot - leaves are turning brown, discolored, burnt white tips and edges, curlingA cannabis plant affected by root rot - leaves have spots, burnt yellow tips and edges, curling

The burnt discolored leaves of a cannabis plant with root rot

Root rot! No wonder the leaves were having so much trouble on top.

Cannabis roots in hydro with root rot - brown roots and leaves are wilting - root rot is often triggered by heat


Learn How to Get Rid of Root Rot (common in hydroponic setups)

See even more pictures of cannabis root problem symptoms caused by over-watering, too much heat, and small containers



Possible Triggers For Root Problems

  • Heat - cannabis is more likely to have root problems at higher temperatures
  • Cold - cold roots are unhappy roots - cold shock can cause wilting and other problems
  • Over-watering potted plants - too much watering tends to cause root problems
  • No drainage hole at the bottom of the container - if water can't get out and water is sitting at the bottom of the pot, the roots can "drown" 
  • Muddy or thick soil - if your soil is muddy and thick instead of rich and fluffy, it may mean the soil doesn't hold enough oxygen to support your roots.
  • Small plant in a big container - When a seedling (or small plant) is in a big container, it often has trouble getting enough oxygen at the roots. Until the plant has grown bigger and started to fill up the container, it's important to avoid overwatering. It can help to water just a little bit at a time, in a circle around the seedling, until it starts growing faster.
  • Big plant in a small container - when roots overgrow their container the plant is considered "root-bound" and the plant often shows symptoms of root problems. When this happens the plant needs to be transferred into a larger container to stop the roots from being "choked."
  • Hydroponics - Root problems are caused when there's not enough oxygen in the water, usually caused because it's either too hot or there isn't enough bubbles/aeration 

Certain strains are more prone to root problems than others, but good root practices will allow every plant to thrive!


How to Treat Root Problems:

Step 1: Identify what may have caused the root problem (refer to list of possible triggers above)

Step 2: Address this underlying issue

Step 3: (Optional) Provide your plant with a beneficial bacteria like Hydroguard to help roots recover quickly (more info about root supplements below). Hydroguard will help fight root rot by creating a colony of good organisms to outcompete the root rot.

Don't use H2O2 for cannabis root rot - it's temporarily effective at bestDon't Use Hydrogen Peroxide (H2O2) for root problems! H2O2 is temporarily effective at best when it comes to root problems. By it's nature, even commercial grade H2O2 will be completely gone from a water reservoir after about 24 hours as it reacts with the water to form oxygen (decomposes) until the H2O2 is completely gone.

If H2O2 is added to a water source, it kills most of the bacteria in the water, including any good bacteria, but will not usually be able to kill all bacteria, so some bad bacteria will still be left to repopulate. Because of it's nature, hydrogen peroxide does absolutely nothing to fix the underlying issue that causes root problems, and it kills any postive bacteria in your soil or water so sometimes it can actually make things worse. I think of H2O2 as a temporary bandaid.

Get your own bottle of Botanicare Hydroguard on Amazon.comI personally recommend using a supplement called Botanicare Hydroguard for root problems because I've used it successfully to get rid of a terrible case of Root Rot

Note: Botanicare used to have an awesome root innoculant called Aquashield, but in our tests Hydroguard works even better to create healthier roots and get rid of root rot!

Hydroguard is also much cheaper than most other similar root treatments and is proven to work well at supporting root health in cannabis. Take a look at our root rot page to see pictures of how Hydroguard was able to completely cure a terrible case of root rot.

Other examples of beneficial root supplements include Piranha, VooDoo Juice, Great White (Great White has great reviews, yet is obscenely expensive), Subculture B, Rooters, and Plant Savers. Most of these can be used with both hydro and soil grows. I personally recommend Hydroguard because I've used it successfully to treat Root Rot (and it's also very affordably priced, you can use it throughout your grow without breaking the bank).

One important thing to note is that after you treat the cause of root problems, the old damaged leaves may never recover! With recovery, you should be looking for the problem to stop spreading, and for new leaves to be growing in green and healthy.



Jump to...

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Enough of all the pics with sad or unhappy roots - before you go, here's a picture of healthy roots growing from a new clone!

Merrie Jayne shares her beautiful new roots - this clone is only 10 days old!

Taken by awesome grower Merrie Jayne


Cannabis Root Problems -
Big Symptom Picture: 
Leaf Color: 
Edges Appear Brown or Burnt
Pale Color Leaves
Yellow Leaves - New Growth
Yellow Leaves - Lower, older leaves
Yellowing Between Veins
Veins of Leaves Stay Green
Red or Pink Color on Leaves
Brown or Dark Spots
Leaf Symptoms: 
Yellowing Between Veins
Veins of Leaves Stay Green
Old Leaves Dropping Off
Slow Growth
Abnormal Growth
Leaves Curl Under
Leaves Curl Upwards
Wilting / Drooping
Plant Symptoms: 
Old Leaves Dropping Off
Slow Growth
Twisted Growth
Leaves Curl Under
Leaves Curl Upwards
Plant Wilting / Drooping
Root Symptoms: 
Slow Growing