Root Rot

Cannabis Root Rot – Slimy, brown, twisted or unhealthy roots are caused by unwanted pathogens in your hydroponic tank!

The marijuana plant on the left is healthy, and the plant on the right has root rot. The curled, drooping, unhealthy leaves are the result of the plant not being able to get enough oxygen through the roots. Root rot symptoms often look like a soil plant that has been severely over or under-watered.

Straight to the Solutions for Root Rot!

An example of what cannabis root rot can look like ‘under the hood’. Every infection looks a little different, but brown roots are usually the main symptom. It may affect all or just parts of the roots, and the sick sections usually become slimy or mushy and start twisting together.

Healthy Cannabis Roots Are White or Cream Colored!

Root rot can be caused by several different organisms including types of bacteria, fungi, algae and parasitic oomycotes. Although the symptoms are similar between different types, they don’t always look exactly the same.
However, growers generally refer to all types of unhealthy root browning as just ‘root rot’.

Root Rot causes droopiness and other symptoms similar to over or under-watering

The Most Common Triggers for Root Rot Are Light Leaks, Heat & Lack of Oxygen in the Water

Because cannabis root rot can be caused by different pathogens, a solution that solves the symptoms of root rot for one grower may not necessarily work for another grower. What’s attacking your roots in California might be completely different from what’s attacking the roots of a grower in Australia. That being said, there are tools to fight against root rot no matter what kind you have!

The brown tinge on these young roots is the first sign of root rot.

Some root rot affects roots below the water. Roots above the water stay white and healthy. This is why keeping a small air gap under net pots is good.

This air gap helps because it’s full of oxygen. It makes it hard for bad stuff to grow.

Even roots above the water can turn brown. But, the white strands you see are new roots. They show the plant is getting better.

These new roots cover the old, brown ones. It takes time for the brown to go away.

Brown, infected roots often twist and bunch together.

This twisting is because of the infection. Healthy roots stay apart, even in a reservoir.

A mass of root rot. The grower believes that the water level in the reservoir was too high

Cannabis roots with root rot sometimes look mushy or slimy and can almost look like they’re covered in snot

This case of root rot was caused by a brown algae bloom. Brown or green algae is especially common in hot temperatures or when there are light leaks!

Important: The Following Roots Are Stained from Nutrients – They Are NOT Brown from Root Rot

Nutrient-stained roots are not slimy or smelly. They are all the same color. You can see each ‘strain’ on healthy cannabis roots.

Leaf symptoms or wilting on the plant itself is not seen. This shows the roots are healthy.

The first sign of root rot is wilting or drooping. Sometimes, you won’t see symptoms at first. Root rot often hits right after disturbing the roots.

It’s especially common with young plants. Try not to disturb young seedling roots. This helps them grow strong and avoid root rot.

This cannabis plant was healthy the day before. But, it started looking weak after a transfer. The thin, light plastic of the reservoir might have let in too much light.

This made it a perfect place for root rot. The temperature was also very high, around 85°F (30°C). This was not good for the plant.

Cannabis root rot can cause leaf symptoms that can look like almost anything: cannabis leaves get burnt edges or tips; yellow / bronze / brown spots or stripes; nutrient deficiencies; clawing and curled edges; and other unusual leaf symptoms.

Curling and other typical signs of root problems are often present

Root rot can cause curling leaves and brown or burnt patches

Sometimes, a plant with root rot looks fine except for its roots. Don’t ignore this problem. You will likely start getting symptoms!

What Causes Root Rot in the First Place?

Root rot is not just one problem. It’s many symptoms caused by different types of organisms. We call them all ‘Root Rot’ because they make roots look gross and brown.

These harmful organisms show up for the same reasons. They all cause the same problem.

So, what causes root rot? If you’re growing in soil or coco coir, it’s mainly because of stagnant water at the roots. If your plants sit in old water, it’s a breeding ground for bad organisms.

Root rot is a major problem to look out for in DWC many factors can cause it to show up. The most common are:

• Heat: A warm reservoir makes it easier for bacteria to reproduce. In fact, keeping a cool reservoir makes for an environment in which harmful bacteria/fungi/etc. just can’t survive.
• Light leaks: Light in your reservoir equates to a population boom for some of the smaller, unwanted populations living.
• Lack of oxygen in the water: When you remove the air and agitation from your reservoir water, it’s party time! A gross, smelly, sad party.
• Agitating young roots: Young roots need time to build up their defenses. Moving them not only weakens them, but it potentially exposes them to new pathogens.
• Decaying matter in the reservoir: Old bits of dead leaves can be the start of something bad. Make sure you fish any plant matter out of your reservoir when you see it. Except for your roots leave those in there.

Your cannabis plant has started drooping, leaves are getting sick, and roots are brown, twisted, smelly and/or slimy. These are all signs you have cannabis root rot

When a plant is wilting or drooping, whether it is in soil, coco or hydro, it is almost always a sign that’s something is going on at the roots.

The wilting is often soon followed by other symptoms to the leaves, especially burning, brown spots, nutrient deficiencies, spotting, and other unusual leaf symptoms.

Root rot can cause a wide range of symptoms, because without the roots the plant is shutting down!

Plants with root rot often start drinking less water. If you notice symptoms in your cannabis plant, make sure to take precautions to stop root rot from getting worse!

Some brown roots may eventually turn white again after the root rot is gone, but it’s important to note that damage is permanent on the leaves. Brown leaves will never turn green again. You need to watch the roots and the new leaf growth for signs of root rot recovery.

Root rot mostly affects marijuana plants in hydroponic systems, but roots can also get pathogens as a result of over watering your plants in soil or other medium. Basically, anytime the roots are sitting in wet conditions for too long without any oxygen, they are at risk of developing root rot.

• Cannabis plants with root rot almost always appear overwatered or droopy (sometimes plants wilt overnight!)
• Brown, slimy or smelly roots
• Plant leaves often start turning yellow or white
• Leaves may start dying and falling off rapidly
• Oftentimes you’ll see what appears to be a random mix of nutrient deficiencies on the leaves ‘“ this is due to the fact that the plant can’t absorb nutrients properly at the roots even if they’re there
• Plants may drink much less water than usual

Now that you know what root rot looks like and how to get it, it’s time for cannabis root rot solutions!

Solution: What to Do About Marijuana Root Rot, Algae Growth & Slime in the Reservoir

Dealing with root rot can be tough. Many growers think it’s easier to start over. But, there are ways to fix your plant for good!

To get rid of root rot, you need a two-step plan. You must:

1. Treat the plant’s root directly with something that will help protect them against root rot
2. Change the plant’s environment so that root rot no longer has a good place to grow.

Follow this list to fix root rot for good. Remember, sick roots won’t get better. You want new, healthy roots to grow.

Learn how to prevent and treat cannabis root rot

1.) Add Beneficial Root Bacteria – Crucial!

Some growers add beneficial bacteria to their water. This helps prevent and treat root diseases. You can use Hydroguard, VooDoo Juice, Great White, and Rooters with both hydro and soil grows.

Hydroguard

Hydroguard is a good choice. It works well for hydroponic cannabis growers. A small bottle can last all grow season.

Hydroguard has a special bacteria called Bacillus amyloliquefaciens. It fights many root problems. It also might help lower salt in plant tissue.

Great White Root Powder

Great White gives roots good stuff to fight root rot. Some growers didn’t see results, but others did. It depends on what’s in your tank.

Trying different supplements can help. Great White is cheap, so it’s worth a try if you’re still struggling.

2.) Lots of Bubbles

Getting oxygen into your water is key. Buy a medium air pump and big air stones for your hydroponic system.

More bubbles mean more oxygen. This helps roots grow strong. Just make sure roots aren’t too disturbed.

Root rot can’t grow in oxygen-rich water. Your plants will grow faster with more oxygen. I use one EcoPlus 2 Air Pump w/ 2 Outlets for each 10 gallon container. This ensures plenty of oxygen for healthy roots and growth.

You’ll need 3/16-inch standard aquarium tubing to connect everything. Use black tubing to block light.

This method has worked well for me. I haven’t seen root rot since I started using this air pump/air stone combo with Hydroguard. Many pumps and air stones work well, as long as you see lots of bubbles.

3.) No Light Leaks in the Reservoir!

Your roots don’t like light. That’s why it’s bad. But, bad organisms that attack cannabis roots love the heat and light from grow lights!

So, hydro growers want it dark in their DWC reservoirs. You should not see any light where your roots are.

You don’t need to worry about fixing light leaks with a dark, thick tub as your water reservoir.

To keep your reservoir dark for your marijuana plants, remember these tips!

1. Consider the Material & Thickness of the Reservoir Tub: Darker and thicker material lets less light through.
2. Consider Reflectivity: Pale colors reflect more light and heat. But, you can cover the lid with a reflective material to increase reflectivity.
3. Check Thoroughly for Light Leaks! You may need to get down low and look up to see them!
4. Use Opaque Tape to Cover Any Light Leaks ‘“ Electrical tape and reflective tape are great for covering light leaks.
5. Use Dark (Light-Proof) Tubing: This protects the water from light exposure.
6. Light-Proof Your Net Pots. Neoprene net pot inserts are great for filling in net pots instead of clay pebbles. They won’t let any light through. Other good options include net pot covers.

All the Hydroguard, Great White, H2O2 or other root supplements in the world can’t solve root rot if there’s a light leak!

4.) Keep Grow Room Cool

Lower the temperature of the grow space under 80°F, and even better under 75°F. This also lowers the water temperature in your reservoir. Water can’t hold much dissolved oxygen at higher temperatures. Your plants need oxygen to ‘breathe.’

Getting more oxygen to the roots helps fight root rot and makes your plants grow faster. If it’s too hot, you’re more likely to run into root rot and droopiness.

In an ideal world, the water in your reservoir should be around 72°F (22°C). Some growers go to great lengths to keep their reservoirs cool. But, using a great supplement like Hydroguard can let you keep the temperature a few degrees higher without problems.

5.) Avoid Disturbing Roots, Especially Young Plants

Watch over your roots and change your reservoir water regularly in a hydroponic setup. This is especially important in the flowering stage when the plant is very sensitive to nutrients and pH. Changing your water every 7-10 days helps your plants get better access to nutrients. It also prevents deficiencies and toxicities.

However, young seedlings or clones need special care. They don’t have good bacteria around the roots yet. They also don’t have a biofilm that protects the roots against pathogens.

During this initial period, a full reservoir change can upset the balance. Your roots have to ‘start over’ from the beginning.

So, if you struggle with root rot, only top off the reservoir with additional nutrient water for the first 3-4 weeks. Wait until your plants have grown lots of roots with a healthy biofilm before doing a full reservoir change.

6.) Keep Everything Extremely Clean & Sterile

In a hydroponic system, keep dead roots and leaves out of the reservoir. They can cause bad bacteria to grow. If you see organic matter, remove it right away.

Also, keep your grow area clean all the time. This stops bacteria before it starts. Clean all grow items before starting to kill bacteria or fungus.

Hydrogen Peroxide (H2O2) Is Only a Temporary Solution: Use alongside something else for more long-lasting prevention!

Some people use hydrogen peroxide to treat root rot. It kills bacteria and pathogens, including root rot. But, it only works for a day or so because it turns into oxygen and water.

So, if you use hydrogen peroxide, treat your water daily to stop root rot from coming back. I’ve tried commercial grade H2O2 and didn’t see any difference. I don’t recommend it as a long-term cure!

Why Not Use Hydrogen Peroxide? H2O2 is only temporarily effective at best when it comes to getting rid of root rot. It makes me sad when people use H2O2 for root rot because it doesn’t work well.

H2O2 causes bubbling near dead roots, making people think it’s helping. But, it doesn’t really help the plants. And, all the H2O2 is gone from the water in 24 hours.

H2O2 kills most bacteria in the reservoir, including good ones. It doesn’t solve the root rot problem. You can’t just sterilize away root rot.

I recommend Botanicare Hydroguard for marijuana root problems. It has worked for me to get rid of root rot. Look at the pics below.

Hydroguard is also cheaper than most root treatments and works better.

Take a look at what happens with the roots from using a supplement like Hydroguard.

What you are looking for is new healthy white roots growing out of the old brown ones. As the root ball grows, you won’t see the old roots anymore. After you see recovery, some growers cut off old roots. But, I often don’t.

Roots are beginning to recover

Notice the new white roots growing out of the old brown dead ones within just a day or two of receiving Hydroguard in the reservoir. By this point, the plant has stopped showing any new symptoms and appears to be growing normally.

Roots are now mostly recovered below

Notice that you can barely see any signs of the old brown, and all the new roots generally appear white and healthy. The plants on top are lush, healthy, and fast-growing, though the old burnt leaves never recovered.

In addition to treating root rot, I like to use Hydroguard or as a preventative. It is surprisingly effective even in warm reservoirs. Hydroguard have definitely gotten me through a hot summer before.

Since I first started using Hydroguard in DWC, bubbleponics, and other hydroponics, it has successfully prevented me from getting root rot as long as I keep using it. I also use it when growing in soil if I suspect root problems.