Marijuana Root Rot

Cannabis Plant Roots
September 26, 2020

Root rot in cannabis is usually a problem by the time of detection. That is because its damaging effects are the signs you see, alerting you to its occurrence. Unfortunately, you do not see the roots buried in the substrate unless you are growing in hydroponics. At any rate, you can avoid the devastating consequences by first identifying the problem and then undertaking the necessary actions to treat and nurture the plants back to prime health.

What Is Marijuana Root Rot and How Big of a Problem Is It?

Marijuana root Rot is a condition usually caused by disease-bearing fungi such as Fusarium, Pythium, and Rhizoctonia. It could also be caused by other pathogens – bacteria, algae, and parasitic oomycetes. Indoors or outdoors, soil or hydroponics, it does not matter. Cannabis plants, especially the younger ones, are susceptible. Unless mitigated, root rot in cannabis plants can lead to a lack of oxygen and nutrients, eventually leading to death.

Root rot in cannabis is not only a short-term problem. Fungi spores, for instance, can dwell in the topsoil for an extended period. With cannabis root rot soil can hold fungi for a lengthy period. They could even be there before you ever planted anything. In a hydroponics system, they could also survive in the reservoirs.

Causes of Root Rot in Cannabis

Since the cause of root rot is pathogens, then the environmental conditions play a significant role.

1. Temperature

Fungi and most microbes, for example, thrive in 20-34°C.

Cannabis roots and plants in general, on the other hand, thrive in these temperature ranges:

  • 22-28°C during the vegetative stage
  • 20–26°C during the early flowering stage
  • 18–24°C during the late flowering stage

As you can see, in maintaining the ideal temperature, you are already providing a condition conducive to the proliferation of pathogens. Still, by preventing the heat from rising further, you can minimize the risk. It’s important that you remain vigilant with root rot during flowering, even in the late flowering stages as it can be very detrimental to your plants still at these late stages of development. Also, remember to monitor humidity when growing cannabis indoors.

2. Overwatering

A damp substrate, caused by overwatering, is another condition that allows fungi and other pathogens to thrive.

Preventing root rot in hydroponics presents more challenges. Being damp is the least of concerns as the roots are already submerged in a liquid solution. If it is warm enough, then that makes it easy for fungi to reproduce. Other contributing conditions include light leak and lack of oxygen as a result of issues with the aeration pump. Lastly, the presence of decaying organic matter in the nutrient solution may also be a cause.

Cannabis Root Rot Symptoms

Detecting root rot is challenging, mainly because the affected part is buried in the substrate. Hence, you would only suspect its presence upon seeing the signs of problems – above-ground.

Pay attention to your cannabis plant’s leaves they will display early signs that there is a problem. The first sign of trouble is when the leaves start wilting or drooping. Almost always, it is indicative of a problem affecting the root system. Soon, you would see yellowing with browning along the edges. A compromised root system would not function efficiently, and so you would see signs of nutrient deficiency. Furthermore, you may also notice that the plant is absorbing less water than usual. Confirming root rot is by digging into the soil to see the roots.

Healthy cannabis roots are white or cream in color. Once affected by root rot, they would look soft, watery, brownish, slimy, and entangled or bunched together.

Is there a Cannabis Root Rot Treatment?

Generally, cannabis root rot treatment is a two-part process. You begin by stopping the disease and then changing the environmental condition to prevent the proliferation of harmful pathogens.

Hygiene. Keeping the growing area sanitized at all times can never be overstated. Remember to disinfect or clean tools and other equipment before bringing into the grow room for use. That also includes you and your clothes.

Beneficial Bacteria. Some beneficial bacterias can help prevent and stop root rot. Hydroguard is one brand you could try. In particular, it contains Bacillus amyloliquefaciens. Like other Bacillus species, it helps combat harmful bacterias, fungi, and oomycetes. However, it survives better, including in hydroponics nutrient reservoirs. Furthermore, it also helps lower salt concentrations in the tissues of plants.

How to prevent root rot in hydroponics? At the very least, change the water once a month to prevent one type of beneficial microorganism from overgrowing the others. Some people even do it weekly. Also, make sure that the pump(s) works properly. The better the aeration, the more oxygen, and carbon dioxide dissolved into the water. Root rot in cannabis plants is less likely to occur in an O2-rich nutrient solution. CO2 does lower pH levels, so you need to watch out for that and make the necessary adjustments. Keep the solution’s temperature at around 18-20°C, and not higher than 22°C to prevent harmful pathogens from thriving. Furthermore, clear the reservoir of dead leaves and other debris as they become a breeding ground while decomposing. Lastly, prevent light from reaching the roots and the water so as not to promote bacterial growth.

“Treating and Preventing” Is the Cannabis Root Rot Cure

Marijuana root rot is a generalized term used to describe a condition that may afflict the root system. Not only does it damage one plant, but hidden beneath from plain view, the pathogens responsible also transfer to other plants. Once you see signs of distress, it should be no surprise that some or all of the other plants are also affected.

It also does not help that the visible signs could be caused by other issues. The only way to verify is by digging into the soil to check the cannabis roots. Soil mixed correctly with the right nutrient levels can be a big help, it may need to be amended. That should be easier if you are growing the plants hydroponically. Once confirmed, your best way of defeating the dreaded disease is by doing two things simultaneously. Treat the disease by introducing beneficial bacterias and making the environment harsh for the pathogens.

Not all plants can be saved. If it appears so, discard those plants. As for the others, you can only hope that your countermeasures work. Discolored leaves – leaves start turning yellow and eventually turn brown if not dealt with, once they turn brown the leaves will never turn green again. They are done. What you want to see are new growths – that is your cue that the affected plants are recovering.

Follow the recommended guidelines on keeping the grow room clean and ensure optimal environmental conditions. By doing this, not only can you prevent root rot in cannabis but also deal with a plethora of other ailments. You will also have enabled the plants to grow at a vigorous rate, produce a ton of buds packed with trichomes.