Rot on Cannabis: Diagnosing, Treating, and Preventing

Rot on Cannabis: Diagnosing, Treating, and Preventing

Marijuana, like other plants, can become infected with harmful pests and diseases. Luckily, the vast majority of them are not fatal. On the other hand, some of these pests can seriously damage and weaken crops. When you know what you’re dealing with, you’ll have an easier time defeating or preventing a marijuana disease.

Marijuana Bud Rot

Bud rot is the most dangerous fungal infection. It attacks the buds of the plant, killing them within a few days. Bud rot is another name for grey mold, a necrotrophic fungus known to science as Botrytis Cinerea. Bud rot is usually characterized by the formation of mold, which destroys the buds of a flowering plant.

What does bud rot look like on weed? As a cannabis plant grows, its buds may initially develop white or hairy spots, similar to a regular fungus. Later, the rot will gradually become brown, black, or slightly purple. As the buds mature, they can become covered in a heavy layer of dark dust and become soft and lose.

Diagnosing Cannabis Bud Rot

Plants begin to rot in contact with fungus spores that circulate around them. These spores are sometimes carried on clothing, and they can also be found in water. And once they start to germinate in the bush, the fungus can quickly spread and hit the whole crop. As a grower, in this case, you may witness botrytis on cannabis — a systemic mold infection. Initially, bud rot is not a common sight when examining marijuana plants.

As a grower, you should keep an eye out for these signs:

  • The edges of the cannabis plants look brown and burned;
  • Cannabis leaves turn red or purple;
  • There are visible spots on the leaves;
  • Abnormal leaf growth is noticeable;
  • Mold is visible.

cannabis edges rot

Cannabis Bud Rot Treatment

When rot infects a cannabis plant, there is a high tendency to lose precious buds. Infected buds are not recommended to smoke because they will harm smokers. If part of the cannabis plant is already infected, remove the formed buds. Take a knife or scissors, dip them in medical alcohol and trim the damaged area. It is recommended to use 90% isopropyl alcohol. After trimming, clean the fresh damage to the plant with alcohol with a cotton swab.

Note that this type of fungus can remain in dead plant materials such as leaves. He will wait for the next opportunity to infect the plant. Therefore, it is recommended to remove the area where one lives. Removing dead leaves means that fungus cannot attack a second time.

Cannabis Bud Rot Prevention

Because treating rot can be so time-consuming, experts advise that you avoid it in the first place.

  1. Experts recommend keeping the temperature over 68°F to avoid the development of rot. When cultivating in the greenhouse at night, use a heater.
  2. Indoor growing helps to avoid infection with Botrytis cinerea, but you still need to monitor the room closely so that harmful particles don’t get in.
  3. When an infection occurs, remove the affected area and avoid infection elsewhere on the plant.
  4. For the easiest way to prevent rot in your indoor garden, try to keep the humidity level low.

Marijuana Root Rot

Cannabis root rot is a widespread and serious problem that can be a real headache for growers. When watered plants do not have sufficient drainage, the roots cannot absorb oxygen and they begin to die. As soon as dead roots appear in the soil, the next irrigation cycle will create the ideal environment for root decay. Root rot weakens plants, making it more likely that they will die.

Infected plants drink less water and grow slower. Root rot is extremely difficult to get rid of. As a result, it leads to stunted growth and a lack of nutrients.

Diagnosing Cannabis Root Rot

The main root rot symptoms cannabis experiences are wilting and dryness. Root rot can take many forms:

  • Burns on the edge of the leaf or burnt tips;
  • Yellow/bronze/brown speck or stripes;
  • Various manifestations of mineral deficiency (roots cannot feed properly) bending of leaves;
  • Formation of “claws” at the tips, and so on.

diagnosing cannabis roots

Cannabis Root Rot Treatment

Plants that become infected with root rot can be almost impossible to rescue, so many growers just dig them up and throw them away. However, it’s possible that the marijuana crop you’re growing outdoors at the same spot (for example, an outdoor plantation,) will be compromised by a fungus next season.

So, how to fix root rot on weed plants? Fortunately, there are methods available to deal with root rot in plants. To succeed in eliminating a disease, you should be comprehensive in your approach by including:

  • Direct treatment of roots;
  • Correction of cannabis living conditions.

Without the second point, the cause of the rot is likely to remain and is likely to relapse.

Cannabis Root Rot Prevention

It is noteworthy that after the disease is cured, neither the affected roots nor leaves are restored. It is only by the state of the new breed that it is possible to judge whether the problem has been eliminated. When a sick brown root grows with a new white one, it means the cannabis has recovered. By taking several preventive measures, the chances of rotting at the roots can be reduced:

  • By providing the right amount of water, keeping careful track of how much you give each plant, and observing the plants regularly, you can help keep your plants alive.
  • Healthy soil enriched with beneficial microbes and bacteria will keep the fungus responsible for root rot under control.
  • Letting garden soil breathe promotes air circulation and prevents the buildup of harmful gases. When you grow plants in containers, you can help them thrive by including a smart pot, which adds oxygen to the soil, and perlite, which ensures proper drainage.


Cannabis cultivation may be a tall order for inexperienced growers. While some issues, such as bud rot in dried weed, are a matter of proper storage, others, like cannabis stem rot or roots and buds infections, require self-education and comprehensive solutions.