Bud rot is a significant yield and quality constrain for many cannabis growers! Also referred to as botrytis, this problem is quite common, and it tends to attack your largest, thickest buds, killing them and wasting away months of hard work. 

Hence, it’s important that you learn how to identify and stop bud rot successfully, given that this problem can destroy your entire harvest.

What Is Bud Rot?

Bud rot is a common type of mold or fungal pathogen that develops inside cannabis buds. Although the appearance of this mold commonly occurs in the later stages of bud development, it typically attacks the stem inside of the bud much earlier, but remains dormant. 

Once the conditions become suitable, the mold rapidly rots the stem and quickly spreads to the outsides, resulting in bud death. Often, the affected buds will develop dusty white spores that can be quite problematic as they easily spread to other parts of the plant and throughout the grow space.

Besides being frustrating, bud rot is a potential cause of economic disaster, destroying an otherwise healthy harvest. Unfortunately, it’s rather difficult to detect the problem in its early stages of development, and denser buds are more vulnerable. 

But the good news is that the causes of bud rot are pretty straightforward. This means that successfully salvaging bud rot is possible with the correct information. 

What Does Bud Rot Look Like? 

bud rot

Identifying bud rot can be pretty difficult, especially for those new to cannabis growing. So, let’s quickly go through the most common but not very obvious signs of bud rot weed: 

Bud rot infection will become visible in certain parts of the plant. It commonly starts infecting the larger, denser buds, especially those grown indoors. Outdoor plants can also be affected by this type of mold. They usually develop patches all over, especially after a few rainy days and towards the end of the season when your buds are big and dense. 

Bud rot typically starts by infecting the stem inside the buds. Although it can be hard to see from the outside, the stem will soon start to appear gray and gooey. The rot will further spread to the buds, forming a wispy, gray web or white dust (spores) on top of them. 

Please note that once your buds begin to rot, they can no longer be saved, and the high chances are that the whole plant is infected as well. 

As bud rot advances, the buds in question will easily separate, revealing a dark brown or gray and possibly dusty inside. The dust spores can easily be spread to other healthy plants by wind, water, or people. 

Therefore, if you suspect bud rot, you should immediately inspect your plants and check between the spaces in the buds. If any crops are infected, isolate them before cutting and discarding the affected areas. This allows the rest of the plant to continue growing normally. But if the infection is widespread, consider cutting down and discarding the whole plant to protect your other health crops. 

You can easily identify mold in cured buds by carefully breaking them apart. Infected buds will have a gray web or dusty inside. Immediately discard the product as it is not safe for consumption. Other ways to identify mold in cured buds include a musty, old smell and a sour taste that lingers at the back of your throat. 

Identifying Bud Rot Early 

Cannabis bud rot begins as a fluffy and white growth that develops in the middle or on the sides of your dense buds. 

Within the shortest time, however, the white mold will darken into a gray/brown growth that rapidly burrows into the heart of your buds. At this point, the fungus is already taking hold. And you may see its initial stages of development on the sides of the buds, allowing you to deal with the infection at its early stages. 

Keep in mind that unless you are very keen, the chances are that you probably will never see the initial stages of mold development before it quickly darkens and begins rotting your buds from the inside out. 

Once parts of your plant are infected, the buds may initially look okay on the outside. But soon, you’ll notice that they’re dying in patches, i.e., the affected areas start drying out, becoming easier to pull apart. And depending on the species of mold/fungi infecting, the insides of the buds will turn purple, brown, or even gray. 

What Causes Bud Rot? 

Bud rot weed is caused by a destructive type of fungus referred to as Botrytis cinerea. While Botrytis is the most common type of fungus that causes cannabis bud rot, there are also other types of fungus that can attack buds. However, the symptoms and effects are generally similar. 

Botrytis fungus attacks buds and causes them to rot from the inside. Luckily, healthy plants won’t develop bud rot unless, of course, exposed to an environment that triggers bud rot. 

The most common conditions that cause bud rot to thrive include: 

  • Wetness or high humidity 
  • Mild/cool temperatures 
  • Big fat buds and dense foliage 
  • Poor ventilation or insufficient air circulation
  • Sick plants or weak plant immunity 

How To Stop Bud Rot When Growing Cannabis 

The most effective way to prevent cannabis bud rot is to understand the conditions that allow it to thrive. Fungi thrive in warm, humid, and damp environments with poor ventilation. Weak genetics with poor immunity are another major cause of bud rot. 

Therefore, it’s safe to say that the first step to stopping bud rot is selecting robust genetics that are highly resilient for your grow space. Secondly, keep humidity levels below 50-55% and allow appropriate air circulation in moderate temperatures. 

Preventing Bud Rot Indoors 

  • Grow with mold resistant strains- Bud rot can be mostly avoided by choosing the right types of strains to grow with. Growing with certain mold resistant strains that are used to growing in warm humid environments is a good start.
  • Maintain humidity levels below 50-55% RH– This is is perhaps the most effective way to prevent bud rot development. Botrytis rarely grows in dry environments, hence, it’s critical that you learn how to control humidity levels in your grow room.
  • Do not expose buds to wetness– Buds left in damp environments and places with very high humid conditions will develop mold. Don’t leave your buds sitting in such conditions for long. 
  • Sufficient air circulation- Ensure your grow space is adequately ventilated to promote good air circulation, allowing your plants to continuously get cool, fresh air. 
  • Remove affected buds immediately- Carefully get rid of any buds that may be affected by bud rot and ensure that the rot does not touch any other parts of the plant! While this prevents the rot from spreading, you must maintain appropriate growing conditions. Understand that mold spores are always in the air, and they’ll readily attack your plants whenever conditions are right. 
  • Avoid huge temperature differences between day and night– Protect your grow space from experiencing big temperature ranges. Experts recommend keeping temperatures at  75°F or 24°C while ensuring your crops don’t get cool or hot. 
  • Defoliate your plants- Big leaves or even small leaves touching each other can trap moisture between them. Consider removing some leaves, especially if your plants are excessively leafy. This helps lower humidity levels around the buds and the entire plant. 

Preventing Bud Rot Outdoors 

  • Get a resilient strain ideal for your local climate- Consider your local climate before buying strains. For instance, if you live in a place with a rainy climate, then fast-flowering, mold-resistant strains are your ideal choice. An excellent example of an outdoor auto-flowering strain is Purple Punch Auto, which will germinate and be ready for harvest in as little as two months, long before the rainy season starts. 
  • Shake plants- If your plants are wet from rain or covered in morning dew, you can protect them from mold development by shaking the plant to ensure the leaves dont become a breeding ground for mold spores. 
  • Protect buds from rain- You can always install a tarp above your plants when you expect rain. Ensure the tarp is held by the center area so that rainwater runs off the sides instead of collecting in the middle of the tarp. 
  • Bud rot removal- This is an effective way to stop bud rot from spreading. Immediately remove and discard any rotted parts of the plant, including buds, while being very cautious not to let the rot touch other parts of the plant. You can move the plant to an area with the best growing conditions to prevent mold from developing. 

Final Thoughts 

Bud rot is a devastating fungus that can turn your whole, otherwise successful, harvest into a total loss! Remember that mold spores are always in the air! And it’s only a matter of when they get the right conditions to develop. Hence, it’s critical that you learn how to prevent bud rot effectively. 

Keep in mind that once bud rot has set in, there’s not much you can do to stop the spread of the destructive fungus. The most effective way to stop bud rot is by maintaining the best environment and using more resilient cannabis strains. 

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