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How I detect and prevent budrot?

Smokin Moose

Fallen Cannabis Warrior
Budrot (Botrytis) is a very common worldwide fungus that attacks both indoor and outdoor crops under certain conditions. “Budrot” is also known as “brown rot”, “grey mold” and other names. Airborne Botrytis spores can be found everywhere, all times of the year, and will attack many different species of plants. Botrytis will attack flowers, and eventually leaves and stems.

Growers running sea of green, perpetual harvest, remote grows, outdoor, or multiple strains (each with different flowering periods) should keep an eye out for Botrytis near harvest time.

Outdoor growers need to be hypersensitive to weather conditions near harvest time. Rain, morning dew, frost and cool fall nights may increase the risk of budrot and powdery mildew.

Fully developed marijuana buds provide ideal conditions for spore germination: warm and moist plant tissues. Botrytis will initially attack
the largest and densest buds in the garden, because they provide the ideal conditions for germination. Weak plants will also be attacked rapidly.

Budrot will infect and turn colas to mush in a matter of days and may destroy a crop in a week if left unchecked. Botrytis loves warm, and humid (50% or over humidity) conditions. Lowering humidity will slow and stop spore germination. Good ventilation and decent air circulation help prevent infection.

A grow room may smell noticeably moldy if Botrytis has attacked one or more colas. Once a cola has been infected, Botrytis will spread incredibly fast. Entire colas will turn to brown mush and spores will be produced, attacking other nearby colas.

Ventilation may spread viable spores throughout the room.

Measures to prevent budrot in the final stages of flowering:
* Early veg and flower pruning of undergrowth to promote air circulation

* Hepa filter room and intake air sources.
* Introduce low levels of ozone into room air. Ozone is effective against pollen, podwery mildew and other airborne spores.

* Lowering room humidity (warming nighttime air and venting frequently or using a dehumidifier)
* Decreasing watering cycles and amounts to reduce room humidity

* Large, dense colas should be periodically inspected. Brown tissues deep within the bud will smell moldy and may become liquid.

* Removing fan leaves during the last few days before harvest to promote air circulation

* Serenade (thanks vaaran)

"Serenade controls the following: ....Botrytis, Powdery mildew, Downey mildew..."

"Certified organic by OMRI and EPA/USDA National Organic Program, Serenade offers growers the luxury of application without weather or timing restrictions and there are no phyto-toxicity issues"

"To apply, simply spray on leaves and shoots to provide complete coverage. Best results will be had be pre-treating plants before signs of disease set it and then every week to protect newly formed foliage"

What if budrot is found?
Once budrot has been detected, the grower should isolate infected buds by removing them from the growroom immediately and harvesting the infected colas, followed by a rapid dry of the harvested colas. Take immediate steps to reduce room humidity. Afterwards, the entire crop should be carefully inspected for infection and damage.

The grower may want to harvest early if more than one rotting cola has been found. Spores may have spread and are germinating deep within other colas.

Can I salvage budrot-infected colas?
Yes. Remove the infected colas from the main room, Trim out the infection (Trim more than you can see – Botrytis often infects adjacent tissues) and quick-dry them. Re-inspect buds – they should not smell moldy.

Smoking infected buds is not recommended.
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New Member
Please help: I noticed but rot, harvested the of noticeably infected plants in the 7th week, cut out the rot I could find and threw it away. It looked like the bud mold continued to flourish on dry bud, because everything I have no is dry and in a room with a dehumidifier.

Question is, I have many many more than I just cut down tonight, and what can I do to prevent these flowers from being taken over?

What, if anything, can I do in the drying stage to salvage the crop?

I really need advice.



New Member
Good air circulation is critical during the final couple weeks of flowering. Leave your fan on 24/7 till harvest.

I definitely agree with Weed420,good air circulation is key in having healthy plants and lowering humidity especially in the last few weeks of flower. Find ways to lower your humidity, I am not sure if you foliar feed or spray your ladies but that is a no-no at the end of your flower cycle. Increasing air flow, raising temperature, circulation fans, and a dehumidifier are a few ways to help out. You should definitely invest in a humidity reader so you can regulate it arround 30-50% which I would say should help out. If you have mold, once I tried raising temps to about 105 degrees for about an hour for some clones and it worked but you also have to take in concideration the size and age in my case. Well thats my 2 cents, hope it helps.

You should try adding more information about your growing environment, there might be some key elements that can help an experienced grower diagnose your problem.


New Member
I understand leaving the fans on 24/7 in the last weeks. I have strategies to prevent this in the future (dehumidifier, little higher temps, fans, etc). The question is this: Now that I have cut everything and it is hanging, are there any recommendations that prevent further damage and spreading, because bud rot continues to spread, even when flowers are drying or dry

Thanks guys.


New Member
I would suggest for you chop off whatever area is infected and then quick dry your buds so that the infection doesn't keep on spreading. Make sure you cut off a little extra bud arround the infected areas so that little if any rot is left.


New Member
I guess I wa hoping for something more than all of the basics, or methods I would find in the grow bible. Currently, I have a oscillating fan on the hanging plants, a dehumidifier, and the temp is about 65, in a dark room. I wish there was a way to keep it more contained or kill the fungus, without taking away the quality of the flowers.

Any more advanced suugestions would be awesome.

Thank you everyone who has helped me, really appreciated.


New Member
If you already have bud rot during the drying process about all you can do is through the bad bud out. You might try spraying it with hydrogen peroxide on them to see if it prevents spreading. Also sulfur pots are supposed to help but I've never tried it. The most important point is to not let your plants get to that point and keeping a fan on 24/7 is the easiest way to stop it.


New Member
Bud rot happens when too much moisture and heat are concentrated on the bud. Mold loves dampness and heat. Could be from too much rain or overwatering. I've heard that water curing will remove the mold and allow you to smoke the affected bud.
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