How to detect and prevent budrot

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.

Identifying and preventing budrot

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.

jesus, that stuff is nasty!

I just found bud rot on my almost done white widow ... im really about to cry...

I'm sorry that is a shame. We are in the same boat now both have to disinfect our grow rooms. Every inch. This is gonna be fun.

Any experienced growers ever heard of spraying a solution of milk and water on plants, i think 1/10 dilution? Just read this over at the cannabis culture forums, milk is supposed to be a natural funguscide?

Dr StrangeBud's Solution
(makes 2 gallons)
[copied form HerbDotCom]

Mix per gallon of WARM DISTILLED WATER:

15 grams Trehalose
2 grams Sodium Bicarbonate
2 grams Potassium Bicarbonate


SHAKE WELL (until dissolved)

Then mix Non-Fat Dry Milk with water
(use directions on box). Each packet of
dry milk usually makes one quart, you
will need 2 quarts. Then add 2 quarts
of the first gallon to dilute the milk
solution to 50%. Save the other 2 quarts
of the Bicarbonate solution in refrigerator
for later.

Take 15 drops of Rosemary Oil (use 100%
pure essential oil) and add it to some warm
water and a small amount of diluted detergent.
(dilute bottled detergent 7 drops per gallon)
Shake Well! Add to your Bicarb/Milk gallon and
shake the living crap out of it.

Take solution and pour into an atomizer or
spray bottle. Spray to runoff, shaking the
spray bottle every few seconds.

Take your reserved gallon of Bicarb/Trehalose
out of the refrigerator and dilute 50/50 with
WARM DISTILLED WATER and water your dry
plants with it.

Water and spray once then again in 3 days.
Do not feed plants, do not water plants for a week
except with your solutions until they are exhausted.
These solutions may be used until the 2nd week of
flowering. It is also possible to go later with applications
as long as it is "misted" off in a few days.

Observe humidity and temperature changes every few
hours but ESPECIALLY during times you normally do not
check. There may be a spike of one of these when you
are normally asleep that gets corrected by outside conditions.

I have used this formula for 3 years with great success
but it takes a lot of handwork as well to identify and
treat mildews, rots and blights. Unfortunately a lot of
these thrive in the same environment parameters that
cannabis require. My 2 cents would be what I told my
friend who asked me to look at his grow room. On the
way there he picked up a wet, sealed empty one gallon
container to collect water for use in the grow room.

Let's face it most of what we fear we ourselves introduce
to our plants. A wet container that has been outside has
the possibility to carry all sorts of unwanted agents of disease.
The water on the outside of the container is an adherent that
can be a vector for spores and all types of wind-blown pests.

The threshold of his grow room had bare cement on the inside
with signs of shoes being worn on the floor. He had more pressure
on the outside of the room than inside making outdoor air leak
in at great volumes (during the rainy season).

I find it much more useful to look at ourselves and our role in
keeping the conditions right for the plants than obsessing about
what compounds we can use to correct what we ourselves are
guilty of.

Please read the CEA article posted on HerbDotCom and consider
wrap and tape on the inside of your grow room to attempt to get
an "air-tight" grasp on mildews, rot and pests.

Dr StrangeBud stopped selling this formula and allowed us to post
it on HerbDotCom. I thought it may help some people here as well.