Bud Rot or Mold
Extreme Case of Cannabis Bud Rot đ
Sometimes the first sign of bud rot is a few leaves on the buds turn yellow seemingly overnight. The base of these leaves is where the bud is rotting
How to Prevent & Stop Bud Rot (quick summary)
Air circulation â Itâs a really great idea to have an exhaust fan constantly venting out hot humid air and replacing your grow space with fresh air whenever possible. But no matter what, make sure thereâs always plenty of air moving over all the buds and leaves, and through the plant. This can take some planning.
Avoid wetness and especially high humidity â Donât allow buds to sit in damp or overly humid conditions for long. Cover plants when it rains, and otherwise shake them off when theyâre wet. Bud rot is a fungus, and like all fungi, it needs a wet place to germinate.
Consider defoliating extremely bushy plants â If itâs extremely bushy and you canât keep the humidity down, consider defoliating (removing leaves) on the middle and bottom of the plant. Each leaf is constantly adding moisture, and removing leaves helps lower the humidity around the plant. Any leaves that arenât getting light are only stealing energy away from your plant by the time buds are big enough to worry about bud rot. Those leaves are better off gone especially if you need to lower the humidity!
Keep an extremely close eye on your longest, fattest and most dense colas. Almost like a cruel joke, bud rot usually attacks your biggest colas đ
Remove all affected buds immediately â Carefully remove and discard all buds with bud rot, as well as nearby buds â this is incredibly important if you donât want to lose the whole harvest! Donât let anything any of the rot touch other parts of your plant, as it can further spread mold spores.
âWhen I had to throw away most of my plant due to bud rot, I cried a little, on the inside.â
Table of Contents
What Does Bud Rot Look Like?
Usually, a bud rot infection becomes visible in just certain parts. Sometimes just the bigger and denser buds are affected, but other times youâll get patches all over the plant, especially after a few rainy days.
You may see areas on the colas where everything (buds, pistils and/or leaves) are darkening, becoming discolored and/or drying up, unlike the rest of the plant.
The deadened spots usually stand out and catch peopleâs attention, even if growers donât know whatâs wrong, they often instinctively know that something is wrong since the spots donât look like the rest of the buds on the plant.
In addition to the rot itself, you may see white mold on the outside of the bud at first â this is the first stage and it means plants need to be treated immediately! With advanced bud rot, the bud will easily separate so you can see inside. When the bud in question is inspected, it will be dark on the inside, usually gray or brown, and possibly dusty (this âdustâ is fungus spores).
Depending on the life stage, bud rot can lookâŚ
white and fluffy
dark gray or brown (sometimes even dark purple)
the buds can be full of dark speckled dust which easily blows away (fungus spores)
âI lost half my plants last year to bud rot⌠After a couple of drizzly days, I noticed spots, and then I saw that it had spread to all my plants.â
Sometimes you might see a few yellow leaves appear suddenly on some of your biggest colas. It can feel like it happens overnight. That could be a sign that thereâs mold at the base of these leaves. Always investigate any cola with yellowing leaves ASAP. If thereâs mold you will be able to see the leaves are basically falling out, with mold or brown spots being revealed in the middle đ
Different Stages of Bud Rot â Catch it Early!
When plants are afflicted by cannabis bud rot, it starts as fluffy white growth in the middle or sides of buds, but the white mold quickly darkens into gray or brown and burrows deep into dense buds as the fungus takes hold. Sometimes youâll see the initial stage on the sides of buds, giving you a possible chance to catch the infection early.
The Botrytis fungus looks white and fluffy in its initial stage, but youâll probably never even see this stage before the mold quickly darkens and starts rotting the buds from the inside out
Once bud rot has taken hold over parts of a cannabis plant, the buds can sometimes look almost the same on the outside, at first, but they usually start looking like theyâre dying in patches. Often the area will dry out and easily pull apart. The inside of buds can turn brown, gray or even purple.
âI noticed one brown sugar leaf and it came out unfortunately easily, exposing what was inside.â
Some growers might think these drying spots mean that the plant is almost ready for harvest, but you know something is definitely wrong when just parts of the colas are being affected.
Hereâs an example of advanced bud rot on an outdoor cannabis plant
What Causes Bud Rot?
Cannabis bud rot is caused by a type of fungus known as Botrytis cinerea.
In cannabis plants, Botrytis causes buds to rot out from the inside, hence the name âbud rot.â If you crack open an infected bud, the inside will be a moldy dark gray or brown.
Bud rot can show up in many ways. For example, this cola here responded to bud rot by turning purple and mushy. with leaves that becoming crispy and dying. This is what the grower came back to find after a few days of rain.
Did you know? In addition to cannabis bud rot, Botrytis causes problems for many different types of plants, including wine grapes, strawberries and peonies.
Botrytis the fungus is sometimes referred to as âbotrytis bunch rot,â âbotrytis blight,â âbud rot,â âgrey mouldâ or âgray mold.â
When it comes to cannabis, it is often only called âBud Rotâ since thatâs the main symptom cannabis growers are worried about.
Any part of the cannabis plant affected by bud rot should be discarded immediately! This helps prevent further infection and all buds touched by this toxic fungus should never be smoked or used.
Throw Away All Buds with Any Sign of Bud Rot!
This is What Bud Rot Looks Like Ground Up
There are different stages of Botrytis as it matures and tries to release spores. An infection starts as fluffy white mold (or brown mold) and then spreads throughout the inside of vulnerable buds. The inside of those parts of the colas darken to gray or brown. Once that has settled in, the mold tries to reproduce. The insides become filled with dark speckled dust that easily floats and spreads if the bud is cracked open. These are the spores of the fungus, so be careful to avoid breathing in letting this speckled dust ever touch other parts of your plants.
Luckily, healthy cannabis plants will not develop bud rot unless exposed to stagnant air and wet conditions for an extended period of time. Your plants are more susceptible to bud rot, fungus, or mold when the temperature is hot or cold. Aim for a temperature of 75°F (24°C) in the late flowering stage if possible.
How does the Botrytis fungus get to my plants?
Bud rot is spread to plants by dusty gray spores, usually in wind or water.
Most common ways Bud rot fungus spores get to plants
- Wind
- Rain Water
If your plants are never exposed to these spores, they will never get bud rot.
Unfortunately, the spores can easily be carried to your plant by a breeze, rain, from contact with animals, or even by clones from another grow room. Dormant spores can survive in many conditions only to affect your crops another time!
But⌠itâs not so bad. The fungus will never germinate if you take good care of your buds. And in any case, your plant needs a âwoundâ of some sort for the spores to take residence in your buds.
Possible wounds that can let Bud Rot fungus in include cracks in the stem from wind or over-training, damage from caterpillars, snails, worms, white powdery mildew, other pests, and larva, or any other type of injury or weak point can be the point of entry for bud rot spores into the plant.
Luckily, even if your plant has been exposed to spores, Nothing will be able to survive and begin the cycle of a bud rot infection if you provide your cannabis with a cool, dry, breezy environment.
Bud Rot needs warm, humid conditions and stagnant air to thrive.
What triggers spores to grow into a full-blown case of bud rot?
Wetness or High Humidity
How to Control Bud Rot (these are most important!)
The biggest thing you want to focus on is getting the humidity under 50% (most important!) and giving plants plenty of air movement.
How to Prevent Bud Rot
These are the most important points to rememberâŚ
Keep humidity under 50% RH (Most important!) â This is the most important thing you can do to prevent bud rot from growing. Itâs rare to see Botrytis in dry conditions. Learn how to control the humidity. If you donât fix this, the bud rot may keep spreading even after youâve removed all the affected buds.
Good air movement â Create good air circulation and make sure thereâs always plenty of air moving over all the buds and leaves. Make sure your plants are getting access to cool, fresh air.
Keep plant from big temperature swings between day and night â Controlling temperature and keeping the grow space from experiencing big temperature changes can go a long way. Aim for 75°F or 24°C when youâre worried about bud rot, and avoid letting plants get hot or cool.
Remove all affected buds immediately â Carefully remove and discard any and all buds that have possibly been affected by bud rot. Donât let any rot touch other parts of your plant. This helps prevent bud rot from spreading, but itâs not enough if you donât take care of the environment. Remember, the spores are always around, and itâs just a matter of whether they get the right conditions to grow.
Other tips to help prevent bud rotâŚ
Avoid plant wounds. Avoid injuring your plants, especially in the flowering stage. Donât leave open wounds to seep out water and nutrients â cover any open injuries with tape or some other âcastâ until injury closes up. Avoid pests and keep plants healthy. A healthy plant is much less susceptible to all kinds of infections.
Keep some space between buds. Cramming a bunch of plants with a lot of buds in a small space can increase the chance of bud rot. Buds should never be touching each other. Try to make sure every big bud has at least a few inches of âbreathing roomâ to itself.
Defoliate leafy plants. Remove leaves on very leafy plants. If leaves are touching each other, theyâre likely creating wet spots between them. R emove big leaves that are covering or touching bud sites, as well as any leaves that are laying on top of each other. Your plant wonât âmindâ if you only remove leaves from leafy areas, and this prevents moisture from collecting into damp spots, while also improving air circulation around buds.
Watch out. Watch plants closely for signs of bud rot in the late flowering stage, especially on large or dense buds, and especially after humid or wet weather.
When growing outdoorsâŚ
Get a strain meant for your local climate. If you live in a place that has short summers and gets humid or rainy early in the fall, donât get a strain that was developed near the equator!
There are fast-flowering, cold-resistant cannabis strains which are designed for growing outdoors in more rainy climates. For example, many auto-flowering strains have quick lives â perfect for a short summer before the Autumn rain or frost.
A good outdoor strain for those worrying about bud rot might be Auto Frisian Dew, an award-winning, mold-resistant strain made for outdoors. This strain goes from seed to harvest in about 12 weeks. Just plant seeds after the last frost in the Spring, then harvest 3 months later.
AutoFrisian Dew is resistant to fungus like bud rot. This strain is quick to harvest and will grow in any climate which has (at least) 3 warm summer months before it starts getting cold or raining.
Breezy location â Try to plan your grow spot so your plants get a breeze, but not too much wind. This can be tricky, and it may mean visiting the grow spot a few times before planting.
Protect your buds from rain. If you know there will be drizzly conditions, cover your plants with a tarp to protect them from most of the rain. Donât put tarp directly on plants or youâll hurt your buds. Install the tarp up above the plants, and make sure itâs held up by the center part, that makes it so rain runs off the sides of the tarp instead of collecting in the middle.
Shake plants. Some growers shake their plants on dewy mornings or after rain, so any water drops that form on the leaves donât become breeding grounds for spores.
Fungicides, Neem Oil & Burning Sulfur
In the flowering stage, never use fungicides, spray affected buds with Neem oil, or burn sulfur.
These common tactics are not effective at stopping bud rot and will make your buds taste, smell and look terrible.
Some growers use fungicides made specifically for Botrytis in the vegetative stage. But when it comes to cannabis, fungicides can only be used as a preventative before any buds have formed.
If you already have bud rot and canât fix your environment (which is the best way to kill Botrytis), I highly recommend cutting your losses and taking down the plant.
Most fungicides are not effective for bud rot. If you do plant to spray plants, itâs recommended to get one thatâs specifically been developed to combat Botrytis.
Any treatments for Bud Rot should be applied in the vegetative stage as a preventative.
Thereâs nothing you can spray on your plants after bud rot has already formed. Unfortunately, there arenât any effective fungicides or other treatments that are safe to use with cannabis in the flowering stage
How to Stop Bud Rot from Spreading
The inside of dense buds provide a great place for Bud Rot spores to grow, and thatâs the main place youâll find developed Bud Rot on cannabis plants. Once youâve spotted bud rot, itâs important to act immediately.
As soon as even one part of a single bud starts showing signs of grey mold, the rot can spread to the rest of the cola and then to other buds on the plant. If triggering conditions (lack of airflow, wetness) have not improved, a single point of infection can quickly ruin the harvest of an entire plant.
Never Spray Your Buds with Anything!
Bud Rot Removal
- Immediately remove all rotted parts and nearby areas. The only way to stop the spread is to remove all signs of mold from the plant, then move plants to a cool, dry area with a nice breeze.
- Be extremely careful not to let any rot touch any part of the rest of your plant.
What Happens Next?
- harvest the cannabis plant now
- let it continue to ripen, but only if you fix the environment
If your plant has been affected by bud rot, it means they need less dampness and air thatâs more dry. If you can improve the environment, you can allow the plant to continue ripening after youâve removed the infected buds. However, if you donât fix the environment it will usually come right back, sometimes even attacking other buds overnight.
Hereâs how to fix the environment:
- add additional air circulation
- lower the humidity (40-50% RH is optimal in the late flowering stage)
- defoliate leafy plants (remove leaves covering bud sites, through the middle of the plant, and any leaves that arenât getting light anyway)
- prevent wet spots on plant
If you canât fix the environment, I highly recommend cutting your losses at this point. If you know that itâs still going to be cool, humid or wet for your plants, itâs recommended you harvest immediately to prevent further buds from becoming infected. Buds harvested early are better than moldy buds!
Whenever you do harvest your healthy buds, be extremely careful during the drying process. Normally growers want to slow dry buds, but if youâre worried about mold itâs better to dry them faster, with plenty of air circulation and movement.
Bud rot is a mold that develops in the thickest parts of cannabis buds. Read for more information on how to prevent and solve bud rot before spreading!
PSA: Check Your Cannabis for Mold
Spotting mold on bread or cheese is pretty easy, but on cannabis? Not so much.
Hereâs everything you need to know about what to look for, whether itâs safe to smoke moldy cannabis, and how to keep your stash mold-free going forward.
Moldy cannabis usually has a grayish-white coating. If youâre not a seasoned consumer or grower, though, it can be easy to mistake trichomes for mold and vice versa.
Trichomes are those sticky, shiny crystals on the leaves and buds that give cannabis its aroma.
Unlike trichomes, which look like little hairs that almost appear to glitter, mold has a gray or white powdery appearance.
Mold also has a distinct odor to it, so your nose may notice the mold before your eyes do. Moldy weed usually has a musty or mildewy smell, or it may smell kind of like hay.
It probably wonât kill you, but itâs still not recommended.
In healthy people, smoking moldy weed isnât likely to have a detrimental impact on your health â barring the general risks of smoking, of course.
If you smoke moldy weed, you might experience symptoms like coughing, nausea, and vomiting, which are more unpleasant than dangerous.
But if youâre allergic to mold, you could end up with inflammation of your sinuses or lungs and symptoms like:
- sinus pain
- drainage
- congestion
- wheezing
In people with weakened immune systems or lung conditions, inhaling smoke from weed that contains certain mold species can have serious health consequences.
Fungi like Aspergillus, Mucor, and Cryptococcus can cause serious and even deadly infections in the lungs, central nervous system (CNS), and the brain in people with compromised immune systems.
A UC Davis study found these and other types of potentially harmful fungi on cannabis samples bought from dispensaries and growers in Northern California.
You may be tempted to cut off the obviously moldy bits and smoke the rest, but itâs not a good idea. Lifeâs too short for bad bud.
If you can see mold or mildew, youâre better off tossing it. Itâs not going to taste or smell good anyway, and could make you feel sick.
Storage is everything when it comes to preventing mold.
Exposing cannabis to the wrong temperature, light, humidity, and oxygen can promote the growth of mold.
Hereâs what you need to keep in mind.
Avoid the fridge or freezer
Forget what youâve been told about storing your green in the fridge or freezer. The temperatures are too low, and the exposure to moisture can result in mold.
The ideal temperature to store cannabis is just below 77°F (25°C).
Use the right container
Glass jars with an airtight seal are the way to go if you want to keep things mold-free.
Mason jars and similar glass containers help limit the exposure to oxygen and moisture, which can prevent mold and keep your nugs fresh longer.
If you want something a little more sophisticated than a Mason jar, most dispensaries sell containers designed for this exact purpose.
Keep it in a dark, dry place
Direct sunlight and moisture are recipes for disaster when it comes to keeping cannabis fresh.
The sunâs rays can heat things up and hold in moisture. A damp environment can also cause too much moisture to build up if your container isnât properly sealed.
Keep your container in a dark, dry cabinet or closet that doesnât get too hot.
Mind the humidity
Cannabis is best kept at a relative humidity of 59 to 63 percent. Go any higher and you run the risk of trapping moisture and growing mold.
Adding a humidity pack to your container can help. These are little packets that contain a mix of salts and water that help regulate the humidity in your container. Theyâre inexpensive and last a couple of months.
Humidors made specifically for cannabis are another option if you want to get fancy and are willing to spend some extra bucks.
Like most green things, cannabis can develop mold under the right conditions. Learn what to look for and whether there's any way to salvage your bud.