Mold weed seeds

Can I grow seeds from moldy weed?

I picked up a bag of Purple Kush and it has a bit of powdery mildew on it. I picked out the good buds to smoke and some are full of seeds. The seeds seem healthy they are dark brown with those blueish stripes on them like the ones I buy at my local smoke shop. If I grow these seeds are they guaranteed to have PM? Should I try them or just throw them away?

Well-Known Member

Its going to be more likely than if they were from bud without powdery mildew, but no, I don’t think its guaranteed at all.

If the conditions of your grow aren’t conducive to powdery mildew growing, it won’t grow.

Personally, I’d definitely try them, if I was otherwise interested in growing them.

You can just start with one and see what happens. I bet it will germinate and grow just fine with no issues.

If you do have a problem you can always dip the remaining seeds in a fungicide (for preventing “damping off” fungus) prior to germinating them, or treat them after sprouting if this becomes an issue.

There are specific copper-based ones you can use, but a weak solution of hydrogen peroxide will probably work to kill any fungus on the outside.

Well-Known Member

I’ve never thought about it, or researched this, so this is not a smartass question, but curious.
Isn’t that like saying, if I have a cold, and get my wife pregnant, will the baby have a cold when it is born?
I would think if you thoroughly wiped the seed with a peroxide solution on a paper towel, that the seed would be fine.
Am I right? Not right?

Active Member

i would hit the seeds with a mild bleach and water solution, then immediately rinse them off with plain water and get to germinating em. even rinsing them off with plain tapwater would probably get rid of any spores on the seeds.

i don’t know if peroxide will kill the mold or not so i can’t say.

in any case, even if he just grows the seed out without doing any of that i would think all will be fine in the end, mold spores are everywhere, and if he creates an environment favorable to its growth it will most likely grow. it will come down to weather or not he dries and cures the finished product properly as to if he will get mold or not.

Active Member
Well-Known Member

Wow. Don’t hit your seeds with a bleach solution man. Chucky is right on this one. This is kind of a silly question.

What you should take into consideration, however, is that the strain is susceptible to PM, and therefore extra precaution should be taken to ensure your environment is under 50% Relative Humidity at all times.

If you are worried about it at all, mist your plants with a diluted lemon juice/water mixture during the first few weeks of flowering. Never use bleach or peroxide on your flowers.

In my opinion, though, there is no plausible scientific explanation as to why a seed exposed to a few mold spores could cause mold on a plant, it isn’t like the fungus is genetically inherent. Even if it is present on the plant at seedling stage, it can’t continue to grow without optimal conditions, and under 50% RH is not optimal. Hope this helps man.

Moldy Weed – How To Identify, Prevent and Eliminate Mold In Cannabis

You’ve done all of your homework, you’ve invested in good genetics and grow equipment and followed the grow instructions of your favorite cannabis book (or blog) to a tee, yet despite all of your efforts you notice a white powdery substance on your leaves or perhaps some grey fuzz on your buds or maybe some other signs of plant distress that you can’t quite put your finger on. If any of these apply to you, you could be dealing with nearly every gardener’s biggest fear: moldy weed.

Whatever the type of fungal infestation, moldy weed can affect even the most experienced gardener, though if you take the right preventative measures and act timely if you do spot an infestation, you can greatly reduce the risk of mold in your garden and keep your harvest safe. Below we will go through the ways of identifying, preventing and treating various mold varieties once they do appear.

Know Your Enemy: Identifying Common Types of Mold

Molds are a type of fungus, which includes various types of yeast, molds, mildews and mushrooms, have been around for billions of years and are absolutely vital to the cycle of life, acting as decomposers of dead matter. Without fungi, life on earth as we know it would not be possible.

Fungi reproduce through spores, which are found everywhere and can lay dormant until conditions are ripe for them to work. We should absolutely respect their function in the life cycle, however, as cannabis lovers, we want to keep them out of our gardens to the greatest extent possible. Below we present the most common types of fungal infestations in cannabis.

Powdery mildew

These are perhaps the easiest to identify thanks to their easily recognizable appearance. Powdery mildew forms on the surfaces of leaves during the vegetative phase as well as on buds and looks a white powder that someone maliciously sprinkled on your plant.

Starting on the lower branches, it can quickly make its way up the plant. Some growers can mistake it for plant trichomes, which is why you should check the lower leaves first, preferably with a magnifying glass. If you do detect powdery mildew on your leaves, no need to panic. While this mold won’t kill your plants, if it does make its way to the buds, they will be unconsumable.

Powdery mildew results from high humidity and lack of airflow, so to prevent it make sure to keep your grow space well-ventilated and at 50% relative humidity or below. Wipe down the affected foliage with water and then spray with neem oil, horsetail or any other organic fungicide to stop the spread.

Sooty mold

As the name suggests, this looks like soot and is an indication of an insect infestation such as whiteflies and aphids, which leave waste (excrement) on the leaves after feeding on them. This means you have to deal with the pest infestation first, however treatment for sooty mold is rather easy once the insects have been eliminated.

Higher grow room temperatures are usually the culprit here, so make sure you keep the temperature below 25°C and check your plants daily for any bug presence. Once bugs have been detected, use an organic foliar spray such as neem oil to eliminate them. Water alone can then be used to wipe of the relatively harmless mold, but spraying leaves with neem oil will help prevent the return of unwanted visitors.

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Root rot (fusarium)

This is quite a serious infestation, as you can lose your entire crop very quickly. Root rot starts out in the soil and can cause plants to wilt and collapse, ultimately killing them. It can be identified by looking at lower leaves, where it starts as dark spots and the leaves quickly turn yellow-brown in color. The roots turn red under the top soil and the infestation continues upward through the stem, causing it to swell and break open. In this case, prevention is your only cure as there are no direct treatments available just yet.

Once spotted, infected parts of the plant must be removed immediately. Having a healthy soil is key here, so try to add beneficial microbes (i.e. mycorrhizae), keep the soil relatively dry (not soggy) by not overwatering and keep it breathable by using smart pots or fabric pots and add perlite or other mineral that improves aeration and drainage. If possible, replace your soil after each crop or at the very least sterilize it to eliminate any potential spores.

Bud rot (botrytis)

Also known as grey mold, this common fungus can attack roots, stems, leaves as well as buds and is known to spread quickly. It infests plants through the air via open wounds, such as a snapped branch or damaged leaf. It appears as little black dots before developing fluffy white growth in the core or on the sides of buds, which means it usually appears during the flowering stage. It will turn grey and black before becoming a slimy, yucky mess. moldy weed at its worst.

Once detected, there isn’t much you can do as spraying it with chemicals will only leave that taste on your nearly finished buds, so isolating and carefully discarding affected areas is the only real treatment. Make sure your RH is below 50% and that you have proper ventilation throughout your garden.

Recommended Mold-Resistant Cannabis Strains

In addition to prevention, proper genetics can also act as a defense. No cannabis variety is 100% immune to any pest or disease infestation, but there are several out there that are highly resistant to mold and bugs that will help growers sleep a little easier at night.

Even the best strains still need good management

Preventing mold on cannabis plants is very similar to preventing it in a house. Try to reduce humidity and increase air circulation. Outdoor growers may have to hope that luck goes their way on this but indoor growers can use dehumidifiers and/or fans. Make sure there’s a decent amount of space between the plans and if necessary trim them. Removing excess leaves will help improve airflow, but the effect will be completely negated if you simply put the leaves in a bin in the growing area. They need to be completely removed from the growing area. Mold also thrives in waterlogged soil so make sure your watering system gives the plant what it needs and only what it needs. Finally, keep the growing area scrupulously clean. This starts with removing anything which could harbour mold so remove any fabrics and keep pets out (they can bring in mold on their coat and paws). Avoid using plastic sheeting as this traps moisture very easily and therefore attracts mould.

Avoid Moldy Weed And Beat It For Good

As the saying goes, an ounce of prevention is worth a pound of cure. Air flow, humidity, spacing and temperature are all key factors in maintaining a healthy, pest and mold-free environment. Defoliation and preventative spraying with organic products should help keep the bad guys away, but regularly inspecting your garden for any uninvited guests is the best way of preventing a moldy weed infestation before it’s too late. With that in mind, stay vigilant and happy growing!

Mold On Cannabis Plants: All You Need To Know

Mold happens on cannabis in warm and humid growing spaces, it can develop on a plant’s leaves, buds or roots.

  • 1. What is mold?
  • 2. Ideal conditions to prevent mold
  • 3. Mold on cannabis
  • 4. Botrytis
  • 4. a. Identification
  • 4. b. Prevention
  • 4. c. Treatment
  • 5. Powdery mildew
  • 5. a. Identification
  • 5. b. Prevention
  • 5. c. Treatment
  • 6. Root rot
  • 6. a. Identification
  • 6. b. Treatment
  • 7. Health concerns relating to moldy cannabis
  • 8. The best mold-resistant cannabis strains
  • 9. In conclusion

If you want to have a smooth growth cycle without any headaches, it’s essential you do everything you can to avoid moldy weed. From checking and adjusting the growing conditions to applying fungicides as prevention. Mold can happen during veg, flower, and even after harvest, making buds unsafe to smoke, infecting surrounding plants, and even killing them. So here’s everything you need to know about mold on cannabis plants, from identification to prevention, to treatment.

1. What Is Mold?

Mold is a fungus that grows in multicellular filaments (aka hyphae) and there are several different types of fungi species that grow from hyphae, resulting in a fuzzy appearance, almost always being white but sometimes grey in coloration, which is due to the mycelium (which is the mass that forms from a mass of hyphae).

The fluffy or dusty texture you often see not only in cannabis plants but in all types of plants and foods is caused by the spores formed at the ends of the hyphae, and these spores are what you see when your plant has been infected with mold.

Dealing with mold on cannabis is a grower’s nightmare because the spores are so light that even a light breeze can carry them from one plant to the other, contaminating your whole crop in just a couple of days or hours. As mentioned, mold refers to several fungi species but, when talking about cannabis, there are a couple that you should be aware of, they’re:

Common Types Of Mold In Cannabis
Known as Scientific name Affects
Bud Rot Botrytis cinerea Buds
Root Rot Fusarium oxysporum Roots
Powdery Mildew Golovinomyces orontii Leaves

There are several ways to treat and prevent these types of mold but the best way is to maintain good growing conditions. These conditions will vary according to the stage your plant is in, this is why it’s highly recommended to have a thermo hygrometer to keep an eye on the humidity levels and temperature. So, what conditions should you keep to avoid mold?

2. Ideal Conditions To Prevent Mold

Checking and adjusting the growing conditions is the best way to prevent mold in your grow space, this may be hard to do without the right equipment. If you don’t have the equipment needed, there’s no need to worry, as long as your growing conditions are as close as possible to 20-24°C and 55-60% relative humidity, there shouldn’t be a problem. Now, growing outside of the ranges mentioned doesn’t mean that your plants will get mold but it’s a guideline to know where the growing conditions should be, approximately.

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Apart from the growing conditions, here are a couple of tips that will help you achieve the ideal growing conditions.

Tips To Prevent Mold Indoors
  • Oscillating fans help circulate the air, preventing air from becoming stagnant and reducing the chances of mold spores landing on your plants.
  • If you’re having trouble maintaining the humidity levels within range, make sure you buy a dehumidifier!
  • Keep your grow room clean! Cleaning up dead leaves and other waste reduces the possibility of fungi growing around your plants.
  • Having an exhaust fan allows air exchange, removing mold spores if there are any.
Tips To Prevent Mold Outdoors
  • A greenhouse provides an enclosed environment, giving you the ability to control the growing conditions with fans and heaters.
  • Grow strains with high resistance to pests and mold, this will allow you to identify and deal with mold before it’s too late.
  • Grow in pots because this allows you to move the plants around if you’re expecting bad weather.
  • If you’re growing directly in the ground, cover your plants with a plastic sheet to protect them from heavy rain.
  • Mold loves humid conditions so place your plants where they get as much sunlight as possible.

3. Mold On Cannabis

It is possible to get mold at any stage of the growing cycle, even in the drying and curing process. This is because fungi need a specific condition to develop. Mold is a fungus that can affect cannabis plants when they’re kept in humid and warm conditions. It can be treated with fungicides or other homemade remedies and can be prevented by controlling the environment but because it rots the leaves, roots, or buds it can be untreatable or very hard to treat.

Also, mold produces spores (and there’s a good amount of spores in the air anywhere you go). Mold spores can stick on your clothes and can be brought into your growing room. They need only humidity and a slightly warmer condition to start developing. We recommend keeping a clean growing environment, even if you never got mold or fungi, it is a great way to prevent it.

4. Botrytis

Botrytis (also known as bud rot or grey mold) is a type of fungus that affects plants in general. In cannabis, it develops inside the buds and slowly starts to grow outwards, making it difficult to spot in the early stages. So if you were wondering what does mold look line on weed, here’s an example.

Bud rot is easier to get when growing outdoors but can affect indoor growers if the temperature and humidity are not controlled. It can also happen when drying and when curing. If the buds haven’t dried properly they can still hold water, increasing the humidity in the curing jar and ultimately developing mold.


If you can’t see signs of mold but you notice the leaves drying or if you think the buds are not growing properly it can be a fungus starting to develop in your buds.

It’s really hard to detect bud rot in the early stages because the fungus starts infecting your plant from the inside out.

If you spot any of these symptoms, you should try to take a look inside the buds. The inside of the buds should be the same color as the outside, if you see brown or grey spots, it will most likely be bud rot.


This kind of fungus develops in humid and warm places, to avoid this, it’s crucial to have a good growing space. This means you need to provide good airflow, adjust the humidity level for each growth stage, avoid aggressive temperature changes, and keep your growing space clean.

For your drying room, in order to prevent bud rot, it is recommended to have a relative humidity of 60% and a temperature of around 20-25°C. This can be achieved not only by controlling the environment but also by pruning or performing LST techniques to keep the branches spaced. By having these elements on point, you can guarantee a healthy plant all throughout the growing cycle.


If your buds are heavily affected you can still treat them, although you should know that this is a way of allowing the plant to finish the growing cycle and it will not get rid of bud rot. The general recommendation is to dispose of the moldy plant to avoid contaminating the other plants in your grow room.

If you still want to save the infected plant, you should start by decreasing the humidity level and temperature, this will cause the mold to grow slowly. After doing this, you’ll need to spray the affected buds with a mold spray. If you see the mold continue to grow, your buds will get mushy and completely gray. At this point, you should remove the buds and if it’s really bad you should consider removing it from the growing space or disposing of it.

Have in mind that the affected buds can be toxic and should not be smoked!

5. Powdery Mildew

Powdery mildew is a kind of fungus that develops on top of the leaves at first. It may look like trichomes to the new growers but it will continue to spread all over your plant.

This fungus is a white powder that can completely cover your plant, especially the leaves, not allowing your plant to perform photosynthesis and ultimately dying it from the lack of energy.

Just like bud rot, powdery mildew produces spores that can easily spread indoors and outdoors and need very specific conditions to develop.


When powdery mildew first starts growing, it can be hard to spot it. You may see small bumps on the leaves, but because they are so subtle, you’ll most likely know you got powdery mildew when white powder starts appearing on your leaves.

The white powder will start covering the leaves until they’re unable to absorb light, if it gets to this point, the leaves will wrinkle up, start yellowing, brown, and die. Powdery mildew starts growing slowly but it can completely take over your plant real fast, so if you fail to spot it before, be sure to take action as soon as you see the leaves starting to be covered by a white powder.


As said above, fungi grow in very specific conditions, so the best way to prevent it is to maintain a good growing environment. This combined with minimal pruning or LST techniques will effectively prevent it. Growers who foliar feed should be especially careful, leaving drops of water on top of the leaves can easily cause powdery mildew.

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Powdery mildew can be a little bit easier to treat. First of all, you should adjust the temperature and humidity in your growing space, and remove affected plants from it. You should also check the other plants, as spores can easily spread to all the plants around. If your plant’s condition is too grave, you should start by removing the affected leaves and buds, and spray with any fungicide of your choice.

Remember, anything you spray on your plant will affect the smell, flavor, and quality of the buds, so you should opt for organic products or even try making your own at home.

Mix 35ml of apple cider vinegar to 1L of water or mix 400ml with 600ml of milk and spray your plant to treat powdery mildew. Have in mind these methods can fail sometimes and are usually recommended if the fungi infection is in its early stages.

6. Root Rot

Root rot is similar to bud rot, although it happens on the roots. This happens in soil when you get fungus gnats or when you overwater for a long time but it is more common in hydroponic setups.

Root rot is also hard to spot when growing in soil because the roots aren’t visible. Even experienced growers might notice it only when the plant can no longer be saved.


Root rot is easy to identify, as bud rot, you will see the roots start to turn brown and mushy. Have in mind that you will only see the roots if you completely remove your plant from the soil.

When the roots start rotting, your plant will start showing (what looks like) symptoms of overwatering, deficiencies, curling of leaves, or other symptoms that may confuse you into thinking it is something else. Prevention To prevent this fungus, you should not only keep a good growing environment but also make sure to not overwater your plants, as this can attract bugs like fungus gnats and also drown your roots, causing root rot.


Root rot is something that’s not treated in most cases because it will certainly affect your plants’ growth, so when growing in soil most growers will dispose of the plant. It is commonly agreed that a plant with severe root rot is not worth it because the roots will not recover to 100%. If you still want to treat it you can clean the roots with a mix of 5-10ml of baking soda or 10ml of bleach with 1L of water.

7. Health Concerns Relating to Moldy Cannabis

Cannabis that has been contaminated with mold should never be consumed, no matter how bad the contamination levels, the type of mold, and the method of consumption (smoking, vaping, edibles, extracts). This is especially important for users who suffer from acute respiratory symptoms, and those with weak or compromised immune systems. Cannabis users that are immunocompromised can be at risk of becoming seriously ill when ingesting moldy weed. There have even been recorded cases of hospitalizations, although no deaths have been attributed to moldy cannabis ingestion. According to certain studies, up to 20% of cannabis samples purchased in dispensaries throughout California in 2019 had some form of fungal or bacterial issues. Dispensaries are a controlled market, so let’s not even begin to think about how high that number may be on the black market. This widespread mold issue was less of an issue before the introduction of large-scale cannabis farming and is a problem that has been on the rise since legalization started (in the US anyway). As most hobby growers can attest to, it can be difficult to control mold issues with even a small grow, let alone a farm containing thousands of plants. Maintaining a clean and sterile environment for your plants to grow is harder the larger the scale of the operation, as is environmental control.

The more plants you have, the more difficult it is to control airflow, humidity, and the correct temperature range. This is one of the best reasons to consider growing your own plants, as you can have total control over the process – from seed germination to harvest, and then through the drying and curing process. If you suffer from asthma or other respiratory issues, then you are at a higher risk than the rest of the population. Always check for visual signs of mold before consuming any cannabis. Some of the possible adverse health reactions that could arise from consuming mold-infected weed are

  • Allergic reactions, ranging from mild to severe
  • Chest pain
  • Wheezing
  • Shortness of breath
  • Heavy coughing
  • Irritated eyes
  • Loss of memory
  • Low energy levels
  • Fever

If you think you have smoked, vaped, or eaten moldy weed there are a few things you should do. If you have any of the possibly compromised weed left, check it thoroughly for signs of fungal growth. Don’t panic, as for the large majority of us, there is nothing to be hugely concerned about. If you think you are having an adverse reaction to moldy cannabis, it may be best to consult a health professional. Unless you have acute upper respiratory symptoms there is no need to run off to the ER, but take note of how you are feeling and contact a doctor if you feel the symptoms are worsening.

8. The Best Mold-Resistant Cannabis Strains

Here at FastBuds, we have always focused heavily on ensuring our entire range of seeds and strains comes with a high degree of mold resistance. Autoflowering strains, for the most part, come with a high amount of natural resistance to mold. This is thanks to the Ruderalis heritage that all auto-flowering strains share. Cannabis Ruderalis is subspecies of Cannabis Sativa and has some interesting and unique properties including a high amount of inherent fungal and pest resistance. The name “Ruderalis” is derived from the German word “ruderal” – which was a widespread term to describe roadside weeds. This outdoor heritage ensures that auto-flowering cannabis plants, as a whole, have strong natural mold immunity. But, that doesn’t mean there aren’t certain strains that are known to be better mold fighters than others.

9. In Conclusion

It is relatively hard to get a fungus to affect your plants if you are keeping them in a good environment but it’s essential you know how to tell if your weed has mold. Maintaining a good environment may seem easy to most growers but can be extremely hard for new growers, especially in countries where it’s hard to find growing equipment. If you’re tired of your plants getting mold, we recommend trying more resilient strain, like our Gorilla Cookies Auto.

I got 134g off this gal growing in 3 gal pot with 24 hours of light. i’m stoked with the result! Smells like diesel. Was a great grow overall.