Plant Growth Regulators Poison Marijuana

gore March 3, 2012 67
Plant Growth Regulators Poison Marijuana

Recently Rambo posted an article  titled 7 problems with tall marijuana plants where he mentioned plant growth regulators (PGR). Some of these chemicals are in fact poisonous and have been banned for use on food crops in most civilized countries. Despite the known dangers of these products they are still used under license by the USDA on ornamental crops. The use of these PGRs are visible in many ornamental species available at nursery and garden stores, explaining why you find Azaleas and Zinnias blooming at 3 inches tall.

Regulations for fertilizer labeling in the USA is strict but varies from state to state. Despite these regulations, formulators are not always required to list every ingredient in their products; these recipes are protected as “trade secrets”.  For this reason formulators have been allowed to market known toxins to unsuspecting farmers for some time. Fortunately a formal inquiry conducted by the California Department of Food and Agriculture (CDFA) has revealed the truth behind these insidious products. The CDFA tested several products, and the findings have since been made public, thanks, in part to the Freedom of Information Act. Below is a summary of the lab results, to view the full report simply click the product name.

(PDF Links will open in new window)
: 271ppm Paclobutrazol
Gravity: 516ppm Paclobutrazol
Flower Dragon : 18,400-18,650ppm Daminozide, 30-46.3ppm Paclobutrazol
TopLoad: 3,467ppm Daminozide
Phosphoload: 17,800ppm Daminozide, 20.6ppm Paclobutrazol
Recall Notice

So the secret is out.  These guys have been marketing poison to the marijuana growing community for years and have been getting away with it.  Lets take a look at some of the ridiculous claims and out right lies made by these not so reputable vendors.

Here is the sales pitch used by Emerald Triangle’s marketing department to sell their product called “Gravity”:

“Our uniquely prepared kelp extract and phosphorus based additive will harden your flowers from the top to the bottom. A little goes a long way. Use once or twice about 3 weeks before the end of a plant’s cycle. Adds size and weight to flowering plants.”

Thanks to the CDFA report, we now know that Gravity is in fact a PGR called Paclobutrazol. This chemical retards internode length and reduces maturation time significantly. When used on marijuana, this results in tighter flowering tops that can be harvested earlier. This has made Gravity an attractive fertilizer additive to many unsuspecting growers.

The makers of Phosphoload, Dutch Masters market their product with these out-right lies;

“Dutch Master PhosphoLoad utilizes a new technology which extracts unique isolates from coal derived humates. These are powerful earth elements that unlock the floodgates for a fast & powerful flowering response. When used, PhosphoLoad produces dramatically larger and heavier yields of flowers with an average yield increase of 25 to 30%.”

While Phosphoload may contain “powerful earth elements” it also includes; 17,800ppm Daminozide and 20.6ppm Paclobutrazol. These two dangerous chemicals are not approved for crops intended for human consumption, and should never be used for growing medicine.

Products known to contain Paclobutrazol and Daminozide have been banned for sale in California and Oregon but are still readily available through Internet distributors, and who knows how much is still in the hands of marijuana growers.  In truth this regional ban will have very little effect on the availability if these PGRs. The good news for users of medical cannabis is that companies now offer testing for these dangerous chemicals. SC Laboratory’s in Santa Cruz California is one of these companies currently testing PGR’s in medical marijuana.


IUPAC name: N-(Dimethylamino)succinamic acid
Molecular formula: C6N2H12O3
Commercial trade names: Alar, Kylar, B-NINE, DMASA, SADH, B 995
Consumer Products: Flower Dragon, Top Load, Phosphoload

Daminozide has been shown to promote early fruit set, blossom set, and enhance color in apples, tomatoes, grapes, stone fruit and ornamental plants.

Daminozide was approved for sale in the USA in 1963 and was popularized by apple farmers until 1989 when it was nearly banned by the FDA as a suspected carcinogen. At that time it’s manufacturer Uniroyal Chemical Company withdrew it from the market for use on food crops but continued to offer it for use on ornamental plants. That same year the television program 60 minutes featured a segment outlining concerns of the use of Daminozide and cancer causing apples. This created a terrified public that refused to buy apples resulting in a law suit filed by apple producers against CBS, NRDC and Fenton Communications for 100 million dollars in damages.

The Environmental Protection Agency (EPA) currently lists Daminozide as a probable human carcinogen. At present, further testing is required to clarify how dangerous it really is.


IUPAC name: (2S,3S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol
Molecular Formula: C15H20ClN3O
Commercial Trade names: Cultar, Astar, Bonzi, Clipper, Holdfost, Klipper, MET, Parlay, PP333
Consumer products: Bushmaster, Gravity, Phosphoload, Flower Dragon

Paclobutrazol retards plant growth by inhibiting the plants natural production of natural growth hormones called Gibberellins. This results in shorter internode length, greater root development, early fruit set, enhanced fruit set, and a reduction in frost sensitivity. Paclobutrazol is also marketed as a fungicide

Paclobutrazol is banned in most European countries while the US EPA lists it as “Moderately Hazardous” and states, “This substance has not undergone a complete evaluation and determination under US EPA’s IRIS program for evidence of human carcinogenic potential”. At this time it appears that Paclobutrazol has not been banned but has no food use registrations in the USA.

I encourage readers to investigate the use of PGRs in greater detail. It’s important to understand that these chemicals dramatically alter the natural behaviour of plants. PGR’s in comparable doses used different plant species can have very different effects. The exact biology of some of these complex hormone-like interactions is still under study. It’s possible that we will never fully understand the effects of PGRs on produce intended for consumption via combustion.

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Plant Growth Regulators Poison Marijuana , 4.2 out of 5 based on 23 ratings



  1. 45YrToker March 5, 2012 at 5:11 pm -

    Just a word about Gibberellins. As mentioned, this is a naturally occurring growth hormone in most plants, but, it is also produced for use in agriculture as Gibberellic Acid, most commonly being used on Thompson Seedless Grapes. It is another substance that some breeders use to induce male flowers on female plants to produce female seed. As a farmer, I have access to it from my CA PCA, and I’m sitting on a gallon at 40,000 PPM. That’s more than I could use for producing fem seed in the rest of my life. If any of you are interested in producing fem seed, get ahold of me, and we can make a far better deal than people are getting from the usual sources, like selling it for $40.00 for 10 grams. I paid not much more for the whole gallon. And don’t be fooled by MegaGro saying that they are Gib. It has Gib in it, but it won’t work for fem seed. It’s just a soil, or foliar, amendment. Spraying Gib on plants at a lower ppm will cause them to elongate & stretch, and some people use it that way, as well, to gain size before flowering. But, inside or out, tall plants are a huge pain in the butt!

  2. Daniel May 10, 2012 at 9:55 pm -

    you fail to mention that if you flush the Cannabis properly before harvest it rid’s it from its toxins, very much so like humans detoxing from alcohol ciggerattes, instantaneous, i understand where growers are coming from when they condemn the use of them but they are a very effective tool which i think the majority of modern day growers use

    • gore July 19, 2012 at 7:58 pm -

      @Daniel’s comment
      Almost a month later I read this and i feel like it warrants a comment form me.

      “I think the majority of modern day growers use (PGR’s)

      Do not be fooled by Daniels attempt to justify his use of PGR’s by basically saying “well everyone else is doing it”. This faulty reasoning is one the of leading contributors of all evil committed daily throughout the world. In rebuttal to this comment I would continue to urge readers to avoid use of any products they suspect may contain PGR’s, Also I would like to add that I know a lot of growers, a lot, maybe more than Daniel does, and NONE of them still use these products.

      This argument is so foolish I was tempted to censor it. Garbage logic.

    • drew January 25, 2013 at 2:18 am -

      Growth hormones perspire through the buds as do synthetic nutrients.. Once they go through they never leave. I definetly don’t want to try any of your fruits. You talk confidently though the fact is you know nothing about a plants chemistry.

  3. Rambo May 10, 2012 at 11:09 pm -

    Daniel, Toxins don’t flush out of plants, neither do fertilizers. That is not how it works. Plants store fertilizers in their leaves so they can draw from it when needed. When you “Flush” with water in the week or two prior to harvest you are not flushing out toxins, you are simply depriving the plant of nutrients in the water so the plant instead burns its stored nutrients already in the plant. Plant growth regulators are not the same as fertilizer. They don’t flush out with water.

    Think about it like this. You may be able to burn fat by not eating. Plant growth regulators cause plant mutations. Just like a weightlifter on steroids, the effects may ware off after some time but the toxins remain. A week or two of drinking lots of water does not make steroids safe. Using PGR’s on cannabis is also not safe. That is why PRR’s are banned in the United States for use on crops meant for human consumption. PGR’s are toxic, carcinogenic and completely unnecessary for growing huge amounts of top grade cannabis. If you can provide peer reviewed scientific research to back up your statement, I would love to see it.

    • j April 10, 2014 at 2:15 am -

      You really don’t know anything about chemistry do you. Stick to the weed because you have no place making claims about “toxins” and there effects on plants. Once more you got your steroid comparison way off. Steroids don’t stay in the human body for ever. Some are completely gone in days. Most are gone within a few months and just about any known to man are totally untraceable affter 18months. You almost got that exactly backwards.” The effects wear off but the toxins stay”. Not even close. And also steroids are not toxins. They’re hormones. But if you want to take a simplistic uninformed view that anything that’s “bad for you ” is toxic go for it. But try to keep science out of your irrational argument.

    • Mario Jaurigue May 7, 2014 at 6:50 pm -

      Have you heard of people getting sick or know what possible symptoms might indicate that you have ran into such products in your marijuana ? I am concerned about my wife catcting a pneumonia which has put her in the hospital and I suspect it was something in the weed. It smells,tastes,smokes ,and looks weird. Please reply if you can . I need a little help to figure this out.

  4. Gore May 31, 2012 at 11:18 pm -

    It’s possible that Advanced Nutrients “Bud Ignitor” should be added to the list above. I will update the article If and when there is sufficient evidence to support this. In the mean time I suggest use of this product be discontinued for marijuana production.

  5. Kent b June 19, 2012 at 12:48 pm -

    What do you know and thing about Ed Eosenthal’s Zero Tolerance? Thank you.

    • Rambo June 20, 2012 at 9:57 pm -

      Well I don’t have a bottle of it in front of me but I have tried the pesticide in the past. If I recall is was made from plant oil extracts. I am pretty certain that it is all natural and possibly organic, either way I would consider it safe to use on your plants. Sense you are asking this questions on an article about PGR’s I guess I should mention that it does not contain any.

  6. gore July 19, 2012 at 8:02 pm -

    NAA, IBA, and gib are all PGR’s. The industry is begging to condemn these as well, does anyone have any source info indicating these as posing human health risks?

  7. thepfli August 6, 2012 at 12:16 pm -

    It’s rather amazing how much misinformation is floating around about Paclobutrazol- especially when it’s easy enough to Google the facts.
    Paclobutrazol is not banned anywhere in the world. Paclo and Gibberellic acid are the 2 most common PGR’s used on food crops in the world. And we’re not talking about 3 rd. world countries where anything goes. Over 75% of the apples in the UK are sprayed with the above combo. We’re talking millions and millions of pounds. Most of the commercial cherry orchards in Spain use Paclo to dwarf the trees and increase the size of the fruit (sound familiar). Spain, by the way is a major cherry producer in Europe. The regulations governing PGR’s on food crops in Europe are as stringent as they are here. Japan has the most stringent regulations in the world when it comes to spraying pesticides and growth regulators on food crops. Paclo is used extensively there on both apples and pears. The same goes for Australia. In spite of extensive testing and retesting over the past 25 years, Paclobutrazol has never been found to be carcinogenic or a suspect carcinogen, nor does it break chromosomes.
    Is Paclo safe? The above info is all verifiable fact. Decide for yourself

    • Rambo August 6, 2012 at 1:37 pm -

      I’m sorry, that’s not how this works. If you are going to call us out you have to provide the sources. You can’t just spew misinformation and then tell people to google it. You have to provide your sources.
      I’m not sure where in the article you read that Paclobutrazol was banned. It’s not banned, it;s banned for use on food crops. As far as Gibberellic Acid goes, that wasn’t mentioned in the article as being a dangerous plant growth regulator.
      Paclobutrazol is not for use on food crops and has no food use registrations. I called the guys over an Syngenta who make Bonzi and another PGR product for turf which both contain Paclobutrazol. I asked if there were any allowable uses on food crops and the response was a 100% absolutely not. Here is the labeling info from the EPA as well as a lot of other research on Paclobutrazol.
      Here is the chemical data from the EPA
      I’m going to do you one better. I just emailed Tony Kish at the EPA who is in the Registration Division for PGR’s I will post his response in the comments when it comes back.

      • j April 10, 2014 at 2:00 am -

        One of your links goes nowhere. And the other is warning labels with no info what so ever about the actual claim your making. If you’re going to require facts from guests comments then you should probably get some yourself. You have provided no scientific evidence to support your claim.

    • gore August 7, 2012 at 9:54 am -


      If you have information that is contrary to what we have printed we are very interested. The above article was the collimation of many hours of research, telephone interviews, and first hand experience. It’s important to us that the information we provide is accurate.

      If what you claim is true the article will require an addendum, but you’ve offered no source material.

  8. Joe Bob August 14, 2012 at 9:39 pm -

    The main reason there are strict regulations on PGRs is not because of overwhelming scientific data pointing at harm. The regulations stem from a scare campaign in 1989 from a 60 Minutes episode.

    Bruce Ames of the Ames Test spoke out against this arbitrary fearmongering resulting in banning what was by all accounts a growth regulator that was not poisoning anyone. Political activists–although they loved Ames for discovering a way to detect carcinogens–didn’t agree and pressed on anyway. They do the same thing today with spooky stories of power lines giving people cancer.

    The real story is unscrupulous marketing of simple PGRs. Many nutrient suppliers do the same thing with an array of brightly colored snake oil products when plants can thrive just as well on any properly formulated fertilizer. Cannabis-focused fertilizers are all a little bogus considering it is a foliage-dense weed and all it needs is balanced continuous fertilization. Of course, cannabis growers will buy anything and have money to buy it which is exactly why these companies hid the formulation.

    I once saw a product called “Dr. Node’s” state it contained paclobutrazol in a hydroponic store. That doesn’t seem nearly as dishonest. (It was still overpriced for raw paclobutrazol formula).

  9. The Gardener August 16, 2012 at 11:49 am -

    I have been gardening since 1970. I have grown this particular plant starting then as well as many other food and non food (ornamental) crops over the years. I have worked in the horticultural industry most of my life and am for the most part now retired except for my pet/exotic plants that I will never tire from growing. With that being said, I have worked with PGR’s while I was in the nursery industry growing ornamentals and also on turf in steep and hard to navigate areas where maintenance was required. They were marketed as the PGR’s that they were and it was very clear that they were not to be used on food crops. I find it very troubling that the big 3 hydroponic distributors (Sunlight Supply, BWGS, and Hydrofarm) are allowing certain products to be sold and distributed nation wide (even from California) with some of these PGR’s present in the products. It is wrong in so many ways. The only way to truly stop this is a nation wide protest against these companies and the distributors demanding that they only market safe fertilizers and supplements. There are apparently many growers that are ignorant as to the health and safety concerns surrounding PGR’s and that they are even using them as they are not listed on the ingredient labels. It is also a shame that the US-EPA has not done any more testing to find out definitively the dangers that these PGR’s pose to the consumers of cannabis or any other food product that they are secretly being used on. I do not live in California but I visited a local hydroponics store yesterday and talked with the manager that was completely aware of the PGR’s that were in Bushmaster that he was selling and basically laughed it off and said “So what?”. He then tried to sell it to me. Even though California has quarantined those five or so products containing PGR’s, not to be distributed, BWGS and probably the other two companies are continuing to sell to retailers in other states. The DEC in my state isn’t too concerned in doing any testing because it is expensive to test for these compounds and who cares about cannabis growers and consumers anyway. I truly do not know what to say. PGR’s should in my opinion be considered dangerous until further testing by the EPA is done. As far as Bud Ignitor is concerned, I have been in contact with Advanced Nutrients and was told that it does not contain PGR’s, and it has been tested.
    However they have not been forthcoming as to providing a copy of the test results and who did the testing. Maybe if more people wrote to Advanced Nutrients they would see how serious and concerned the growers were with the safety of the nutrients and supplements being sold under their name. In fact we should all start a write in blitz to the big three distributors with the same requests. OK I am now off of my soap box.

    P.S. You show one picture of Big Slugger’s garden in now time but no video as yet. What is with that?

    We can all grow large plants with large and beautiful buds without the use of PGR’s. Happy gardening!

    The Gardener

  10. mike September 29, 2012 at 6:15 pm -

    A bunch of fear mongering leftie liberals, spouting off BS. I use Gravity and crush it!

    • gore September 29, 2012 at 8:02 pm -

      Liberal fear mongering is a plague, I agree. However I feel that it is our obligation to report on the controversy surrounding PGRs and their use. Furthermore, after researching the topic, I feel there is very good reason to avoid these additives.

      • Rambo November 11, 2012 at 10:49 am -

        Here is another article which contains a longer list of products containing PGR’s.

        @ Mike, The only thing you are crushing is your reputation. Sure PGR’s work great but so does DDT. That doesn’t mean that sick people with already compromised immune systems or anyone else for that matter should be consuming it. You’re comment underlines what is wrong with this industry. The get rich quick, at all cost mentality, with no concern for the safety of the end user is disgraceful and all to common.

    • eric juell March 3, 2014 at 8:33 pm -

      Why can’t we just leave nature alone. I too have broken out in blisters on my hands and head. Bad itching sores, as soon as I stopped smoking the contaminated growth regulator weed blisters gone .
      Growers do it to bulk the plant, in essance to make more money. The whole idea of brothers getting high is crushed. Money is more important than anything anymore.
      Growers get a grip, do the right thing because it is the right thing to do.Poisoning your feliow head does not make you a great person.
      Greed based system go to hell.

  11. Old Guy December 23, 2012 at 10:00 am -

    While doing PGR research on growing watermelons I stumbled on the unavoidable bio eco pot growing chatter. I used to smoke some pot back in seventies, but gave it up because it simply makes me tired. Plus it was downright hard on my lungs. That was back when a Kilo of good Mexican stuff half full of stems cost about 100-150 bucks on the other side of the border.

    I find it interesting that most of the posts worry over the chemicals and carcinogens they are putting in their lungs. I might suggest that Marijuana smoke is highly carcinogenic and far worse than cigarette smoke so I really don’t get the point. I gather that smoking pot helps those with cancer which is probably what they got from smoking too much anyway. The bottom line is that all that PGR hoopla is over the self sustainable business of selling a highly carcinogenic substance in the first place.

    I like to garden and the odd year I still grow a few pot plants just for fun which is probably not a good idea. I grew ten bushy fat 8-10 ft tall plants (outside) last year without using any PGR’s. Instead of just cutting them down and burning them, this time I gave them away to my neighbor. I have no idea what he was going to do with all that pot. I guess the yield would be about 8-10 lbs of dry bud. One thing I noted was that when plants get that big it takes little rain and wind to break down 4-6 ft branches.

    Interestingly DDT saved untold millions of lives world wide before it was banned . . . The product was basically used to kill mosquitoes carrying yellow fever and malaria.

    Now back to my nerdy watermelon research 🙂

    • Rambo December 27, 2012 at 10:08 am -

      Always interesting to see comments from those that are not fans of cannabis. Thanks for your contribution. I do have a few observations. I would be willing to bet that the pot you smoked was hard on your lungs and throat largely because of the quality of the Mexican weed you used to smoke. Improvements in quality and growing technique has made it possible for patients and recreational users to smoke much less cannabis to get the same if not better results. Additionally, vaporizers have made it possible to eliminate most if not all carcinogens from the cannabis. Some cannabinoids like CBD have actually been found to have anti cancer properties in laboratories studies, though I would agree the smoking cheap mexican weed probably does more harm then good to most people. I think it is a rather large leap, and actually downright insulting to suggest that the people who use cannabis to treat the symptoms of cancer and chemo got that cancer from smoking pot. I personally know many individuals who never used cannabis for recreation but have found it very useful for treating the side effects of chemotherapy. While I agree that DDT was an effective poison for killing mosquitoes, it was still a poison and I doubt that cancer patients would want to find it in their cannabis either.

  12. home slice February 11, 2013 at 10:38 am -

    What is the difference between GMO and PGR’s. And why is the US government okay with genetically modified organisms and not plant growth regulators?

    • Rambo February 18, 2013 at 8:02 pm -

      GMO’s are genetically modified species designed in a lab to exhibit a trait that is considered desirable like resistance to round up. PGR’s are chemically that are fed to the plants that make them exhibit abnormal growth pasterns considered desirable.

  13. Lisa Perceval March 19, 2013 at 1:57 pm -

    Uncertainty is bad, but risks can be assessed and quantified. It doesn’t seem like anyone has applied the existing metrics to the case of the safety of using paclobutrazol in the cultivation of cannabis.
    The EPA (ref. CASRN 76738-62-0) has established the oral Reference Dose (RfD) of paclobutrazol to be 1.3-2 mg./kg. per day. This is the amount of PBZ that is is likely to be without an appreciable risk of deleterious effects during a lifetime. The uncertainly factor in the EPA’s assessment is very high— a factor of 1000, due to the brevity of the study and lack of interspecies data.
    A typical case study of PBZ use in cannabis would be the current standard for Bushmaster. In a hydroponic setting, 1 ml of Bushmaster per gallon of nutrient solution is used for daily feedings for three to four days. For a single grow tray that produces one kilogram or more of cannabis, this would typically involve no more than 40 gallons of nutrient solution. Since Bushmaster contains 271 ppm of PBZ, this would amount to 10.84 mgs. Erring as far as possible on the side of safety, we could assume that every speck of PBZ is going to not only persist, but end up in the buds of the plant. It would therefore be necessary for an individual to consume 119.92gm/kg. per day of cannabis to be at the low end of the RfD. The average North American weighs 80.7 kg (incredible, but true), and hence would have to consume 9677 grams of cannabis to hit that low threshold. Even applying the quasi-apocalyptic uncertainty factor, the average North American would be perfectly safe from the effects of PBZ whilst consuming almost ten grams a day of cannabis. Those consuming more represent, I believe, an outlying fractional percentile of cannabis users, whose health problems are probably far more pressing than trace amount of PBZ in their product.
    That being said, it is illegal according to Federal Law for items for human consumption to contain PBZ. As is the production, sale, and consumption of cannabis.

    • Rambo March 25, 2013 at 8:54 pm -

      Interesting take on the subject. I tend to agree that a little probably won’t hurt you. That goes for a lot of things. I however try my hardest to avoid getting gasoline in my mouth when siphoning from a tank. Same goes for other chemicals I know are probably not good for me.

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  15. Bigbux May 14, 2013 at 12:42 pm -

    I recently used .4ml/gal in a 50gal. undercurrent system on a medical cannabis crop under 4KW of HID light. It turned beautifully vibrant and healthy ladies into some very sickly ladies. I think there may have been other factors, but I got the ‘dragon claw’ on almost every secondary leaf and it simply got worse until I flushed a few days later. The plants look to be very stunted as far as flower production goes and I’m now hoping for 20% of what I was originally counting on. I was running between 700 and 800 ppms at the time. It’s hard to say if I had other problems that contributed or Bushmaster exacerbated, but I have to tell you that tears have been shed over what looks to be a huge loss with BM as the main suspect.

    Also wanted to say that I appreciate this article/blog very much and definitely takes the typical cannabis forum discussion to a higher level. This information is all very valuable, but also props to Lisa for breaking down the numbers which can never never be ignored when analyzing this situation. Saying, “this product contains a PGR” sounds a lot different than “you need to smoke 20 pounds a day to hit minimally significant levels, assuming the plant kept and stored every molecule you fed it”. Good shit Lisa. Anyways,…awesome discussion…

  16. wayupnya June 7, 2013 at 4:33 pm -

    hey man enjoy the bud. dont smoke if ur concerned but please always enjoy. pleanty to pick from true budsmen havent a worry nor should u

  17. Steven Linder June 20, 2013 at 7:10 pm -

    There’s more in Cannabis than anyone has ever thought of. Cannabis may hyper accumulate heavy metals found
    in contaminated soils and especially Cadmium from Kelp and rock phosphate based “Organic” fertilizers.

    But, that’s just the tip of the shit pile.

    3-chloropropane diol, an artifact of acid hydrolysis of fish waste and soy, is potentially a potent carcinogen present in those “Organic” product.

    The best one is the excessive chloride ion present
    from fish waste and kelp accumulates in Cannabis,
    and when smoked, creates Dioxins, with long term
    health consequences.

    Clean it up.

    There’s no real medicine until it’ is.

    • Bongsao October 15, 2013 at 8:59 pm -


  18. Steven Linder June 22, 2013 at 2:54 pm -

    I’m steven.

    I’m sorry for the haphazard shape of my comments.

    I’ll try do do better in the future.

    BTW. Daminozide hydrolyzes to Hydrazine orally.

    As I’m 64, most people I know that have used

    “Organic” only based feeds for Cannabis, suffer

    from premature aging effects of the entrained

    pro-toxins. Where are the peer reviewers?

  19. dave July 29, 2013 at 5:07 pm -

    i respect every growers opinion, but you all forget your medication you grow is for you, not for you to sell. so if one man wants to use gravity and takes the chance of getting cancer… more power to him.its a tru gardeners responsibility to serve the information and let mankind choose his ways. half you people are prob growing and selling your medication to your local co ops. wich is aginst the law. and half the co ops dont give a shit about whats in there product as long as thay can sell again the info is out there you as a man make the choice if you want to put that in your body..but dont let some smuck on the internet try to feed you his perspective of what should be done. no one is ever gunna shut these mass producers down..peace love and great growing to all

    • Rambo July 31, 2013 at 7:21 pm -

      Your statement assumes that everyone who uses medical cannabis is well enough to grow their own. This is a pretty big assumption.

  20. Aces August 11, 2013 at 7:47 am -

    Just curious if your research has led you to believe or find out if the AN Ph Perfect line has PGR’s or if Cyco *the american brand* has any at all either. Thanks

  21. Dan September 19, 2013 at 1:53 pm -

    Title is very misleading — not ALL PGRs are harmful. Either list the specific ones in the title or change the title to “Some” Plant Growth Regulators Poison Marijuana.

    Otherwise you’re no different than all those “unscrupulous” nutrient companies……

  22. Jarkko October 8, 2013 at 4:13 pm -

    Thanks to this great article : I just found out they put this stuff on wheat crops on europe. Not paclobutrazol but same kind of shit that stops the plant growth and hormone production. : CCC

    So its in my bread.

    I wouldnt like to be the one selling weed to cancer patient and saying : hey i just put the cause of your cancer to your weed too.

    Now this stuff im talking about has not been linked as carcinogen but some dude took a sip and died. Also has been found out to propably cause liver damage and stomach problems. Also not sure if the studies are paid , figure this out for yourself.

    Man this business of poisoning people is getting (or at least is) fuckd up.

    Additional info:
    -Its not allowed for animal digestion yet it is for human , baby foodbatch was contaminated but Nestle says its ok coz its allowed… , blabla i found a lot on the subject. Ones that really stick out are the people that are getting sick of wheat. My mom is like that and some suggest its because of these additives.

  23. Craig October 16, 2013 at 10:41 am -

    I was turned over to BushLoad as an alternative to Gravity, but I was not very impressed from my last crop using it. For my next harvest I was turned onto Golden Tree by humboldts secret from a friend who vouched for it highly. Glad I used it because it was way better.

  24. glenn January 5, 2014 at 12:29 am -

    @dan… your point Dan? Are you saying, people who don’t indulge in purposeful language semantics are way way worse than someone maybe poisoning you with an suspected dodgy… health wise product!!!
    Whatever the word…”Some or all” I ain’t pushing my luck.
    Who you work for Dan?

  25. R.v January 23, 2014 at 5:21 am -

    from smoking cannabis containing chemicals i have come out in blisters on my cheek,nose and chin.i got told it had been flushed but as soon as i blazed one up i could taste it.. i know its from chemicals due to the fact for the last 2 month i have been smoking some really good blueberry..but it ran out so i had to get some diferent stuff,when i woke up the next day boom the blisters had arrived.

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  29. Nate July 16, 2014 at 1:32 pm -

    Great discussion, it’s nice to see an attempt at scientific rationality. I think the real issues here are greed/commercialism and, what I call “the Emperor’s New Clothes Syndrome.” The two are connected. As legalization advances growing and sales become increasingly commercial and small growers are forced out. The industry promotes a false ideal of how marijuana should appear which is the basis for the consumer’s purchasing decision. This leads growers to use any means to achieve that “look.” Hence the use of hardeners and various other additives. My many years of observation, as well as conversations with numerous people in this industry, lead me to the conclusion that appearance tells nothing definitively about potency, which is the real issue.

  30. ItsAboutResearchDoSome July 24, 2014 at 5:44 pm -

    Ok there is a huge layer of conjecture about the use of Paclobutrazol and its totally understandable considering the hysteria out there. It is not true to say it was banned in any country the illegal sale of products containing it without proper registration has been banned the same thing has occurred to some brands of NPK fertilizers. It is registered for use on food in many countries New Zealand, Australia (, Kenya, Mexico and may others and for good reason it is only mildy toxic to animals ( It is also registered for use on Rapeseed in the EU. It has a degradation curve arcing out in 25-45 days. That means it degrades almost completely within 25-45 days this means that a mild root application of dilute 100:1 H2O: PBZ from a 25% a quality Suspended Concentrate (Cultar or Austar) can be used to arrest gibberllin production force bud growth and if skillfully washed will leave no detectable trace to the Limit of Detection which is a very tiny amount. So tiny an amount of a mildy toxic chemical that it literally wouldn’t hurt a fruit fly. Not many people know this technique but they appear to be getting the best product and yields without polluting the product. This is all empirically tested fact I’ve got 10 years of scientific grade research experience on PGRs specifically the residual amount of a chemical permissible in food. This is called the MRL maximum residue limit this is entirely based on the risk consumption of the product poses to humans. Paclobutrazol has been tested continuously for 25 years and still has a low MRL to compare that with DDT it is massively illegal to poses it let alone apply it to food any comparison between the two is not at all accurate.

    • Rambo July 25, 2014 at 7:16 am -

      Great info and thank you for the contribution. I still believe PGR’s in this industry are probably a bad idea. Many growing marijuana are not professional horticulturalist or food producers and often don’t use the correct amounts of products. Additionally products that may be safe when digested may be reactive when ignited. I have so far seen no info about this since all the studies I have seen are only regarding it’s use on foods.