University of Guelph paper- Flushing is a myth!

[therevverend]

A recent blind taste test study conducted by RX Technologies

It's not a 'study' it's advertising. For their family of grow products. Here's a blurb from their website about the 'study'.

Cannabis variety Cherry Diesel (Cherry OG x Turbo Diesel) was grown at the Rx Green Technologies R&D Facility using Rx Green Technologies nutrients and Clean Coco. Grow A, Grow B and E-Plus were fed during the vegetative stage and Bloom A, Bloom B, E-Plus, and Bulk were fed during the flowering cycle. The first flushing period began 14 days before harvest. The other flushing periods were ten, seven, and zero days before harvest. Each flushing period was tested on 12 different Cherry Diesel plants divided into four different groups (replications) spread evenly across the flowering room tables. Flower and fan leaf samples were collected from each flushing treatment the first day of flush and the day before harvest to quantify concentrations of essential plant nutrients. After harvest, trial plants were cured before determining final trimmed flower weight, terpene and THC concentrations. Trim was evaluated by an extractor for THC, yield, and appearance of the extract or “wax”.

They're using their own blend of snake oil hydro chemical shit. They have pictures of the leaves of the plants. The leaves of the 'flushed' plants after 14 days are yellow and dead, because they killed the plants by not feeding them. They need you to buy their shit and keep pumping the plants with it until harvest so you spend more $. They also show pictures of the wax made from the trim. The flushed wax looks like shit, obviously the resin sat there under the lights for two weeks degrading. I wouldn't want to smoke it.

We could run our own study, pump some of my outdoor plants with their hydro shit right up until harvest. Versus my own plants that get organic P, K, and molasses until 3-4 weeks before harvest. We could also pump a couple plants with a cheap run-of-the-mill high concentrate non-organic PK mix until 2-4 weeks before harvest. I wonder which would be the better tasting product? I wonder if their hydro mixes would taste any better or yield any more then the off brand chemie PK? I'm guessing not and the non-organic off brand PK would yield well and be tasty. I also wonder how fucked up my soil would be next year or 5 years from now from running all the highly concentrated PK shit through it. I'll bet the weeds next spring wouldn't look the same!

 

[BongFu]

It's not a 'study' it's advertising. For their family of grow products. Here's a blurb from their website about the 'study'.



They're using their own blend of snake oil hydro chemical shit. They have pictures of the leaves of the plants. The leaves of the 'flushed' plants after 14 days are yellow and dead, because they killed the plants by not feeding them. They need you to buy their shit and keep pumping the plants with it until harvest so you spend more $. They also show pictures of the wax made from the trim. The flushed wax looks like shit, obviously the resin sat there under the lights for two weeks degrading. I wouldn't want to smoke it.

We could run our own study, pump some of my outdoor plants with their hydro shit right up until harvest. Versus my own plants that get organic P, K, and molasses until 3-4 weeks before harvest. We could also pump a couple plants with a cheap run-of-the-mill high concentrate non-organic PK mix until 2-4 weeks before harvest. I wonder which would be the better tasting product? I wonder if their hydro mixes would taste any better or yield any more then the off brand chemie PK? I'm guessing not and the non-organic off brand PK would yield well and be tasty. I also wonder how fucked up my soil would be next year or 5 years from now from running all the highly concentrated PK shit through it. I'll bet the weeds next spring wouldn't look the same!

Yawn and yet they confirmed what the Uni of Guelph study found - run water only for 14 days and there is no yield loss nor terpene and cannabinoid loss (nor gain). So they are saying don't use our nutrients for the last 14 days. You Flat Earthers sure do reach for some lame arguments. So conclusion is

Against Flushing
Q: Do you flush?
A: No, I run water only for 2-weeks to save on nutrient inputs.

For Flushing
Q: Do you flush?
A: Yes, I do, for two weeks. It makes the product taste “cleaner/better/less chemically” etc.

 

[mexweed]

lots of weed seems smooth if you only take a few tokes of it, how does the smoothness hold up smoking an oz a week, how do the last couple ashy hits taste

 

[BongFu]

lots of weed seems smooth if you only take a few tokes of it, how does the smoothness hold up smoking an oz a week, how do the last couple ashy hits taste

This coming from someone who dries their weed in a paper bag. Next please. Hey BTW guys if you are an organic mung nut please post the research papers that support your ridiculous hippy dribble claims.

 

[mexweed]

incorrect, I place the buds in paper bags for roughly 48 hours during low humidity to not over dry them on the hang, it's an intermediate step before jarring

I smoked a little over an oz a week during 'lockdown' went through close to half lb and was still running 6 miles in 45 minutes in sweatpants in 90 degrees, so the smoothness checked out

 

[Douglas.Curtis]

Hey BTW guys if you are an organic mung nut please post the research papers that support your ridiculous hippy dribble claims.

LOL This still never fails to tickle me. After so many people calling my 100% hydro "The most amazing organic they've ever had," it's just funny. I too would like to see these research papers. I LOVE hydro cannabis, but not from the typical grower. lol

Look, the rest of the cultivation world is going to figure it out in time but you have access to the information right now. Cannabis does not care how it gets it's molecules and elements, it is not an organic snob.

Fact is, as I've stated many times over the years, you definitely want to control what's in the root zone with cannabis plants. The more you feed it, the lower the quality goes and (to a point) the heavier the harvest will become. Cannabis will suck that excess up and lock it away forever, all while looking beautiful and healthy.

What are your goals? Plant weight of leaf and stem, or are you looking for only excellent quality flowers? This is what determines where your research should be heading for _your_ plants.

 

[troutman]

Flushing is not a myth and overfeeding is a reality.

Best thing to do is to feed as little as possible.

 

[roybart]

Cannabis actually has a stronger response than grapes to environmental changes. Lots of information out there on the subject to suck up.

Facts are, 50% of the population has up to an average ability to taste. This means only the upper 25% can detect the smaller changes, and the lower 25% have a greatly reduced ability to detect anything.

This is a good question I'd like to see answered. What exactly can be filtered out? What ends up in the oils being extracted?


You got it right the first time. Appreciate it greatly and I'm outta rep for the day or I'd hit you up. Tyvm.

Also taste has direct relationship with smell.My GF has a snout with an olfactory capability of a bloodhound. Thus her sense of taste would not be the same as mine.

 

[Weird]

the art of growing proper smoke is absolutely lost on the "bright" minds that have entered the canna space


painfully how fucked up things get when money is the main motivator

 

[mexcurandero420]

Is this paper peer viewed by others?

 

[SuperBadGrower]

The RX one isn't, and probably won't be. (What they released publicly probably cannot be published unless the journal has rather low standards)
The 'lead researcher' on that hasn't published anything since 2012. Moreover Therevverend actually raises a valid point about conflict of interest.

The guelph paper is a master's dissertation. That means it is done by a Masters student with help of a PhD advisor, with the goal of getting a diploma (MA).
These kind of works can be published in a journal if it is really novel.
Some people who do MA want to go on to be the world's most autistic researcher. Other people want to put in the absolute minimum of work and just escape university with a degree. That's why the world doesn't pay attention to those kinds of works. Someone in a PhD program you can be more sure that they really invest themselves in the subject matter.

So, if your paper is not published in a journal it's (probably) not going to get peer reviewed. I'm pretty sure that was done by someone who just likes weed lol. It could have been anybody from this forum. A guy with an unfinished MA in environmental science is about as far from "BIG MONEY WEED PHARMA" as it gets. If it werent the only paper of its kind, nobody outside of that uni would have read it.

I say all that as someone who flushes nothing except the toilet. Imagine if everybody could chill out and learn to question & criticize their own beliefs and habits

Not everybody agrees that the methods used today lead to the best results: https://en.wikipedia.org/wiki/Against_Method
The author famously describes how galileo would have been labeled as pseudoscience in today's climate. (But Galileo wasnt selling weed nutes)

 

[therevverend]

Moreover Therevverend actually raises a valid point

Oh I got thrown a bone, must be my lucky day.

Hey BTW guys if you are an organic mung nut please post the research papers

Obviously no one, including you bong fu, is going to post research papers on fertilizing cannabis at the end of flowering because the Guelph paper is the only one and not a very good one at that. However there's a vast amount of research that's been done on growing other flowering plants. Tomatoes, hops, potatoes, tobacco, apples, grapes, all kinds of berries, fruits, and vegetables, you can find research on all of it. I don't know anyone, any source, that recommends pumping any consumable plant, let's say, tomatoes, right at harvest time.

The only gardeners pumping their plants with nutrients right up to harvest day would be uninformed uneducated misled greedy cannabis growers who have way more $$ then sense, who wouldn't know an apple from a turnip from a soybean. Next time you see a field of corn, go ask the farmer what he thinks about 'flushing'...

 

[SuperBadGrower]

Well I don't think all those plants are treated the same. Tomato and cucumber are fed the strongest concentrations right before harvest, but strawberries are not. On this website you can compare hydroponic fertilizer recommendations for all kinds of crops:

https://www.haifa-group.com/

crop guide > plant > "Fertilization of (plant)"

 

[p0opstlnksal0t]

Well I don't think all those plants are treated the same. Tomato and cucumber are fed the strongest concentrations right before harvest, but strawberries are not. On this website you can compare hydroponic fertilizer recommendations for all kinds of crops:

https://www.haifa-group.com/

crop guide > plant > "Fertilization of (plant)"

Also to add to your statement, It's hard to compare techniques with a plant that we are after it's fruit vs a plant we are after the sexual reproductive organs (flower).

Most data we have on crops are for the fruits they produce. What other crops out there do we target the flower as the "crop"

 

[Douglas.Curtis]

Next time you see a field of corn, go ask the farmer what he thinks about 'flushing'...

What purpose would that serve, the farmer is not smoking the corn, you are not smoking the corn, nobody is smoking vegetables here.

In addition, corn is not a Hyperaccumulator like cannabis.

When talking jet engine mechanics, referencing parts and operations of a piston engine is generally useless. Yeah, cannabis and corn are both plants but they're worlds apart when talking nutrition.

 

[MindEater]

If reducing feed doesn't lower nute levels in the plant, then why do you have to feed a plant more than once? It's utterly stupid to argue that plants can't have nute levels reduced by reducing feed, an utterly stupid argument to claim farmers don't flush:

"My understanding of the biological impacts of Carbon-to-Nitrogen ratios in soils came from an experience I had years ago. I came across a well respected group growing Hatch peppers in the Southwest who were looking to increase the sustainability of their operation and follow their interpretations of the benefits of increased Organic Matter (carbon) in the soils as explained by their local NRCS advisors. They began incorporating left over corn stalks into the ground with the goal to improve soil structure and overall soil health.

The standard practice was to take tissue samples at several stages of growth to develop fertilizer recommendations. The season progressed normally, until a spike in nitrate N was detected in the tissues, a condition detrimental to the pepper’s shelf life. By incorporating the previous crop’s stalks into the soil, the group had inadvertently increased the C:N ratio and the growers compensated for N deficiencies by adding supplemental N fertilizer.

Since supplemental nitrogen fertilizer was added to keep tissue levels within accepted sufficiency ranges early in the crop life, a nutrient loading condition occurred in the soil. As the season progressed and the C:N ratio began to lower, the plants had more nitrogen available than they required at the tail end of the season, having the unintended consequence of affecting crop’s quality. " - Alberto Diaz, Certified Crop Adviser, https://www.linkedin.com/in/alberto-diaz-cca


5 seconds of Google-fu shows what the 21st century cookie-growing Instagram posting Boveda boys don't wanna see.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324167/

https://www.hindawi.com/journals/jfq/2019/9428092/

https://www.researchgate.net/publication/301674219_Crop_responses_to_nitrogen_overfertilization_A_review

https://www.thefencepost.com/news/high-nitrate-in-hay-killing-beef-cows-in-complex-ways/

 

[indagroove]

Most data we have on crops are for the fruits they produce. What other crops out there do we target the flower as the "crop"

Cotton would be the main flower crop I'm aware of, which interestingly enough is also regularly defoliated as part of the standard grow process.

 

[SuperBadGrower]

If reducing feed doesn't lower nute levels in the plant, then why do you have to feed a plant more than once? It's utterly stupid to argue that plants can't have nute levels reduced by reducing feed,

What is this borderline trolling?. Plants need 'nutrients' to make new growth. An annual plant that is a week from death does not make much new growth. You realize this is a thread about flushing, and the discussion is about whether or not growers of weed should feed their plants in the last week(s)?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324167/

https://www.hindawi.com/journals/jfq/2019/9428092/

https://www.researchgate.net/public...ponses_to_nitrogen_overfertilization_A_review

https://www.thefencepost.com/news/high-nitrate-in-hay-killing-beef-cows-in-complex-ways/

"Overfertilization leads to bad results" x 4

Thank you captain obvious.

Sorry to be rude but this kind of low quality contributions don't further the discussion. You simply googled nitrogen excess and pasted 4 articles about it. nothing you said is related to the subject matter, but you act like an extreme tough guy about it.

 

[blazeoneup]

I'm not growing to please a lab result. I'm growing to please my senses and appeal to them.

I personally don't flush to remove nutrients from the plants persay. I flush to remove available nutrients from the medium forcing the plants to use up all that sugar stored in the leaf tissues to finish off it's reproductive cycle. I think to produce the sweetest flowers one must allow the sugars of the leafs to make way to the flower of the plant. I grew in DWC long enough to flush with plain RO water and monitor the flower growth and trichome ripeness and I can assure you when I switched from nutrient solution to the ro water the plants didn't just stop production, flowers still swelled leafs changed from greens to fall colors and the trichomes finished ripening just fine. I've stuck with the flushing in soil because of the results in hydroponics and it seems to have an impact I can go from healthy green to fall colors with a flush cycle. To each their own peace and puffs blazeoneup!

 

[djonkoman]

If reducing feed doesn't lower nute levels in the plant, then why do you have to feed a plant more than once? It's utterly stupid to argue that plants can't have nute levels reduced by reducing feed, an utterly stupid argument to claim farmers don't flush:

"My understanding of the biological impacts of Carbon-to-Nitrogen ratios in soils came from an experience I had years ago. I came across a well respected group growing Hatch peppers in the Southwest who were looking to increase the sustainability of their operation and follow their interpretations of the benefits of increased Organic Matter (carbon) in the soils as explained by their local NRCS advisors. They began incorporating left over corn stalks into the ground with the goal to improve soil structure and overall soil health.

The standard practice was to take tissue samples at several stages of growth to develop fertilizer recommendations. The season progressed normally, until a spike in nitrate N was detected in the tissues, a condition detrimental to the pepper’s shelf life. By incorporating the previous crop’s stalks into the soil, the group had inadvertently increased the C:N ratio and the growers compensated for N deficiencies by adding supplemental N fertilizer.

Since supplemental nitrogen fertilizer was added to keep tissue levels within accepted sufficiency ranges early in the crop life, a nutrient loading condition occurred in the soil. As the season progressed and the C:N ratio began to lower, the plants had more nitrogen available than they required at the tail end of the season, having the unintended consequence of affecting crop’s quality. " - Alberto Diaz, Certified Crop Adviser, https://www.linkedin.com/in/alberto-diaz-cca


5 seconds of Google-fu shows what the 21st century cookie-growing Instagram posting Boveda boys don't wanna see.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324167/

https://www.hindawi.com/journals/jfq/2019/9428092/

https://www.researchgate.net/public...ponses_to_nitrogen_overfertilization_A_review

https://www.thefencepost.com/news/high-nitrate-in-hay-killing-beef-cows-in-complex-ways/

that quote is pretty far off from the situation around flushing in weed.

for one, as already said above, it's about how much new growth there is. nutrients don't disappear, but they can get locked away in plant tissue as structural part. like how you keep needing new bricks if you are building a house, yet limiting the amount of bricks you deliver to the building site won't take away bricks from the building site. it just means the builders either have to slow down building, or get creative with other building materials to get things done.
and maybe early on in construction they got plenty of bricks, so they used them a bit wastefull, then later on if the brick delivery gets too low they break down an early built wall again to re-use those bricks in a more efficient way. so maybe the amount of bricks per kg of house decreases, but the absolute number of bricks present on the construction site only increases.

there is an effect where if you limit the nutrients, overall nutrient concentration across all the plant material does decrease. but it's not a case pof getting removed from the plant, it's just that growth continuees, so total plant matter increases, absolute amount of minerals stays the same, so the relative amount of minerals decreases. but they don't get removed from the plant.

it also means that that decrease in RELATIVE mineral content is dependent on growth. no new plant mass/growth=no relative decrease.

that quote you posted makes perfect sense, but it's all about what happens in the soil, not the plant. it's also specifically about peppers.
the carbon containing stuff from organic matter is food for microbes, but they need to digest it, for that they need tomake enzymes and they need N for that. so if you add crop residues to your field, especially if you dig them into the soil, all the microbes will start to eat it, yet the C/N ratio is too high in C for those microbes, so they take N up from the soil around them, competing with the plants. like with plants that N does not disappear, but it becomes a part of something the microbes build and so is not in a plant available form anymore.
then later as those microbes die they release that same N into the soil again, and it becomes plant available again. so that is that N-spike the quote is talking about. first there was a spike in the soil, which then led to a spike detected in the plant tissue. which is completely logical.

regarding the 'affecting crop quality' part, whatever 'good' quality is can vary a lot by crop or even specific product from a crop, or the purpose you use the product for. try growing something harvested for proteinrich seeds on low N(and the crop is not a legume), and I'm sure you'll see lower product quality.

I think we still have far too little research/evidence to say much about what determines weed quality past the subjective experience. I think we can all agree on that high quality should be smooth smoking with good smell and taste. but to express that into values like nutrient concentration in the plant matter is much more complex, you can't just say something without evidence.
similar to talking about sugars. sounds nice and logical. and there is a short term store of sugar usually present in plant leaves, sugars that were made with photosynthesis but not used yet.
but to proof a claim like that you need to take samples from plants grown at high and low nutrient levels at the end to first proof that the low nutrient treatment actually causes lower sugar levels, you need to determine where(just lower sugar in the fan leaves you cut off anyway? or in the sugar leaves too?), and finally you also need to proof that bud with higher sugar levels smokes less smooth.
it could just as well be that reducing nutrient levels too much decreases growth, leading actually to more sugars heaping up, since photosynthesis continuees while less sugars get built into new growth, so they stay waiting. although there likely is a kind of maximum, I think thoe sugarts in the leaves usually work as a downregulator on photosynthesis. no purpose in making more sugars if you already have plenty, plants are lazy too.

in this case of peppers, the quote specifically mentions that the higher N level in the fruit decreases shelf life. whatever is the reason exactly that increased N decreases shelf life I'm not sure of, might be something like that C/N ratio being closer to what decomposing microbes need for best decomposition, or might be something more plant physiology related.

anyway, spoilage by microbes of a pepper fruit, which is not dried, is a completely different kind of quality factor then how smooth the smoke from a combusted, dry cannabis flower cluster feels on a human's troath.