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University of Guelph paper- Flushing is a myth!

popta

Member
The cake was real. Turned out the graffiti was a lie. Although it may have contained neurotoxin... lol. We'll never be sure.

KNsin.jpg
 

G.O. Joe

Well-known member
Veteran
A question for Mel Frank, posted May 18, 2018:
So, what’s the biggest mistake that growers make, that could easily be avoided?

Oh, I’ll tell you what one of the worst things is: FLUSHING. Totally useless and wasteful.

Really?!?

Totally, totally ridiculous. I don’t know who came up with this concept, it does nothing…You know what I did, I always stopped fertilizing altogether two to four weeks before harvest. Also, potassium. If I gave them anything it would be potassium. It turns out the plant takes up a lot of potassium at the end. A lot more than phosphorus. It also uses a lot of calcium right at the beginning.
 

mexweed

Well-known member
Veteran
some strains will use more ca, P, and K at the various stages of flowering than others

the biggest mistake growers make that could easily be avoided is believing a statement as an end all be all for growing and not just going for it and learning themselves

fuck a canadian university, grow two plants flush one and not the other, how do they smoke after a month cure, no rocket science involved
 

TychoMonolyth

Boreal Curing
A question for Mel Frank, posted May 18, 2018:
So, what’s the biggest mistake that growers make, that could easily be avoided?

Oh, I’ll tell you what one of the worst things is: FLUSHING. Totally useless and wasteful.

Really?!?

Totally, totally ridiculous. I don’t know who came up with this concept, it does nothing…You know what I did, I always stopped fertilizing altogether two to four weeks before harvest. Also, potassium. If I gave them anything it would be potassium. It turns out the plant takes up a lot of potassium at the end. A lot more than phosphorus. It also uses a lot of calcium right at the beginning.
Boom! You said it.
 

Lost in a SOG

GrassSnakeGenetics
Ive had issues with stopping feeding too early in high light and high co2 environment.. Not only do they eat more but co2 causes N to become around 15% less available.

If you have too much N you can lower temps and raise co2 and light levels and theyll eat it.

But the "flushing" philosophy has caused me many problems in soil at least.. its a half truth grow bro science at best.. There isnt one rule for everything especially in a system where there are probably 30-50+ variables at play like the main one really being genetics but then the biggies like VPD, co2, day temp, night temp, night o2, drainage, nute availability in the soil, the moon cycles, soil pH, leaf boundary layer disruption rate, transpiration, PAR , light spectrum quality, daylight integral, the effect of light spectrum on chloroplasts and stomatal conductance, the soil micro biome health etc etc..

I think there is more credit to using good soil and teas, with some extra supplementation if needed around week 4-6 and then starting to water slightly less in the final weeks which is more similar to what happens in alot of cannabis's range in nature. If healthy they just stop eating on their own regardless, i think some people think it will fix their sick probably over fed locked out plants.

Its a fine line but growing dope to the highest level is. :2cents:
 

aridbud

automeister
ICMag Donor
Veteran
Ive had issues with stopping feeding too early in high light and high co2 environment.. Not only do they eat more but co2 causes N to become around 15% less available.

If you have too much N you can lower temps and raise co2 and light levels and theyll eat it.

But the "flushing" philosophy has caused me many problems in soil at least.. its a half truth grow bro science at best.. There isnt one rule for everything especially in a system where there are probably 30-50+ variables at play like the main one really being genetics but then the biggies like VPD, co2, day temp, night temp, night o2, drainage, nute availability in the soil, the moon cycles, soil pH, leaf boundary layer disruption rate, transpiration, PAR , light spectrum quality, daylight integral, the effect of light spectrum on chloroplasts and stomatal conductance, the soil micro biome health etc etc..

I think there is more credit to using good soil and teas, with some extra supplementation if needed around week 4-6 and then starting to water slightly less in the final weeks which is more similar to what happens in alot of cannabis's range in nature. If healthy they just stop eating on their own regardless, i think some people think it will fix their sick probably over fed locked out plants.

Its a fine line but growing dope to the highest level is. :2cents:

And, too, synthetic or organic fertilizers make a difference in taste/burn. Prefer organic, as in teas and water, good soil w/ organic amendments from the get-go....in 40 some years growing, it hasn't made an impact that we flushed the last 1.5 weeks. Those growing with chemicals....nasty taste. To each their own (way of growing), smoking, etc.
 

mexweed

Well-known member
Veteran
flushing is definitely a balance, I think too many people think of it as literally rinsing out the plant like physically from the inside out or something

it's more about starving the plant so it feeds on any reserves it has built up, which takes time, so people that are like yeah I grow hydro I only flush the last 3 days, nope

it's true that flushing hydro typically has a more immediate visual appearance of the plants being starved, but that is not adequate enough time for the plant to fully metabolize any reserves

overfeeding, ph swing in the rootzone causing lockout, things that allow nutrients to enter the cells of the plant that otherwise wouldn't have such as fulvic acid, all play a role in fucking up the flushing balance
 

mexweed

Well-known member
Veteran
it's starving relative to peak flowering, trichomes are produced as a defense mechanism, mild stress that doesn't actually hurt the plant
 

thugpoet

Active member
Flushing is only a means to an end and by no means a hack. The goal to starve the plant until it induces its senescence, with the leaves changing colors as the plant uses up any nutes it has left. This leads to the translocation of the sugars in the plant.

It does not matter whether you grow full organic or hydro, if you don't reach this point before cutting, your weed will never truly be sweet, you'll always have a slight chlorophyl taste/harshness and the difference will be even more noticeable after curing.

Maybe the naysayers aren't doing it properly, so they cannot notice the difference it makes or are simply talking in bad faith, trying to justify force feeding their plants until the last day for bigger harvests.
 
I looked through that thesis and it seems to be very complex research. The author has done a great job and the theme regarding the irrigation strategies for medical cannabis is very interesting. By the way, I have written a thesis on a similar topic and it took me a lot of time to make the research. However, I have friends that found writing help on a site and decided to use their services in order to have the thesis done. Anyway, that's a very well written thesis paper.



______________________________

What? Are you trying to push your own “research”?



I agree with what others have said.

Go smoke a bowl of unflushed Flowers, it’s gross!
 

therevverend

Well-known member
Veteran
When you use terms like starving and flushing people will question what you are doing. When a cannabis plant reaches the end of flowering it reaches a state called senescence. The plant throws the last of it's energy into producing the next generation of it's kind. It pushes the last of the energy it's stored through it's life out of it's leaves, stems and roots into one final push into it's seed-producing parts.

When you're growing in dirt you shouldn't need to 'flush' because your dirt should already be depleted of nutrients. In nature this would happen because the plant will have spent 8 months depleting the soil it's growing in. It doesn't need more nutrients and has reached the end of it's life. It's nearing peak potency, has produced all the resin, cannabinoids, terpenes, etc. it's going to produce.

Hydroponics is different because the plant is dependent on the grower to supply it's nutrition directly but it's the same idea. The plant is no longer producing more stems, leaves, flowers, caylxes, etc. It doesn't need any more food. You aren't 'flushing' the nutrients out of it, if you haven't over fertilized!

To properly ripen, develop it's own unique smell and flavor profile and properly enter senescence the plant needs to run out of food. If you're feeding it you're artificially encouraging it to continue producing vegetative growth and build more flowering clusters. This might sound good, you're getting more weight, if you want to wait two more weeks to wait for the new growth to develop! It interrupts the plants natural life cycle, the ripe parts will over-ripen and begin to degrade, the plant will begin producing chlorophyll again. You may even trick it into thinking it's got a chance to re-vegetate and produce more plant growth. As a grower, you fucked up your plant!

This is one of the main reason people complain about hydro, why so much hydro is crappy, smells and tastes mediocre. A soil grower can make the same mistake by mixing too rich of a soil mix or over fertilizing during flowering! I usually don't fertilize the last month of flowering, since my soil is quite rich. It's easier to add then to take away. A commercial grower is often fertilizing and harvesting his plants based on $ instead of getting the best quality. The best commercial growers understand their plant's life cycle, it's changing needs throughout it's development and know the best results get the most $. A hobby grower who isn't under pressure to produce profitable results shouldn't need to push their plants. Except as an experiment to learn. The only thing you accomplish when fertilizing the last weeks of flowering is pouring $ down the drain.
 

Mr. J

Well-known member
The author is a nublet and he doesn't know what he's talking about. This is why I can't smoke anything that wasn't grown by me. Newsflash!!! Your weed is garbage and practically unsmokable. It all tastes like shit, doesn't burn right, and in general is altogether unenjoyable.
 

CannaRed

Cannabinerd
I have been following the cocoforcannabis schedule/recipe using GH nutrients.
It uses GH nutes but less mL per gallon than using GH schedule.

I will say that my plants start to fade or show senescence long before start of flush.

So maybe I'm not overfeeding, but I'm definitely still feeding the plants. Plants will senesce while being fed.
 

mexweed

Well-known member
Veteran
preventative measures are better than trying to save it at the end

so I like to do periodic plain water feedings, once in starter pots I do plain water 2x aerated worm castings 2x then transplant and repeat, first 2 weeks 12/12 are plain water too
 

BongFu

Member
A recent blind taste test study conducted by RX Technologies, where flushed and unflushed cannabis was handed out amongst “cannabis industry experts” found the study’s participants preferred the taste of unflushed cannabis.

A summary of this study:
• Rx Green Technologies evaluated the effects of different flushing times on chemical profile, flavour, and smoking characteristics in Cannabis flower.
• Flushing periods of 14, 10, 7 and 0 days were imposed on Cherry Diesel.
• No differences were detected between flush treatments for yield, potency, or terpenes.
• Analysis of mineral content of leaves indicated small changes in content of iron and zinc.
• To determine smoking flavour and characteristics, samples of each flushing period were distributed to Cannabis industry experts in a blind taste test. Each participant received one sample of each flushing time without knowledge of its treatment.
• Participants were asked about their personal Cannabis flavor preferences before tasting. After tasting, participants were asked to rate the sample for flavor, harshness of smoke, and colour of ash.
• Cured flower from Cherry Diesel was evaluated by a group of industry experts for flavor and smoking characteristics in a blind taste test. Overall, the duration of the flushing period had no impact on flavor, smoothness of smoke, or colour of ash. The seven-day flush period had the highest “bad” rating (21.1%) and the 0-day flush had the highest “great” rating (16.7%). Most panelists rated the flavor of the samples as “okay” or “good”. The ten-day flush had the highest “okay” ratings at 48.6% and the 0-day flush had the highest “good” rating at 47.2%
• Thus, taste test panellists tended to prefer flower flushed for 0 days
 
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