Is flushing really the thing to do

[Billymgb]

So I have been on the fence about flushing, And this morning I was watching a video on youtube from "MR GROW IT" and he read a report done by a commercial grower where they grew a couple strains and they did a 14 day flush 7day flush and a 0 day and the lab tested everything and pretty much came to the conclusion that flushing does not make the weed better. Check out mr grow it and listen to him read the report. Pretty cool.

 

[TripsRabbit]

The flush let's the plant use nitrogen and other nutes stored in the leaves as fertilizer the last few weeks and makes it smoke smoother. Try your own test and find out for yourself, it really makes a difference on how bad it chokes you and tastes.

 

[mysticepipedon]

What was the lab testing for? Is there something they can test that correlates to harshness?

 

[lvstealth]

i saw that. the methodology is not stated very well. but there are other ones, older, with the same results and better "science" in some areas.



it sort of looks like if you call it flushing, it is not beneficial, but if you call it stopping nutes and just watering, it seems to be $ saving if nothing else.

as for taste and ash and all, the study didnt have any methods and controls listed so how can you tell if it is any good science wise

edit: heres the study mr growit posted

Cannabis Flushing Research Study

In our research study, RX Green Technologies evaluated the effects of different flushing times on chemical profile, flavor, and smoke of cannabis flower.

www.rxgreentechnologies.com

 

[lvstealth]

What was the lab testing for? Is there something they can test that correlates to harshness?

it wasnt a lab per se, it is a company who sells stuff to cannabis growers.

they said they got people to smoke it... they stated no controls, nor who tested it. they didnt state any specifics, so it could be a gaggle toking up, or experts. but we dont know.

this is all they said about it:

"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 color of ash (Figure 5a-d) (P < 0.05). 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% (Figure 4a).

The terpene profile, as tested by a third-party laboratory, indicated earthy to spicy flavors for all flush treatments. Most panelists rated the samples as either “earthy” or “sweet” (Figure 5b). Sweet was chosen as the predominant flavor by 38.9% of panelists for the ten and seven-day treatments and 32% of panelists selected sweet as the dominant flavor for the zero-day treatment. Panelists selected earthy most frequently (32.4%) as the dominant flavor for the 14-day flush.

Taste test panelists rated the ash color and smoke quality of each sample. Ash color was predominantly black or gray (Figure 5c). Smoothness of the smoke increased with decreasing flushing time, although was not significantly different (Figure 4d). Thirty-six percent of testers rated the smoke from the zero-day flush flower as smooth whereas only 19.4% rated the 14-day flush flower as smooth. The 14-day flush had the highest percentage of harsh ratings (41.7%) compared to other samples. Panelists were asked for their flavor preferences before testing in order to determine whether personal preference would affect taste test results. Statistical analysis determined that personal preferences did not influence taste test outcomes (data not shown)."

 

[mysticepipedon]

That's interesting. Growing in organic soil, flushing is not something I consciously do. I don't add nutrients at the end of the grow, but most of them are in the soil, anyway.

 

[Billymgb]

Thanks for all the replies, I wonder how many of us, just on this forum flush.

 

[Backyard_Boogie]

Yes I agree the flushing process is more important with certain mediums. When using soil especially organic soil the need to flush is much less.

 

[Oldmanbud50]

Thanks for all the replies, I wonder how many of us, just on this forum flush.

I did my last 1. But will try with this 1 n let u know results.. Good thread

 

[lvstealth]

the way i understand it is that it does no good (the report says) to feed nutes the last 2 wks, so if you are not feeding nutes, you are just watering... flushing is just watering... sounds a lot like the same thing.

they dont actually define flushing in the study. they could be putting water through it at any rate and we have no idea.

this is a study from 2017, i think. many of the charts seem to be the same from one study to the other, as though they took his findings.



this study seems more "sciency" he describes how he flushed, when and how often and a lots more control oriented study.

"...the following treatments were monitored for plant water potential during the treatments and subsequent bud nutrient content was determined on 3 separate experiments with each treatment:
1) Control Treatment with 10L initial flush completed twice and non-fertigated water until harvest
2) Control Treatment without 10L initial flush and non-fertigated water until harvest
3) Mild-Stress Treatment with non-fertigated water until harvest
4) Mild-Stress Treatment with fertigated water until harvest
5) Moderate-Stress Treatment with non-fertigated water until harvest
6) Moderate-Stress Treatment with fertigated water until harvest T

The first irrigation treatment was the ‘control’ which was the standard irrigation procedure used in the facility. This treatment has irrigation events every 2 to 3 days. The second irrigation treatment termed ‘mild-stress’ was an irrigation event applied every 2 days, and the third irrigation treatment termed ‘moderate-stress’ was an irrigation event applied every 3 days."

anyway, the study by Stemeroff seems a much better example of science. the one mr growit went over seems just a company wanting to sell you its nutes and stuff.

 

[Pippins]

None of the good growers I know irl "flush." I'm amazed anyone still does, just goes to show you we have a long way to go in debunking bro science and "old wives tales" in cannabis growing. The final weeks of flowering are when the buds pack on weight and delicious flavor, it makes no sense to stop feeding them or especially to drown them in water during this critical time.

 

[lvstealth]

the study (and many other studies) says there were no discernable or chemical differences in the plants who got nutes and didnt in the final 2 weeks. so, no need to give feedings in those final 2 weeks according to the science.

 

[lvstealth]

this is a long (and i mean LONG!!!) video about some myths and such regarding cannabis. the lady will answer her email too! lol.

mythbusting

yay! i linked!!! weee!!!

 

[30roll]

Can we get a synopsis???

 

[lvstealth]

heres what its touted as,

"Washington State University Horticulture professor Linda Chalker-Scott ... talks about the benefits of arborist chips and detrimental effects of cardboard and other sheet mulches, soil conditions, specifically the importance of soil tests, perched water tables in containers and landscapes, nutrient toxicities, the fallacy of humus as a naturally occuring substance, critical evaluation of all kinds of products and practices, and myth busting - when .edu research goes head to head with .com claims"

some of what she says is too much for my level of comprehension, not at all her fault. but she seems to be a scientist who now works at WA state and since it is legal there, she has taken on a unique roll in myth busting for cannabis growers

the first part is about the "seeds from china" - the issues and the scam.

oh... and they talk a lot about "teas", none of it any good

talks about bio char in a positive way

 

[Dub_City405]

Depends what youre growing with. Stuff is to simple.

 

[ReeferRon]

IDK man I didn't flush this harvest. But I did for many years. I guess I'm still man enough to say, "I don't know."

This I have noticed... over the years I've met growers who run several different strains and they all taste and smell similar. And I've been to dispensaries here in Detroit where its the same deal. 20 strains, all smell and taste alike...?lol

I always chalked it up to being because they use the same nutes on every strain and get some...residual smell and flavor from them?

But that doesn't hold true because I use the same brand nutrients on every strain and they are always very different in smell and flavor. Even same strain, different phenos are very different. So.. I don't know.

Youtube weed scientist say no need to flush, so everybody stops. Guess ill stop too. I would hate to be the last kid on the playground who still believes in Santa.

 

[Dirtbag]

The debate over this will rage on for years. All of the highly respected professional growers I know use just water at the end for anywhere from 5 to 10 days. I don't know anyone who feeds right to the end except a couple folks on this site. I personally use just water for the last week or so.
I have tried tapering feeds and feeding right to the end 3 seperate times to experiment myself, and all 3 times my crop didn't burn the way I'm used to. Black ash, joint wont stay lit etc.. BUT im no expert and that should be taken as entirely anecdotal observation, it's not evidence of anything.

One of the most interesting things I took from the folks who did that study was something they said about why they did the tests. It's because cannabis growers for decades have done things by tradition using methods and techniques handed down by word of mouth that they used because they worked. They didn't know WHY they worked, as the science hadn't caught up yet.

Kinda like way back when they used to drink beer instead of water because water made them sick. Didn't realize the boiling is the part that mattered, just knew that if they made beer they'd be ok to drink it.

 

[Enforcer]

Growing in coco DTW I have fed until chop, flushed with a large amount of water right before harvest, leeched the last 1-2 weeks with Advanced Nutrients Flawless Finish, Botanicare Clearx, 200ppm Epsom salts solution (don’t ever do that), and plain RO water. As a home grower I’m not really concerned with max yield but rather the experience.

By far, and I mean by FAR, the best results I’ve had have been with plain RO water. Smooth, less harsh smoke with excellent natural flavors and awesome smell. So as far as I’m concerned the debate can rage on, but I’m always running plain RO the last 2 weeks. It brings the dank!

 

[lvstealth]

hahaha, i am searching scholarly articles, seeing what facts are really out there... i just found this

Cannabis sativa, meaning “cultivated Cannabis,” was so named by Fuchs in 1542

fuchs... the guy that named it ... and yeah, pronounced just like what im thinking... tell me im not the only one who giggles at this?

also, i did not know it is "...established that although Cannabis seems to have originated in the Tibetan Plateau at least 19.6 million years ago, it has also been indigenous to Europe for at least a million years" - i heard the rumor humans brought it to EU, guess not, we arent that old. finally, something that is not humans fault!