Final Flush: Myth Or Fact?

[HigherTheHigh]

I can flush a plant and smoke it as soon as its ready for curing with no harsh taste, no black ash, burns pretty great, nothing bad, the curing just gives me an all around better tasting.

If i dont flush theres not a chance im getting a nice taste, black ash, hard as hell to keep it burning.

Iv ran near the 1000 of plants in the past 3 year and trust me you need to see for yourself, reading others opinions doesnt always count.

Only you can decide whats best for you with your own tests.

All i have ever done is go via some of my own schedules as well as the great @Cultivator and ever since iv flushed i get no harsh taste what so ever.

All i ever see is big companies telling you to flush, if there saying to do it and there not benefiting $$$ from it, then there must be some truth, i know a fair amount of growers out that that do mass size grows for pure cash, they always flush and if they dont, well, there names tarnished by dealers.

Like i said, do your own tests, im in organic now so i wont really flush but when i go back to synthetic nutes you bet your bollox i will flush .

 

[TheFertilizer]

What about the fact that the buds don't take up any nutrients from the soil at all? Are you saying a plant starved of immobile nutrients might build buds that taste better than one that is fed?

Yeah basically. I'm saying that could be an explanation for why it would be any different at all. How exactly that would manifest from those conditions I wouldn't care to speculate, but really my point is just that as long as people still firmly believe that the flush makes a difference, they'll come up with new theories to explain it.

 

[Drivejunky95]

To Flush or Not to Flush in Cannabis Cultivation

What exactly is being gained — and lost — in this commonly accepted practice?

www.cannabisbusinesstimes.com

Pt 1

The motivation for understanding flushing actually has to do more with money, not cultivation. A five- to 10-day flush represents as much as 12.5 percent of the plant’s flower time. Plants do not add mass in the absence of nutrients, so the loss of yield at the height of the plant’s ability to produce it makes this flavor-enhancement technique an expensive one.

Pt 2

Under normal growing conditions, when nutrient availability exceeds demand, plants will store nutrients. When availability is low, they will cannibalize older plant material, robbing NPK and magnesium, and moving them to needy growing points.

Think about that. Flushing causes nutrients, especially nitrogen, to be moved into the buds to support growth. So although growers aim to remove nitrogen from the buds by flushing, the plant concentrates nutrients in the buds from other places in the plant. These nutrient concentrations are less than if the plant were nourished during the flush week, but concentrating less in the plant biomass is entirely different than removing nutrients from the biomass.

Pt 3

We believe most growers recognize they are trading yield in favor of the quality enhancements. But it is not clear they have an appreciation for what exactly that quality is costing them or what exactly is being gained.

To us, the concept that flushing somehow changes the chemistry in plant tissue that has been laid down for weeks requires a scientific explanation because that concept seems akin to claiming that the car engine is cleaner after washing the car’s hood. Nutrients are locked in the plant, and an external flush cannot undo the complex biology that locked them in.

 

[Aroxol]

Alright friends, I have a mission for all of you should you wish to accept it. IMO the initial topic of this thread is played out and we’re ready to move on (forgive me in advance). So where do we go? Using our collective minds to explore new ground that could in some ways could potentially evolve/ change cannabis growing.

Here’s my challenge: I want to know absolutely EVERYTHING any/ all of you know about shungite and fullerenes - the interaction with water, macronutrients, micronutrients, pH, and how that benefits or works against cannabis growth stages. I can’t help but feel like “structured water” and elite shungite could play an interesting role in cannabis growth.

Could be way wrong, but I’m not finding a lot of data on it specific to cannabis and a lot of the scientific studies on fullerene interactions with water go beyond my brainpower.

While we can still fight debate flushing or not flushing, I’d personally get a lot more enjoyment out of hijacking this thread (where I know there’s a lot of brain trust) to discuss new (or fairly new tech) related to growing.

 

[jodyhighrollr]

I have tasted bud that people said was unflushed and have tasted a nasty harsh flavor and it was hard to burn but now with some experience I think it didn't dry or cure properly. I only ever flushed well using synthetic nutes and my bud always tasted great but I will say things taste better and look nicer now. I now grow in organic supersoil and give tea right up until harvest. People say the plant can't tell the difference between synthetic and organic nutrients but I think there is a reason why people will go out of their way and pay more to buy organically grown flowers that are cured properly because in my opinion the flavor and smell is better.

 

[LiberalThinker]

I think 'organic vs synthetic' is a completely different discussion to the OP about flushing.

 

[jodyhighrollr]

I think 'organic vs synthetic' is a completely different discussion to the OP about flushing.

If you go through and read the post it has been mentioned before. They are saying the reason you wouldn't flush because after the plant converts the nutrients to make it available it can no longer tell the difference between whether the nutrient was organic or synthetic so it is very relevant to this post. And my point is why would people buy organic over non organic bud if they couldn't tell the difference in quality. Why would there be a difference in quality if the plant can't tell the difference between the source of nutrients?????

Hate to be cliche, but gotta interject something. Haven't even finished my first grow yet LOL..

Not to sound rude but a lot of these guys have been flushing for a long long time and have finished multiples grows to make changes and form their own opinions.

 

[LiberalThinker]

If you go through and read the post it has been mentioned before. They are saying the reason you wouldn't flush because after the plant converts the nutrients to make it available it can no longer tell the difference between whether the nutrient was organic or synthetic so it is very relevant to this post. And my point is why would people buy organic over non organic bud if they couldn't tell the difference in quality. Why would there be a difference in quality if the plant can't tell the difference between the source of nutrients?????

OK. Going 'organic' is a philosophical decision rather than one rooted in fact. As you say, plants can't tell the difference. The main advantage with organic is that it's harder to go wrong i.e overfeed, because the nutrients are released more slowly.

 

[Ganjagrandaddy]

Thanks Blew!

@Drivejunky95, I have a link in my signature to a scientific analysis on preharvest flushing.
Here it is:

A critical look at preharvest flushing

Pre harvest flushing is a controversial topic. Flushing is supposed to improve taste of the final bud by either giving only pure water, clearing solutions or extensive flushing for the last 7-14 days of flowering. While many growers claim a positive effect, others deny any positive influence or...

www.420magazine.com

Flowers do not uptake nutrients from the soil, whether synthetic or organic. The plant takes up the nutrients and converts them into sugars to build the buds.

It's the dry and the cure that preserves the flower smell and taste and rids the buds of harshness.

Huge arguments have gone on over this, but more and more growers are coming to the conclusion that flushing is bro-science.

Keep in mind that you should do whatever you feel good about, but I feel there is no reason to starve a plant just when you want it to power its way to the finish line.

Note: this does not apply to flushing to correct soil imbalances! Just the alleged "cleaning the nutes from the buds before chop" flushing .

woot woot. well defended for us no flushers. people shun me in the street for being a no flusher. I had a group with pitchforks on my garden with a burning garden rake wearing geopots with eyeholes in.!!!!

I dry trim after a very very slow dry. The science supports the method of slowly allowing her to die off while drying out totally. I dont have any harsh product in my last 8 ladies but they still need a week curing to get the real flavours and taste activated , more cure 8s a luxury this way not a neccesity to "rescue" alfalfa/hay hybrids!

 

[Crysmatic]

But then why would you do it if buds are composed mostly of nitrogen?

Plants are mostly Carbon, Hydrogen, and Oxygen! About 4% total weight comes from your nutrients.

@InTheShed
Plants absolutely take up minerals. That's what makes leaf samples useful!

The immobile minerals a developing leaf takes up is what it has all its life. The mobile nutrients - N, P, K, Mg - are used up from the larger leaves first, buds last. It's important not to overfeed at any point.

Greengenes said giving straight water the last two weeks causes plants to use up the stored sugars - sugars makes smoke harsh.

I'm not sure what happens inside a plant during cure. I know you're supposed to keep vpd up so the plants still carries on bilogical processes for a time. Eg 60F/60% rH. I'd look into tobacco curing (as a mature industry).

 

[LiberalThinker]

Plants are mostly Carbon, Hydrogen, and Oxygen! About 4% total weight comes from your nutrients.

@InTheShed
Plants absolutely take up minerals. That's what makes leaf samples useful!

The immobile minerals a developing leaf takes up is what it has all its life. The mobile nutrients - N, P, K, Mg - are used up from the larger leaves first, buds last. It's important not to overfeed at any point.

Greengenes said giving straight water the last two weeks causes plants to use up the stored sugars - sugars makes smoke harsh.

I'm not sure what happens inside a plant during cure. I know you're supposed to keep vpd up so the plants still carries on bilogical processes for a time. Eg 60F/60% rH. I'd look into tobacco curing (as a mature industry).

The bacteria during curing use up the sugars, and whatever nutrients are left.

 

[Conradino23]

Plants are mostly Carbon, Hydrogen, and Oxygen! About 4% total weight comes from your nutrients.

Yes obviously, water adds to 75-80% of the above ground mass. I misphrased unfortunately, what I meant was that nitrogen is the most accumulated nutrient in plant tissue although it’s only 1-2% on average, a building block for amino acids.

 

[dakotamoon]

With a coco grow - I'd like to reuse my coco for another few grows, if I flush with just water, am I not totally destroying the ppm of the coco, so that it has to be recharged again?

 

[Ganjagrandaddy]

You know where you ought to repost that intact? Here:

A critical look at preharvest flushing

Pre harvest flushing is a controversial topic. Flushing is supposed to improve taste of the final bud by either giving only pure water, clearing solutions or extensive flushing for the last 7-14 days of flowering. While many growers claim a positive effect, others deny any positive influence or...

www.420magazine.com

They could use another dose of science in that thread. It's getting overrun with magic!

 

[sadhu9]

So...ignore the actual science that says you're flushing nothing from your buds?

Total stoner science. But beware, you're going to get some in here that say science doesn't matter and their own "experiments" show otherwise lol

Irrigation Management Strategies for Medical Cannabis in Controlled Environments

The effects of flushing were also investigated to determine whether it had the intended effect of reducing nutrient concentrations within the dried bud. Through the use of psychrometers, water status (cWP) thresholds were correlated with humidity (cVPD) thresholds and reduced irrigation frequency resulting in water use reductions up to 45.7% which had negligible impacts on yield and cannabinoid profile. Flushing was found to be ineffective in removing any significant amount of nutrient from the bud.

Section 6.2

The practice of flushing is a current common industry practice but there is no evidence in published literature of its effectiveness in reducing nutrient concentrations within the bud or even whether or not this is a desirable result. After testing the nutrient concentrations from each treatment from three separate experiments, there were no significant differences in nutrient levels between any treatments within each experiment. This result showed that the intended purpose of flushing to reduce nutrient concentrations within the bud has no effect. These data show that for the last two weeks of the flower cycle for cannabis, it was possible to use no fertilizer water for irrigation with no significant impact on yield while saving input costs on fertilizer.

Did this study use soil only in their assessment ? I run a RDWC system and have always been told to flush for 3-4 days. I use RO water with a root scaler (UC roots from Current Culture) for the flush. What's your take? Thanks

 

[Drivejunky95]

Greengenes said giving straight water the last two weeks causes plants to use up the stored sugars - sugars makes smoke harsh.

Flushers add molasses to water during the final stages though, dont they?

 

[Drivejunky95]

With a coco grow - I'd like to reuse my coco for another few grows, if I flush with just water, am I not totally destroying the ppm of the coco, so that it has to be recharged again?

Coco really reusable. Flush, take ppm readings of runoff and pre charge again if needed. Tap water better than RO to keep the Calcium in the coco cause coco CEC eats it up like crazy.

 

[SteveJasmine]

True, but in contrast, flushing, which stresses the plant and leaves only mobile nutrients available slowing development processes, I'd think you'd want some fertilizer.

The medium probably has enough to supplement during the final weeks. But flushing everything out... nah.

Says it didnt negatively impact yields, doesnt say continuing to feed will positively effect them

Stressing your plants in the final stages can increase resin production. Starving your plants can be a good thing.

Is this correct?

 

[SteveJasmine]

With a coco grow - I'd like to reuse my coco for another few grows, if I flush with just water, am I not totally destroying the ppm of the coco, so that it has to be recharged again?

With reusing your medium, aren't you concerned with pests and contamination?

 

[Drivejunky95]

Stressing your plants in the final stages can increase resin production. Starving your plants can be a good thing.

Is this correct?

No idea, dude. Seems you can not flush and properly cure buds just fine, and you get 1-2 weeks more worth of healthy growth. Just my take from all this.