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Let's define "flushing" once-and-for-all.

Crazy Composer

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First and foremost... this discussion will be kept on topic. Expect opinions to vary.

Flushing means many different things to different people. The word "flush" is used all the time and often the technique being called "flushing" is not really flushing at all.

I hope we can standardize a few definitions here.

The original word "flushing", was used to define a technique where excess amounts of clean water were run through a medium in hopes that it would pick up and remove dissolved salts and minerals from the medium. The reason was to deny the roots access to these salts and minerals before harvest time. Why remove these excess salts/minerals? Well, since salts and minerals are generally fire retardant... it stands to reason that you don't want to dry your herb with any more fire retardant stored in the buds than is absolutely necessary.

THC, CBD, CBN, etc are most potent when burning at a high temperature, like when you're smoking a joint with a red hot cherry. Less clean herb, herb with excess salt/mineral/carbon/chlorophyll content, will burn unevenly, harshly, etc.

What we really should do here is to identify and name the different methods to achieve low salt content in our herb.

IMO... The word Flushing should be reserved ONLY for the above-mentioned method, where excess amounts of water are run through the medium to wash away dissolved salts/minerals.

The problem has been with the use of the word Flushing. When, for instance, I use an organic soil with very little organic matter present, in hopes that by harvest time most of the organic material is depleted, therefore minimalizing the amount of salts being released to the plants... This isn't really flushing at all. It's more of a nutrient step down. There is no formal word to describe this process, so the word "Flushing" is used.

I can see why some people have a problem with the word, because their method requires no flushing... at least not flushing in the classic sense, where tons of water is used to flush the medium prior to harvest. This misunderstanding has lead to some nasty, unwarranted ugliness in this community.

So... what I'd like is for the people with experience in cultivating marijuana to share their ideas as to what we should call the different methods to reduce salts in the herb prior to harvest. Share your observations and experiences, and help us standardize a few definitions we can use to better describe these methods.
 

etinarcadiaego

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Well I wouldn't call it "my idea" but anyone who read the latest grow guide (High Times 2009 Grow Guide) from high times may have read the article in it about how to properly deplete your organic soil of nutrients prior to harvest to get a clean burning finished product.

It said to water heavily the last 36-24 hours to clear out the soil AND don't let it dry out at all, keep it over watered as even depleted organic soil will begin to release nutrients as it dries out and microbial activity resumes.

What do you think of that? "Flushing" or what have you for only the last day or so. I don't believe everything I read, but it made sense when i read it.
 

Tony Aroma

Let's Go - Two Smokes!
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I'm not sure why this in the Organics forum. "Flushing" to remove salts and minerals doesn't really apply when using organic fertilizers, does it? Where are these salts coming from if you do not use chemical fertilizers? And while I can understand removing salts, which are not beneficial to plants (and even harmful in high concentrations), why remove minerals that plants need to grow? Especially at the end when you want your plants to have everything they need to fatten those buds up as much as possible.

FWIW, I grow strictly organic and do not flush, at least not according the definition given above. I do however always water with plain water the last couple of weeks. I don't do this to remove anything from the soil, but just to let the plants use up what's already there. Since organic fertilizers take some time to become available to the plant, I see no point in adding more right before harvest as they will not really be used that quickly. But I definitely want them to have everything they need right up till the very end.
 

lizard_9

Active member
I also think that 24/36h are way too short to allow a full salt release.
My method,that i call "Cleaning" instead of "Flushing",is to water excessively during 10-15 days especially the 5 last days.

@Tony: your plants naturally stop feeding at the10-15 lasts days,we call it "senescence" in french. The leaves change their color for they stop absorbing waht's in the ground and use what they stocked inside themselves.
 

etinarcadiaego

Even in Arcadia I exist
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Does anyone have the High Times 2009 Grow Guide at their fingertips? Refer to the article about flushing.

Mid-way through it highlights Organics, stating flushing with Organics is pointless as the soil will dry out in less than 3 days enough to resume microbial activity again providing nutrients to your plant. I believe it stated you cant "flush" soil, only "flush" the plant. Meaning if we can be certain the plant ONLY get water the last 24-36 hours then the plant has been flushed of nutrients, not the soil. Once the soil dries out it will again be fertile (even if it only contains very low organic matter - it still contains organic matter).

What I took from the article is that you can't flush organics. what would be the point?

I'm not the author, but read the article - to say the least i found it intriguing
 

VerdantGreen

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i agree that this is something that needs sorting out - there is enough disagreement on this whole issue without extra confusion caused by using the same terminology for two different things

perhaps we should call withholding nutrition towards the end 'starving' ?

thats the best i can come up with atm but i will work on it.

V.
 

subrob

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"cleanse" would be a good word for what i do...about 10-14 days before harvest i start w only clean water...some strains i continue giving sugars til a few days before chop...ive always just looked at it as locking out any more nutrient uptake, plants yellow up nicely, and i get a wonderful taste and aroma...
 
C

Classyathome

Yup - exactly as CC posted...

Flushing - pure and simple...

IMHO
 

Tony Aroma

Let's Go - Two Smokes!
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@Tony: your plants naturally stop feeding at the10-15 lasts days,we call it "senescence" in french. The leaves change their color for they stop absorbing waht's in the ground and use what they stocked inside themselves.

As long as they are growing, they must be getting their nutrition from somewhere. If there's nothing left in the soil, then they are forced to take what has been stored in the leaves, hence the yellowing. But one way or another, if the buds are still packing on weight, they must be feeding.

One thing I'm not sure of is how do the plants know to stop feeding during the last 10-15 days. I don't mean to be a smart ass, but they don't know their lives are about to suddenly end. If left on their own, they would continue for some time, maybe several weeks, before finally dying. The only time they stop feeding is when they've stopped growing. Which just so happens to be about the time that most people harvest.
 

Crazy Composer

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Tony Aroma, organic material is broken down by bacteria, etc and reduced back into the base elements. So yes, organic fertilizers contribute salts to the equation. You say you give plain water for the last few weeks... This is what some call flushing, but it really isn't flushing. What would you call that process?

To clarify... plants use sugars for energy, not nutrients. Plants use nutrients, water and light to produce what they're really after... sugar. Plants store their sugars in the form of starches in the root systems at night time, similar to what a potato does. These starches are used by the plant for energy during times of nutrient deficiency in order to have the energy to keep vital systems going. So... when you deny the plant nutrients, it will still be able to continue ripening for as long as the sugar/starch reserves hold up.

The method you employ, letting the plant consume what's there, and not providing any further nutrient, is a method that accomplishes the same end result as the guy who flushes. To harvest herb with as little fire retardant on board as possible.

I will remind folks again... Mother Nature flushes/leaches/douches her soils as well. The rains move dissolved salts/minerals down, away from the reach of plant roots, and some of these minerals become stalactites, crystals, etc. in subterranean caves. Soils that are never flushed naturally become toxic. Organics DO benefit from flushing, or something like flushing. I would put forth to you that without the "flushing" action of rains, the soil on Earth would be dead.
 

VerdantGreen

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Does anyone have the High Times 2009 Grow Guide at their fingertips? Refer to the article about flushing.

Mid-way through it highlights Organics, stating flushing with Organics is pointless as the soil will dry out in less than 3 days enough to resume microbial activity again providing nutrients to your plant. I believe it stated you cant "flush" soil, only "flush" the plant. Meaning if we can be certain the plant ONLY get water the last 24-36 hours then the plant has been flushed of nutrients, not the soil. Once the soil dries out it will again be fertile (even if it only contains very low organic matter - it still contains organic matter).

What I took from the article is that you can't flush organics. what would be the point?

I'm not the author, but read the article - to say the least i found it intriguing

etina - that sounds interesting - id like to hear more. i thought that roots could absorb nutrients better when the soil was wet rather than dry.
also i actually water less as harvest comes near as it helsp the plant finish (imo) and also reduced the chance of mold.

V.

p.s. i would also agree that senescence plays a big part in what happens in the last couple of weeks, but starving the plant helps the plant to use the nutrients stored in its leaves making the smoke better.
 

lizard_9

Active member
You are right Tony,as long as the buds are packing on weight,the plants need to be fed.

I also agree that as long as they are feeding they must take it somewhere,and of course they don't know they're going to die.
But never stop the feeding and you'll see that about 10-11 weeks flowering an Indica will turn totally yellow-red and start dying by itself.
It also depends on what kind of stone you are awaiting from your weed. Light or very narcotic.
 

Dr.NO

Active member
Even when using organic nutrients wouldn't a flush lasting a week or two be beneficial for at least leaching excess salts and other materials if it infact does not leach out the majority?
 

VerdantGreen

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......
I will remind folks again... Mother Nature flushes/leaches/douches her soils as well. The rains move dissolved salts/minerals down, away from the reach of plant roots, and some of these minerals become stalactites, crystals, etc. in subterranean caves. Soils that are never flushed naturally become toxic. Organics DO benefit from flushing, or something like flushing. I would put forth to you that without the "flushing" action of rains, the soil on Earth would be dead.

whilst rain will leach some minerals from the soil, most of it is held or fixed by the microbes and funghi and this cannnot be flushed - this is why many say that flushing/leaching organic soils is pointless.
incidentally stalagtites are usually formed by rain dissolving limestone rock rather than minerals from the soil.

V.
 

etinarcadiaego

Even in Arcadia I exist
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etina - that sounds interesting - id like to hear more. i thought that roots could absorb nutrients better when the soil was wet rather than dry.
also i actually water less as harvest comes near as it helsp the plant finish (imo) and also reduced the chance of mold.

V.

p.s. i would also agree that senescence plays a big part in what happens in the last couple of weeks, but starving the plant helps the plant to use the nutrients stored in its leaves making the smoke better.

Verdant, I do (or did) the same thing and watered VERY little my last 7 - 10 days. I also heard the same the thing about plants and feeding when the soil was wet. I think the article said you have to over water them during this time so the roots got nothing but water. Meaning water until you get TONS of runoff, then water some more, and keep it like this the last day or so. It didn't go into great detail and i don't have it in front of me.

In Organics you guys have taught me to feed the soil not the plant, so this entire thing is interesting as it implies you flush the plant not the soil. I don't know. I read it and can remember it, but I've no opinion one way or the other.

I'll give it a try my next time in flowering (soon!!) but have no experience with this technique, thus i have no opinion :)
 

VerdantGreen

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come on microbeman - lets have it ;)

be gentle with us :D

microbeman! microbeman! microbeman!
 

Dr.NO

Active member
Tony the plants do know it's time to die because they evolved over millions of years to know when their time is up even if winter conditions do not begin to take their toll. There are exceptions like reveging but for flowering buds will eventually begin dying on their own.
 

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