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

[Grat3fulh3ad]

Just my 2cents, CC...
first off... awesome thread... consensus on usage of terms is mucho importante`.

secondly... In all my time growing, I have only ever used "flushing my medium" ,as you described it and defined it in your first post, a hand full of times... Usually it was in response to having overfed, and I can't remember the last time I did it, it has been so long.

When I use the term flush am usually using it in terms of flushing the plant... I probably contribute to the misunderstanding by doing so, if people read it as something one does to the medium... In my usage "flushing the plant" simply means allowing the plant to use up it's store of nutrients late in flower...

I don't know what the correct term would be for reducing or eliminating unnecessary nutrient late in flower to allow the plant to metabolize it's stores, that's why I call it "flushing the plant", but I'm open to terminology suggestions...

 

[jaykush]

dont forget to take into account what is "available" and what is not. some minerals and nutrients just don't move around in the soil much some do. this link on phosphorus gives weight to both sides of the discussion. depending on which form the nutrient is in, as well as the soil its in and even how its is applied.

http://www.extension.umn.edu/distribution/cropsystems/DC6795.html

What I hear from some people in here is that organic soil needs no flushing because ALL of the ionic salts are locked up in microbes.

yea simply not true and not physically possible. but it does play a major role in some soils.

 

[Hank Hemp]

I agree with Crazy. I do not "flush"(hate quote marks), I cut then stops nutes. With organics this is all I feel is needed. Good topic Crazy.

 

[DARC MIND]

CC im not saying your wrong and I understand your point of view. The above was my opinion on the role excessive rain water plays.
I also do understand were talking about pot =) and Im with Jay on this

my opinion is it totally depends on what you grow in and how, simple as that.

Not all nutrient is locked in the microherd, of course, otherwise run-off from soil would yield ZERO nutrient content

again im with jay and MM
on what media or soil you grow in and how you grow.
some feed with ACT/compost and or soil amendments (rock dust,clay,kelp etc) were others top dress with organic matter/manure(guanos,meals etc) and some water more then others, while some may not drench or water till run off. Plus the diversity of soil mixes or just as diverse as the soilless mixes and container sizes(root size). some may have a more established microherd and humus content (aged,recycled,root size, ingredients etc) who may then have a more dramatic effect on the stable form of nutrients/needs of water etc etc.
Just like some also say that they just water less or @ all the last weeks of flowering,to get that same loss of color of fan leaves and better taste.
My point of view is it depends on the how’s and what’s of many things when talking about growing.

 

[*Journeyman*]

dont forget to take into account what is "available" and what is not.

So true. I recently learned a bit about soil testing and labs use 2 different methods. The best IMO uses organic acids, like root exudes, as the extracting agent and results show what's available to plants and not necessarily what's in the soil as other tests will show when using something like nitric acid for example.

As for flushing using containers to me it means using an excess volume of pure water to remove or reduce components in the medium that can be taken up by the plant and also possibly increasing the watering frequency over the norm. When using a reservoir to me it means maintaining the same feeding/watering schedule but making much more frequent res changes of pure water. In organics, the way I define it, it means doing nothing different.

 

[Microbeman]

^ right... but think about it... we are talking about pot plants. A pot plant's root system only goes so deep. So, when dissolved salts and minerals are washed down, beyond the reach of the root system, those salts are, in fact, no longer available to the plant. Not all nutrient is locked in the microherd, of course, otherwise run-off from soil would yield ZERO nutrient content... but of course there IS nutrient content in soil run-off... so that negates the theory that all ionic nutrient is held within microbes. So when the dissolved salts are moved beyond the reach of the root system, this is the same, exact effect as flushing a plant in a container... the dissolved salts are moved away from the reach of the root system. No?

Microbes hold nutrient... but this doesn't mean they hold all of the ionic nutrient in the medium. No? What I hear from some people in here is that organic soil needs no flushing because ALL of the ionic salts are locked up in microbes. I very respectfully, but heartily disagree with that assertion. If it were true that all the ionic salts were locked in microbes, then you would not be able to get any measurable salts from water run through organic soil. Since there are measurable salts in organic soil run-off.. it's pretty safe to assume that not all salts are locked in microbes. No?

I'm both trying to understand your point-of-view and trying to make you understand ours. This is talking shop, it's constructive as long as people don't take it personally... keep this in mind.

First of all I apologize in advance if I have missed something.

1/ I'd be interested in a definition of the soil used in the above statement. I'm assuming this is with guano topdressed as the only amendment(?)

2/It would be interesting to see some citations or recorded data to support your statements of the
"measurable salts in organic soil run-off."

3/ I am assuming you are using an EC/TDS meter in your measurements of 'ionic salts' contained in the run-off. I'm not sure if you are aware but there are many of us in the organic growing field who have been questioning the efficacy of these meters in this application, that is measuring of ionic salts in a liquid with suspended organic matter (OM). The propensity for the readings of the electrical current to be skewed by OM particles is very high. Because of this most have discontinued using the EC/TDS meter for attempting to accurately measure ionic salts in an OM slurry. Don't get me wrong; the meter has many practical uses, I use it to test my water all the time and the meters are great for carbon mapping.

I researched this fairly thoroughly some time ago and had an online discussion with some fairly knowledgeable people (sorry, I have yet to locate my notes). I was directed to seek the ultimate information from The US Composting Council at http://www.tmecc.org I ended up contacting one of their top experts to get his opinion on this and here is his response.
"EC test is a measure of the conductivity of a solution. Two poles are inserted into the solution with known separation and the amount of electricity or current passing from one pole to the other via the solution is measured. In my opinion, it is not a very elegant or reliable test method as there are so many potential interferences ... especially when the main interest is to approximate the water-soluble salt (NaCl) ion concentration of a solution.

Thank you,
- Wayne

Wayne H. Thompson - Extension Program Specialist, Biofuels Agronomist
Texas AgriLife Extension Service
Soil and Crop Sciences Department - Texas A & M University
434 Heep Center - Mailstop 2474
College Station, TX 77843-2474"

 

[Microbeman]

What I hear from some people in here is that organic soil needs no flushing because ALL of the ionic salts are locked up in microbes.

Just to be clear; I have not said this. Although there is undoubtedly some nutrient sequestered in microbial mass, the lion's share would hopefully be sequestered in OM/humus.

 

[VerdantGreen]

doesnt the ability of a soil to hold nutrients depend on its content? humus will help hold minerals in the soil and i believe clay particles hold a negative charge that also allows them to hold onto nutrients.
sandy soils wih low organic matter/humus content tend to be the ones that leach out nutrients fastest from my experience.

V.

 

[Grat3fulh3ad]

doesnt the ability of a soil to hold nutrients depend on its content? humus will help hold minerals in the soil and i believe clay particles hold a negative charge that also allows them to hold onto nutrients.
sandy soils wih low organic matter/humus content tend to be the ones that leach out nutrients fastest from my experience.

V.

=]

 

[vonforne]

doesnt the ability of a soil to hold nutrients depend on its content? humus will help hold minerals in the soil and i believe clay particles hold a negative charge that also allows them to hold onto nutrients.
sandy soils wih low organic matter/humus content tend to be the ones that leach out nutrients fastest from my experience.

V.

That was kinda of my point with the cave example. In Texas the soil is poor and the run off would be greater and the caves are primarily limestone.

So, if I am using a `Living organic soil`,would I need to ´flush`?

I do not believe so but then again I am not measuring or being scientific. That s why we have Uncle MM. Now when I used bottled nutrients.....just a few years ago like FF I made sure to rinse the ole soil out. But now I have no need to and have no taste or burning problems.

 

[*Journeyman*]

doesnt the ability of a soil to hold nutrients depend on its content? humus will help hold minerals in the soil and i believe clay particles hold a negative charge that also allows them to hold onto nutrients. Sandy soils with low organic matter/humus content tend to be the ones that leach out nutrients fastest from my experience.

V.

Yes clay is good for that and there is some research on the benefits of using pyrophyllite (otherwise known as thermophylic) clay in hydroponic systems such as...

A comparison of two growing mediums, one sand with clay colloids, and the other a hydroponic solution, each with an equal portion of soluble salts showed that the absorbed ions of the clay resulted in greater plant growth. Clay surfaces absorb large amounts of plant nutrients without any appreciable change in the osmotic concentration of the growing medium or fluctuation of pH. Additionally, clays increase the cation exchange capacity of the substrate.

But yeah humus is the key in soil systems but also has to do with the form of the nutrients being applied i.e. salts or organic compounds. For example...

...plants utilize a small percentage of the total soluble fertilizer applied. In the case of phosphorous, the application of soluble P creates a shift in the chemical equilibrium with about 1/3 of the fertilizer locking up with positively charged metal ions in the soil. About 1/3 runs off as a water pollutant and the rest of it becomes available to the plant, ironically, by microbial activity. As the combination of harsh chemicals actually reduces soil humus and harms microbes, the process becomes self-defeating

I'm referencing 'Rethinking Phosphate Sources A Geo-Biological Approach' by Lawrence Mayhew and this applies to soil but still a good article in general.

The ability for soil to hold onto nutrients depends on first the composition of the soil and secondly the form of the nutrients applied. Also root hairs in sandy soils tend to simply fry.

So if you're talking about flushing then hell yeah in the quoted situation outlined above

 

[*Journeyman*]

Here's another article by Lawrence Mayhew I think worth reading...'Humic Substances as Agronomic Inputs in Biological Agriculture Systems: a Review'. A bit off track from the topic of flushing but from what I understand flushing is necessary and/or important in some situations but not others and partly dependent on the form of nutrients applied but also the medium.

 

[MickTheBrag]

you need to get rid of some of the salt build up during flowering. a couple of one day flushes does the job.
then next day get back on the nutes as usual.


and if you dont get what iam saying then thats cool.

 

[xmobotx]

I've read repeatedly that a "flush" is a proportionately heavier watering aimed at rinsing excess nutrient/solution/buildup/whatever from container mixes

some alternating feeding w/ water-only might consider their water-only watering a flush. I think that's something of a stretch though.

No doubt a flushing of sorts occurs in nature

in organics:

botlled nutes organics - i suppose one could think of a flush (watering to runoff/NOT alternating w/ water only) as rinsing out solution from previous waterings

w/ "true" organics OTOH - watering to excess (as 'flushing') could possibly be viewed as diluting the nutes available in the current state. But, its not goin to "flush" in the sense of rinsing out bottled nutes. And, it could cause a dangerous imbalance in some setups.

in a system where you add dry ferts to a relatively "true" base, withholding feerts would accomplish the same tasks as a water flush is intended (to late flower stage) - or FTM where dry ferts were top dressed to a 'foodless' (there's always going to be something in most mediums) medium (as by discontinuing the feeding for late flower)

in senescence a plant will (varying based on strain & conditions) cannabalize itself. I also believe the plant 'knows' its going to die (and that this is part of why it cannabalizes itself.) But, I have seen plants growing in outdoor soil where nutes are basically unlimited (this specific situation) which still enter senescence and still cannabalize themself.

So to reiterate... i have had WAY more probs with soil being too wet vs too dry.

The best way to grow i have found (indoors) is to use the bio box (obbt) method. This way you let the medium dry right out in the last week or two and watch the leaves turn brown and crispy but leaving sweet, sticky and nicely cured bud from the minute you chop!

i am curious about this drought concept - and can see where it would be easy to implement w/ a OBBT system - possibly another merit of the system

 

[dub 6]

^ right... but think about it... we are talking about pot plants. A pot plant's root system only goes so deep. So, when dissolved salts and minerals are washed down, beyond the reach of the root system, those salts are, in fact, no longer available to the plant. Not all nutrient is locked in the microherd, of course, otherwise run-off from soil would yield ZERO nutrient content... but of course there IS nutrient content in soil run-off... so that negates the theory that all ionic nutrient is held within microbes. So when the dissolved salts are moved beyond the reach of the root system, this is the same, exact effect as flushing a plant in a container... the dissolved salts are moved away from the reach of the root system. No?

Microbes hold nutrient... but this doesn't mean they hold all of the ionic nutrient in the medium. No? What I hear from some people in here is that organic soil needs no flushing because ALL of the ionic salts are locked up in microbes. I very respectfully, but heartily disagree with that assertion. If it were true that all the ionic salts were locked in microbes, then you would not be able to get any measurable salts from water run through organic soil. Since there are measurable salts in organic soil run-off.. it's pretty safe to assume that not all salts are locked in microbes. No?

I'm both trying to understand your point-of-view and trying to make you understand ours. This is talking shop, it's constructive as long as people don't take it personally... keep this in mind.

great thread. I haven't read all of it yet but I wanna jump in here. this is a good point you pose, but as those salts move past the roots, aren't they replentished at the top of the soil and continue in a trickle-down effect? therefore in mother nature salts are always present. possibly in varying levels during the seasonal cycles of the area.

with that being said, and from what I gathered from this thread thus far, I take the proper flush in a synthesized environment to be giving the plant nute-less water for the last weeks and excess waterings in the last 5 days to wash out the salts, keeping the medium wet the entire five days to disable the microherd. then leave the plant in the dark until the medium dries so photosynthesis doesn't resume when the microherd picks back up. once dry, chop.

what do u guys think about that idea?

 

[SilverSurfer_OG]

i am curious about this drought concept - and can see where it would be easy to implement w/ a OBBT system - possibly another merit of the system

Probably not the right thread to get into this but yeah the obbt is built to implement a flush, starve and feed cycle... in a very user friendly way. Also the air being pumped into the medium helps keeps it evenly moist.

As i understand it the drought at the end forces the plant to use up all available nutes in the medium and then the sugars in leaves/roots. A dry medium will stop absorbing nutes.

It is quite amazing to see each leaf in turn have the life sucked out of it... but of course the drought isnt started until i have watered for a week or so with just water.

So say there is too much N in yer mix and its week 6 of flower. To keep watering is to allow the plant to take in more. Drying her out starts the curing process. This is all subject to plant vigour/thirst and pot size.

In a smaller pot would maybe be inclined to flush much later...

Flushing is important IMHO. Just not at the end.

 

[RNDZL]

just to clarify

what is the "non" marijuana related term for flushing

what do the community of botanist and horticulturists say !?!

is it applying 3x the volume of water to the medium?

 

[RNDZL]

if applying 3x the volume in water is what a traditional flush is I have never ever flushed a medium in many years of growing unless the plant was in crisis due to dysfunction in that medium

rockwool, promix, outdoors, hydroponic aeroponic organic or otherwise


flushing in traditional gardening terms is cleansing the medium of unwanted elements


the real question is, how do i get my plants to use up their own stores as they near harvest so there is no excess built up of chlorophyll and perhaps other elements. Now while i no very little on plant or ot biology i know it leeches uglies outta the soil like uranium. i dont want to go off on a tangent continue to read below and I solidify my point.

now ppl argue that organics does need to be flushed

but i dont see any good organic farmers feeding heavy doses of fish emulsion to their plants 3 weeks before harvest .. try it tell me how it tastes

in fact they limit the feed to organic compound sources to avoid non organic contaminants in the plant

what i mean the point is we have all missed the fucking point


flushing is a fix for pollutants in your medium or build up of shit

THAT YOU HAVE MOST LIKELY FED TO THEM


we are indoor gardening here

this is controlled environment

what all good ganga farmers organic or not know is that your control the uptake of nutrient the minute you take control of providing it

i simply start given them no feed all water and if i did my job right ill time it a cpl weeks before harvest and there will be no residual nutrients for them to feed on and they will feed of themselves

but most people are overfeeding the plant in hopes of changing the world in one grow

nature does not do well will more more more

it requires balance

you don't need to flush anything if you have properly fed your plants and stopped feeding them at the right times

no matter the medium or method

growing good weed is far less complex than ppl make it

 

[DARC MIND]

rndzl
again, it all depends what media or soil you grow in and how you grow.
to me flushing is just watering excessively, the choices of going about the hows and whats of growing will determine if and how much soluble nutrients will leach or if flushing is even needed. nature doesnt topdress with gouno of feed bottle nutes, so when it does rain lots, not much is being "flushed", everything is cycled in one big circle.

some dont flush @ all or water excessively, some may work with better structured soils who hold and cycled nutrients and (were youll find me) feed the soil in a balancing act while others try to feed the plant.

 

[Grat3fulh3ad]

I find the best strategy, whether using organics or refined minerals or any combination, is to avoid ever feeding your plants any contaminants or unwanted elements...

I agree with RNDZL "if applying 3x the volume in water is what a traditional flush is I have never ever flushed a medium in many years of growing unless the plant was in crisis due to dysfunction in that medium"

If I cannot simply stop adding nutrient when growth has stopped and ripening is occurring, and have the plant finish right, then I used way too much nutrient during the grow.

I know this is in the organics forum, and I haven't grown using organic nutrient sources for quite some time, but the end goal is the same... and the path to arrive there does coincide some...