When should I flush?

[Blowreefer]

Hello fellow growers i have a blue cookie and runtz plabt both in week 6 of flower both grown in 5 gallon buckets in soil given molasses since week 5 of veg, and botanicare pure bloom pro during flower i have just started overdrive last week also the runtz has fat stacked up buds and a huge cola and the blue cookie buds are nice size but a little spaced out im wondering when is a good tome to flush my plants if all of my hairs havent turned orange yet every other bud has a little orange on it but maybe only 30 % of the plant total, the runtz has leaves yellowing out near the bottom of the plant (as seen in pics) please help all info appreciated, p.s. sorry for the shitty camera quality

 

[Old Salt]

Flush two to two and a half weeks before harvest, then keep feeding them until the harvest.

 

[Southpw]

Flush two to two and a half weeks before harvest, then keep feeding them until the harvest.

Really? I never heard of that. The point of flushing is to rid the plant of any of the nutrients and make plant use it up during final stages to have a "Clean" bud when harvesting. Or are you referring to "keep feeding" by means of water only?

Blowreefer.... I am at same stage as you and plan to start flushing on 2 weeks and harvest in 1-2 weeks after that.

Some people are stating there is no need to flush.... But I will flush just to be safe.

 

[Southpw]

"Feeding them" with just water for 2 weeks IS the process to flush your plants..

 

[Blowreefer]

Thanks southpaw

 

[TurboBucket]

#no flush. Especially if your in organic soil. Flushing doesn't remove anything from the buds. Just more broscience.

 

[Old Salt]

Really? I never heard of that. The point of flushing is to rid the plant of any of the nutrients and make plant use it up during final stages to have a "Clean" bud when harvesting. Or are you referring to "keep feeding" by means of water only?

Blowreefer.... I am at same stage as you and plan to start flushing on 2 weeks and harvest in 1-2 weeks after that.

Some people are stating there is no need to flush.... But I will flush just to be safe.

"Feeding them" with just water for 2 weeks IS the process to flush your plants..

Most of our most experienced growers no longer flush the way you stated. The purpose of the flush as I outlined it is to clear the salts from the root area. This allows the roots better access to the nutrients in the soil for the last two weeks.

The method you've described was very common several years ago. Some still do it that way. The supposed purpose was to pull the synthetic nutrients out of the plant to improve the taste. This has been proved to be erroneous. There is no difference in the taste at all, and you get a bigger harvest if you don't flush.

 

[Emilya Green]

"Feeding them" with just water for 2 weeks IS the process to flush your plants..

no... no and again no.... we do not flush our plants. It is counter productive and does nothing to help the end product except make it smaller and less potent. You can't flush a plant anyway... all you can do is starve it to death.
we flush the soil, not the plants. The concept of flushing plants has been debunked. We flush the soil to clean it. It is not to clean up the bud because we now know that any amount of flushing or starving at the end, will not change the flavor of the cured bud. We flush the soil 2 weeks from the end to remove built up salts and left over nutes that are getting in the way of full water uptake, and then after that we feed them hard right up till the end with finishing nutes. If you want big huge rock hard buds with lots of trichomes, don't starve your plants at the end. Give them this proper 3x flush right before the final bud swell in the last two weeks and you will be amazed what happens.

 

[Southpw]

Thank you all for that info. I will not be flushing now that I have read this

 

[bobrown14]

OOH ooh ooh, I know this one.... every time you go the the bathroom?

What are we flushing again?? I'm confused.

 

[bobrown14]

There's a thing in soil called CEC or cation exchange capacity.

About the only thing you're gonna wash out of a soil that has any amount of CEC is an over abundance of soluble Nitrogen. Be it from composted manure or chemical fertilizer.

Anyone that has excess N in soil in flower, gonna gave grassy hay flavored weed may as well flush and add all that Nitrogen back into our drinking water supply. That should be beneficial to ....... algae.

Thats all I'm gonna say on the subject. I promise. lol

 

[Blowreefer]

Im not flushing anymore

 

[Emilya Green]

when and if your plants stagnate because of this determination to not ever flush, please always consider a 3x flush to clear the salt. Salt is a real thing that builds up in any synthetic grow and it can and often does cause lockouts. Without a flush in the last 2 weeks after feeding heavily up until that point, all the while building up salt, you ARE restricting your water uptake to some degree, and to whatever degree that happens to be, your buds will end up that much smaller.

And Bob... to measure your CEC the first step is to wash the soil of any salts that interfere with the reading... because salt is being bound by those ions too. Salt can be washed (flushed) out easily, thus clearing the way for more cation exchange. Everything else you said about N is true, but at this stage of the grow other minerals are being held too. Your bringing CEC into this as an argument against flushing is confusing, maybe you should explain further?

 

[bobrown14]

CEC is a chemical bond. You cannot break that bond with water. H2o has no way to chemically break those cations from the soil particles. It's just chemically not possible.

As mentioned, yes excess N can be washed away as its got nothing to bond to because it is EXCESS and there's no soil particles to bond to. There's probably a few anions that can wash out but very few. Soil HIGH in SOM (soil organic matter) and high CEC will have very little excess to leach away.

Cannabis grows better with excess Ca (that it not soluble) and low N so we are better off using less N than more of it. So waste not want not and its cleaner for our environment.

I get my soil tested at a lab. I don't flush. I use my soil over and over with good result. The soil is actually tested for salt build up too. This is an issue with farmers that use chemical and natural fertilizers, the excess N causes problems with the fresh water supply eventually causing health issues.

There are ways to mitigate excess N without the use of water to wash it away.

Planting a cover/companion crop is one that a lot of no-till farmers use in fields and in containers. You can lock up N by adding in some material to your soil that needs to be broken down by the composting process. As N is needed by the microbes for a food source to do the composting.

An example of what I do is add in 1/2 cup of fresh cut Horsetail fern to my holes at transplant with some EWC. That material will need to break down and the microbes will use N to do that. I don't really like leafy cannabis plants. If it was tomato or bean or something else I would just leave it be. So that N gets partially used up in the compost process.

I know yes sure leaching off the excess N is an easy fix. Best to not over apply.

We need to be somewhat sensitive of our farming practices and its affect on our environment. I grew up in a time when the health of our environment was a big deal.

Here's read on excess fertilizer and its affects on nature - note its from the EPA of all places - its an easy read:

The Sources and Solutions: Agriculture | US EPA

 

[Emilya Green]

There are ways to mitigate excess N without the use of water to wash it away.

... as well as the salt that builds up in a synthetic grow. You have found a better way that does not build up salt, but our OP is feeding synthetically and needs to know that salt lockups are a thing in his type of grow, and a thing that can and should be avoided.

 

[bobrown14]

I understand now.

I get lost in the salts.

 

[shortbritches]

Why flush if growing organic . I do not add nutes when growing . The nutes,fish meal,alfalfa meal,bat guano etc are in soil when I plant .and I never add nutes just worm tea. So why flush. If some one can give me a reasoned answer I would consider it.

 

[Emeraldo]

OOH ooh ooh, I know this one.... every time you go the the bathroom?

What are we flushing again?? I'm confused.

Oooh, Bob! There you go again!

 

[bobrown14]

Glad I could help.

I'm just passing on the science.

SOM + CEC in soil = nothing or very little will leach out.

check it out:

"Cation exchange capacity (CEC) is the total capacity of a soil to hold exchangeable cations. CEC is an inherent soil characteristic and is difficult to alter significantly.

It influences the soil's ability to hold onto essential nutrients and provides a buffer against soil acidification. "


Cations are part of the nutrients in soil.

They have a positive charge and are attracted to soil particles and form a chemical bond. This is why its difficult to use water to leach out nutrients. IF you have excess cations then yes leaching will occur. Again very difficult in soil with high CEC and a decent amount of SOM (soil organic matter).


The influence is a chemical bond. The higher the CEC and soil organic matter the less leaching you will get due to the chemical bonds made with soil particles and nutrients.


Conventional soil (chemical fertilizers) and organic soil are the same when it comes to CEC and leaching nutrients.

Folks that grow in mediums OTHER than soil can benefit from "flushing" growing medium of excess not used nutrients prior to infusion (or whatever its called) a fresh round of soluble nutrients. These are not soil based mediums so they have very little CEC and SOM. So nothing for the soluble nutrients to hold on to.

There are scientists that study this stuff for a lifetime job. It's an important role, as this information is used in food production.

We cannabis farmers can take advantage of the shared knowledge.

I have more. lol

 

[TorturedSoul]

... as well as the salt that builds up in a synthetic grow. You have found a better way that does not build up salt, but our OP is feeding synthetically

So OP posted the thread in the wrong section of the forum?