Flushing: The ideal time to flush!

[Dutchman1990]

Hello everyone!

So as my girls are nearing to an end I have read and read about flushing and gotten the best knowledge I could from those sources... now I’m turning to the great community here at 420 to get some further opinions on when the BEST time to start flushing and for how long you flush your plants! This is going to be an informative thread so all growing mediums are welcome and all knowledge is greatly appreciated!

So I’ll get things going... I’m growing in Promix a soiless medium. My thoughts would to be to treat this as a “light flush” mix and flush for 1 week approximately to harvest end. That being said it would be roughly when 30-40% of trichs are cloudy? - correct me if I’m wrong here please!!

In soil they recommend a 2 week flush and for hydro Up to a 1week flush.

So here is my question in regards to this:

1- Should I begin flush on the plants that are grown in a promix medium sooner than 1 week?

2- Should the flush be done once and allow pot to dry then harvest ?

3- Finally .... the trichs and red hairs on the flowers should be approximately where ( ** hairs 50-60% and trichs 30-40% cloudy ?)

Thanks so much everyone for your input and I’m excited to see what else can be brought to the table!!

- Dutch

 

[Orlando Scout]

Ill tag along I've been wondering the same.

 

[KingJoe83]

It’s a really hard thing to say this is what you should do but to my best knowledge I’ve come to this

Organic soil no need to flush

Synthetic nutes soil is flush 7-14 days depending how heavy you feed her

Coco 1-2 days

Hydro water culture systems none needed .

This is my best undersnding . And if you think about it makes sense .

As far as harvest time goes you want to look into if it’s a Indica dominate strain or sativa sativas are to be harvested if not mistaken more clear cloudy . And Indica more amber . And depending on how much you like sleepy the more the better .

Again I’m still learning myself but this is my best understanding .

Hope that helps

 

[MrSauga]

Here's an interesting article to read. Another member led me to this.
A critical look at preharvest flushing

 

[Papageno]

Not going to reiterate as the important stuff is there already. The main thing to note is the medium AND style matter.

The reason I am posting isn't that the info is wrong rather poorly stated.


You can't flush organic mediums. You can flush nutrients even organic ones from a medium but organic mediums are constantly slow releasing nutes. You can't flush that. You can try and it is just back up and running next day.

Unless you are running hydro.

The point to coco is it is an organic medium which absorbed nutes in basically the same way a normal soil works only with more control. Both a dead soil and soilless mediums can be flushed rather easily.

I flush hydro 1 day with heavy sugar and enzyme then go into the long night.

 

[MrFortwenty]

Correct time to flush? If you're flushing because you think it'll make your smoke smoother because you won't be smoking nutes, that is total bro science. Finally this was tested and those of us that thought this was stoner science can start to move onto things that matter. Now only if more studies can come out to shoot down some of the other crazy "rules" people seem obligated to follow.

"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."

Irrigation Management Strategies for Medical Cannabis in Controlled Environments

 

[bobrown14]

On Flushing... complete bro stoner science for anything but HYDRO. Flushing hydro systems is cleaning out the medium has nothing to do with plant growth/taste/chemicals nada.

Just ask yourself, what are you trying to accomplish by adding extra water to your growing medium??

Chemicals are bonded to the elements that make up the soil. The only extra chemicals in the soil that "might" run off is excess Nitrogen. It's in excess because the plants didn't up take it. So it's not in the plant so you cannot wash or flush or whatever is it this flushing business is all about.

This is proven science to btw. It doesn't work. What happened to all the oil that was spilled in the Gulf with huge ass fire and all?? The oil was eaten by bacteria. That's how we clean soils that have had a chemical spill. Not washing the chemical away with lots of water. That's a myth from some where. There's a thing called chemistry, this whole idea about flushing falls flat on its face when we bring chemistry into the equation.

I wasn't very good at chemistry but when I herd of flushing that just sounded very odd, and it is.

@Dutchman1990, the reason why some folks get results from "flushing" is a lot more likely due to the fact that the plants have been chronically under watered thruout the life cycle. The 2 weeks before harvest with a "flushing" routine we actually are giving the plant the proper amount of water right at a very important time coming down the stretch into harvest.

Plants have a way of storing energy in the fan leaves to be used later when the plant grows flowers to reproduce. So plain water the last 2 weeks is just what the plant needs and lots of it.

In your journal I pointed out that your ladies look like they are thirsty.

My plants in the last month the flower cycle drink about 1 gal of water per plant every day all the way down to the end. Your plants look great and wood benefit from having extra water. You can call it flushing. I see it as giving the plants enough water to finish.

Think about it, if flushing worked, what wood happen to the soil after every rain fall outside in your garden?

Extra nitrogen in the form of chemical fertilizer or animal poop compost will wash out into the streams and fresh water supply. But that has no effect on the plants growing in the soil.

 

[Dutchman1990]

Excellent response @bobrown14
I actually took some info that @MrSauga gave me above.
Flushing Explained.
This led me to not flushing my plants I gave WW1- Feed yesterday, I am letting her dry out and cutting her for harvest !!

On Flushing... complete bro stoner science for anything but HYDRO. Flushing hydro systems is cleaning out the medium has nothing to do with plant growth/taste/chemicals nada.

Just ask yourself, what are you trying to accomplish by adding extra water to your growing medium??

Chemicals are bonded to the elements that make up the soil. The only extra chemicals in the soil that "might" run off is excess Nitrogen. It's in excess because the plants didn't up take it. So it's not in the plant so you cannot wash or flush or whatever is it this flushing business is all about.

This is proven science to btw. It doesn't work. What happened to all the oil that was spilled in the Gulf with huge ass fire and all?? The oil was eaten by bacteria. That's how we clean soils that have had a chemical spill. Not washing the chemical away with lots of water. That's a myth from some where. There's a thing called chemistry, this whole idea about flushing falls flat on its face when we bring chemistry into the equation.

I wasn't very good at chemistry but when I herd of flushing that just sounded very odd, and it is.

@Dutchman1990, the reason why some folks get results from "flushing" is a lot more likely due to the fact that the plants have been chronically under watered thruout the life cycle. The 2 weeks before harvest with a "flushing" routine we actually are giving the plant the proper amount of water right at a very important time coming down the stretch into harvest.

Plants have a way of storing energy in the fan leaves to be used later when the plant grows flowers to reproduce. So plain water the last 2 weeks is just what the plant needs and lots of it.

In your journal I pointed out that your ladies look like they are thirsty.

My plants in the last month the flower cycle drink about 1 gal of water per plant every day all the way down to the end. Your plants look great and wood benefit from having extra water. You can call it flushing. I see it as giving the plants enough water to finish.

Think about it, if flushing worked, what wood happen to the soil after every rain fall outside in your garden?

Extra nitrogen in the form of chemical fertilizer or animal poop compost will wash out into the streams and fresh water supply. But that has no effect on the plants growing in the soil.

 

[bobrown14]

The "flushing explained" thread for sure "sounds" sciency. Problem I have is I grow organically without chemicals. IF that article was all truth, how do my plants even live??

It's written like - if you dont flush, your plants are somehow missing something important down the stretch or worse.

Example:

"You can see this by the yellowing and later dying of the mature fan leaves from the second day on after flushing started. Developing leaves, bud leaves and calyxes don’t serve as sources, they are sinks. Changes in those plant parts are due to the deficient immobile elements which start to indicate on new growth first.

Unfortunately, several metabolic processes are unable to take place anymore since other elements needed are no longer available (the immobile ones). This includes processes where nitrogen and phosphorus, which have likely the most impact on taste, are involved. "

The first paragraph quoted doesn't even make any sense to me. There's a thing being overlooked here.

Explain what this is and/or even how this could happen IN SOIL:

"deficient immobile elements"



Its written like the only plants that have yellowing leaves are plants that have been flushed. I find that very odd, and also find that MOST (but not all) chem growers don't get yellow leaves or whats called "senescence" down the stretch due to the plant having excess nitrogen available for uptake which gets stored in the plant for use later on. Plants will gladly use whats available at the roots as well as whats available in the plant itself. Excess N grows big green plants.


Now lets talk about those "immobile elements".

Here's a quote from Cornell University:

"

• Plants require 18 essential nutrients to grow and survive, classified by their importance into macronutrients (C, H, O, N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn, Mo, Cl, Co, Ni).
• Nutrients may be mobile or immobile in the plant and in the soil, which influences redistribution of nutrients and display of deficiency symptoms, and the fertilization of crops.
• Nutrient demands change throughout the life of the plant, in general increasing during vegetative growth but decreasing during reproductive development.
  

I"m not buying Ca as a immobile nutrient being a problem during flowing. If its available to the roots Ca will be translocated to all new growth. It's how plants live. Because one or more nutrients are immobile doesn't mean flowers wont get bigger or continue to grow.. or worse we somehow wash away those minerals with a "flushing" procedure.


So counter intuitive is what I read.

Immobile elements - how do they get into the plant?

A: roots, some plants can absorb them thru leaves (kelp is an example).

Do they stop being absorbed by the plant once the plant begins its reproductive stage??

A: No, roots are still a primary source for nutrient uptake. That happens until we cut the plant away from its roots at harvest time.

^^^ This is how plants live.


My take and I've said it many times:

Flushing nothing more than watering the plant. As long as there are drain holes in the container, all we are accomplishing is watering the plant. In most instances cannabis plants in containers are under watered. So a nice excess of water right at the time the plant needs it most is the benefit.

I call flushing "proper watering".

Here's a good experiment. Take a plant in a container in flower and put a large drain tray under the plant/pot. Water in 2 gallons or even 3 gallons all at once. Let the extra water sit in the tray. Note how long it takes for the plant to re-absorb the excess water. I bet its going to be a lot faster than you initially thought.


My point isn't to bang on anyone. My point is that there's some weird faux science/biology going around and it seems pretty prevalent in the cannabis world for some reason.

I tend to see things written that don't seem quite clear or don't make sense, then I look it up and NOT in the Cannabis Grow Bible.

When I see something like:

non-facts followed by a bunch of science that has nothing to do with the initial "non-fact", it tends to raise questions about that "non-fact" thing. Food for thought.

Example:
"Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival".

That ^^^ boggle's the mind.

 

[Dutchman1990]

@bobrown14
Awesome write up and I love the explaintions and definitions!! Excellent info! I have come to the decision I am feeding straight until harvest to minimize any end stress! We want the plants to survive and be their strongest at the finish line!

I also got a ton of new trich photos and plant photos this evening so she’s getting close now !! No flush and her leaves are yellowed and finishing you can tell she’s on her final push !

 

[MassMedMan]

Very rarely have I been accused of being scientific. But, however, my rule of thumb on flushing ( no offense to the excellent responses before me) is,,, if it's yellow let it mellow if it's brown send it down.

Stay lifted bro

I'll be touring soon.....

 

[beez0404]

I grow some plants in Pro Mix BX, some with Fox Farm Nutrients. When a plant in Pro Mix BX is showing me about 80-90 % cloudy crystals I cease with the nutrients. For the next 10-14 days the plant will receive all the water she wants. I stop watering 4 days prior to harvest day.

 

[Archiweedies]

Here's an interesting article to read. Another member led me to this.
A critical look at preharvest flushing

Do yourselves a favor and read this as it was recently passed to me from @InTheShed and fully supports what Bob is saying. It’s a short but educated and educational writing.

The "flushing explained" thread for sure "sounds" sciency. Problem I have is I grow organically without chemicals. IF that article was all truth, how do my plants even live??

It's written like - if you dont flush, your plants are somehow missing something important down the stretch or worse.

Example:

"You can see this by the yellowing and later dying of the mature fan leaves from the second day on after flushing started. Developing leaves, bud leaves and calyxes don’t serve as sources, they are sinks. Changes in those plant parts are due to the deficient immobile elements which start to indicate on new growth first.

Unfortunately, several metabolic processes are unable to take place anymore since other elements needed are no longer available (the immobile ones). This includes processes where nitrogen and phosphorus, which have likely the most impact on taste, are involved. "

The first paragraph quoted doesn't even make any sense to me. There's a thing being overlooked here.

Explain what this is and/or even how this could happen IN SOIL:

"deficient immobile elements"



Its written like the only plants that have yellowing leaves are plants that have been flushed. I find that very odd, and also find that MOST (but not all) chem growers don't get yellow leaves or whats called "senescence" down the stretch due to the plant having excess nitrogen available for uptake which gets stored in the plant for use later on. Plants will gladly use whats available at the roots as well as whats available in the plant itself. Excess N grows big green plants.


Now lets talk about those "immobile elements".

Here's a quote from Cornell University:

"

• Plants require 18 essential nutrients to grow and survive, classified by their importance into macronutrients (C, H, O, N, P, K, Ca, Mg, S) and micronutrients (B, Cu, Fe, Mn, Zn, Mo, Cl, Co, Ni).
• Nutrients may be mobile or immobile in the plant and in the soil, which influences redistribution of nutrients and display of deficiency symptoms, and the fertilization of crops.
• Nutrient demands change throughout the life of the plant, in general increasing during vegetative growth but decreasing during reproductive development.
  

I"m not buying Ca as a immobile nutrient being a problem during flowing. If its available to the roots Ca will be translocated to all new growth. It's how plants live. Because one or more nutrients are immobile doesn't mean flowers wont get bigger or continue to grow.. or worse we somehow wash away those minerals with a "flushing" procedure.


So counter intuitive is what I read.

Immobile elements - how do they get into the plant?

A: roots, some plants can absorb them thru leaves (kelp is an example).

Do they stop being absorbed by the plant once the plant begins its reproductive stage??

A: No, roots are still a primary source for nutrient uptake. That happens until we cut the plant away from its roots at harvest time.

^^^ This is how plants live.


My take and I've said it many times:

Flushing nothing more than watering the plant. As long as there are drain holes in the container, all we are accomplishing is watering the plant. In most instances cannabis plants in containers are under watered. So a nice excess of water right at the time the plant needs it most is the benefit.

I call flushing "proper watering".

Here's a good experiment. Take a plant in a container in flower and put a large drain tray under the plant/pot. Water in 2 gallons or even 3 gallons all at once. Let the extra water sit in the tray. Note how long it takes for the plant to re-absorb the excess water. I bet its going to be a lot faster than you initially thought.


My point isn't to bang on anyone. My point is that there's some weird faux science/biology going around and it seems pretty prevalent in the cannabis world for some reason.

I tend to see things written that don't seem quite clear or don't make sense, then I look it up and NOT in the Cannabis Grow Bible.

When I see something like:

non-facts followed by a bunch of science that has nothing to do with the initial "non-fact", it tends to raise questions about that "non-fact" thing. Food for thought.

Example:
"Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival".

That ^^^ boggle's the mind.

Well said! The longer I grow cannabis the more I learn. The more I learn to do and NOT to do. It’s tough being a new grower because there is so much info overload and so much bad info out there. Everyone has a different way of doing it. I’ve been growing for two years and maybe I’m a slow learner but I’m just now really educating myself about what this plant really needs. It’s needs are really simple but we just make it harder on ourselves at times.

My path has led me to try organic gardening next and I am learning how the plant uses the nutrients, when certain nutrients are needed, etc. rather than just reading a bottle of nutes and mindlessly mixing em’ up the way the gro shop guy or websites say to. My two cents.

Pics look great Dutch!

 

[Dutchman1990]

Do yourselves a favor and read this as it was recently passed to me from @InTheShed and fully supports what Bob is saying. It’s a short but educated and educational writing.



Well said! The longer I grow cannabis the more I learn. The more I learn to do and NOT to do. It’s tough being a new grower because there is so much info overload and so much bad info out there. Everyone has a different way of doing it. I’ve been growing for two years and maybe I’m a slow learner but I’m just now really educating myself about what this plant really needs. It’s needs are really simple but we just make it harder on ourselves at times.

My path has led me to try organic gardening next and I am learning how the plant uses the nutrients, when certain nutrients are needed, etc. rather than just reading a bottle of nutes and mindlessly mixing em’ up the way the gro shop guy or websites say to. My two cents.

Pics look great Dutch!

Hey Archi and thanks! That link is actually posted above and in my journal ! It is a great read and led me to not flushing to keep stress minimized before harvest to keep the girls the strongest in their last days!

Hope all is well pal and I got a busy day of harvesting WW1 today ! Woohoo !

Keep em green fam!

 

[Chris Scorpio]

 

[Dutchman1990]

Thanks Chris !

 

[Cushblah]

I'm in on this. Bobbrown your description makes perfect sense to me, I was told that you can 'flush' for 1 or 0 days and the plant has the 'metabolism' or whatever to make itself smooth to smoke. No need for flushing basically. I 'flushed' 6 babies for 1 day and smoke was so smooth. Good drying is the key to that. Anyone wants a look at my journal im 3 weeks away from harvest have 20 something on go at the min

 

[Papageno]

I stopped watching this a while back but...what I said was you can't flush a good medium and you shouldn't flush hydro more than the last day because of stress and it really doesn't matter to add nutes at that point. But yeah it doesn't help the way people talk about it.

What I do is change the res for the dark period. Not a flush. When you run your last day you run a long 48 or longer night. There is no photosynthesis happening. It is packing on its last resin run.

But you can't flush out stuff. That is nonsense.

 

[pontiacman]

Highly agree. I flush for one day. Starve them for 3 days and keep them in the dark those 3 days also. 7-10 days dry. Jar and add bovada packs. Cure minimum of 30 days...then its roll on....