How Do You Flush in Hydro?

[HairlessCaveApe]

Hairless, you are using this rise in PPM's to validate your reasoning that the plants create waste. Maybe its more like your plants are using more water than nutes? Try running the plants at 1000PPM and see if the PPM's jump so high.



How long are the strains that you guys are running? My strains run 65 days and my buds just start getting solid at the end, so I hate to stop nutes.

Hey Howdy Yamaha! Im not basing my belief about plants excretin wastes out of their roots on my ppm's rizin. I know its why my ppm's rize but Im not basin my beliefs on this. I read this somewhere long ago and I believe it to be true. As a mater of fact if you read the link to "A critical look at pre harvest flushing" and the link contained in it youl see where it confirms my beliefs. It states in the link that plants do discharge into the water threw their roots. It also loosly confirmed what I have been sayin bout the plants needin proper ph durring flush to use up the nutes stored in its veg mater. In the link it stated that the plants need certain hydrogen ions or somthing to properly transport nutes from one part of the plant to another and from what I understand ph is all about hydrogen ratios or somthin in the solution. --I run a 45 day strain and I flush for the last week. I find that the plants have plenty of nutes stored inem to take them threw to the finish. I have had the occation to go without a flush and there wasnt much of an effect on the finished product but I prefer to flush anyhow. I think alot of this has to do with the nutes your usin. Also, --yes, part of my ppm rize is due to the plants somtimes usin more water than nutes but not all of it. The majority of the ppm rize is due to the root dischargin back into the rez.

 

[HairlessCaveApe]

lucas for 7 weeks flush for 1 with florakleen no ph adjustment.

PS I want to see a MJ plant grown with 4000 ppm of nutes that is not burned and tastes sweet

albert

Check my gallery. Theres the pics but youl have to take my word bout the taste. My Herb tastes like the sweetest huneysukkls and mangoes mixt. Sukkin on a bowl of my Sugar Shack is like sukkin on a mango threw a hunnysukkle.

 

[HairlessCaveApe]

Heh heh.. Now aint that a trip. I just got off the phone with Solar Greenhouse. They make my nutes. I use theyr house brand. anyhow.. I asked the guy there if its important to keep the ph set in the water while I flush and he told me its not important. He said its good but not nesasary. So thats one for keepin your ph set while you flush as told by the man on the phone at Advanced, and one for "Its not nesasary" as told by the man at Solar Greenhouse. The guy at Solar said to do what works for you and what works good. In liue of what I read on the subject and experianced personaly, Im keepin my flush water ph ballanced. To each his own I guess.

 

[Albert Hofmann]

the point I was making is that there is no way that you are running 4000ppm of nutes (no matter what the conversion) and maintaining healthy plants. To assume that you are running 3500-4000ppm because your 2000ppm meter goes to error really fast will prove to be a highly ineffective way of measuring proper nute levels.

albert

 

[HairlessCaveApe]

the point I was making is that there is no way that you are running 4000ppm of nutes (no matter what the conversion) and maintaining healthy plants. To assume that you are running 3500-4000ppm because your 2000ppm meter goes to error really fast will prove to be a highly ineffective way of measuring proper nute levels.

albert

Your absolutly rite Abby. Thing is, thats not what I was sayin. What I said was I run my nutes at 1800 ppm's to start. Thats all nute content. By the next day my ppm's rize to over 2000. Its shurly not nutes making my ppm's higher, its waste products commin out of my roots. Now Im just judgin by how fast they rize, that within the 5 day period that I runnem, the ppm's must be round the 4000 mark. So, -Im not runnin 4000ppm's of nutes but that is how high my ppm's go before I changem out. I never add water to my rez to dilute it, all I do to maintain my rez is add ph up because my ph likes to drop like a rock. Soon as I get a trunchon that reads up to 8000 I'l know exactly how high my ppm's go. The only thing Im able to use my milwalky for is to mix, its useless to me by the next day because my ppm's rize beyond its range. Like I said, soon as I get a ppm meter that reads to 8000 Il post up pics clearly showin how high my ppm's are.

 

[Marijuanaut]

Why not post pics of your plants and lets see how they look like at harvest day !?

 

[Albert Hofmann]

Your absolutly rite Abby. Thing is, thats not what I was sayin. What I said was I run my nutes at 1800 ppm's to start. Thats all nute content. By the next day my ppm's rize to over 2000. Its shurly not nutes making my ppm's higher, its waste products commin out of my roots. Now Im just judgin by how fast they rize, that within the 5 day period that I runnem, the ppm's must be round the 4000 mark. So, -Im not runnin 4000ppm's of nutes but that is how high my ppm's go before I changem out. I never add water to my rez to dilute it, all I do to maintain my rez is add ph up because my ph likes to drop like a rock. Soon as I get a trunchon that reads up to 8000 I'l know exactly how high my ppm's go. The only thing Im able to use my milwalky for is to mix, its useless to me by the next day because my ppm's rize beyond its range. Like I said, soon as I get a ppm meter that reads to 8000 Il post up pics clearly showin how high my ppm's are.

your ppms are rising because 1800 is too high to begin with so your plants are taking more water than nutes. also, your ph is dropping like a stone because your ppm is rising. Not adding any water to your res is also definately contributing to the problem. Cut back on your nute ratios by 1/3 and top your res with fresh water and nute add back every couple days and your plants will thank you. "less is more"

albert

 

[HairlessCaveApe]

Why not post pics of your plants and lets see how they look like at harvest day !?

My galery's ful of flowers grown like I described. This has been my practice for years. The method I described works great for me.

 

[HairlessCaveApe]

your ppms are rising because 1800 is too high to begin with so your plants are taking more water than nutes. also, your ph is dropping like a stone because your ppm is rising. Not adding any water to your res is also definately contributing to the problem. Cut back on your nute ratios by 1/3 and top your res with fresh water and nute add back every couple days and your plants will thank you. "less is more"

albert

I didnt start out runnin my ppm's so high. My results wernt as good at a lower ppm. My plants would starve if I fallowed your advice. My plants eat much better when I start my ppm's at 1800. When I fed them less they showed sighns of hunger. My plants are not suffering at all, smater o fact they love theyr food just the way I mix it. Their are never any signs of overfeeding. I pay very close attetion to my plants and its taken me several years to develop theyr formula to the ratiios I use. I think the fact that I keep my root zone so perfict is the reason Im able to feed this strongly. I put brand new fresh rooted clones in that have been rooted for 2 weeks and fed veg nutes for 2 weeks into this system and even the fresh clones love it. They never suffer any nute burn whatsoever. I know it sounds incredible but its true. As I said, check my galery. If you look youl see there is no "problem" to contribute to. I never posted that I had any kinda problem. Im very happy with my feeding tekneek. I actually showed this to someone and theyr garden never grew beter. The best buds they ever had were grown using my tekneek and my formula. Im not tryin to sound cokky but I do wanna set things straight. My tekneek and my formula works great! Im gonna bump up my Sugar Shack Junk Yard thread so you can get a beter idea of what I do. I assure you, theyr as tasty as they look. Thank you very much for your advice Abby, all of it was sound, it just dont apply to me. ps- Im actually startin over now after movin to CA from Philly and the entire garden is brand new with 2wice the flower room wattage. Il be startin this new room up in a couple of days. I'l post up pics of this as well.

 

[HairlessCaveApe]

My Sugar Shack Junk Yard thread's in Growers Forum. I bumpt it up.

 

[inflorescence]

You pH the flush water to match the pH of the nute solution you were feeding it so the flush doesn't pH shock the plant.

Also, as plants take in certain ions they expell certain ions back into the water but for all the N, Ca, Mg P, K etc they take in they can ONLY expell either a H+ ion back into the water making the water more acdic OR an OH- ion back into the water making the water more basic.

Since the plant expells both of these two ions back into the water they tend to balance the pH out and only affect it drastically one way or the other it too much of one certain ion was fed to the plant.

BUT the addition of either H+ ions or OH- ions back into the water hardly increases the TDS (EC) at all because these two ions don't conduct electricity very well and thus the EC meter doesn't read them because in combination both these ions really just form together into water H20 (H+ + OH-) and pure H20 has a 0 EC.

 

[HairlessCaveApe]

Now thats science Inflorescence! Thanks! I think my ppm's get so high because of how strongly I feedem. I remember sombody describin aeroponics as simular to givin your plants a high powered nutrient enema. I know all the stuff you said to be true but I didnt know the words. I can read this stuff all day! Thanks again!

 

[Albert Hofmann]

hairless - your gallery looks good...what is the conversion number on your meter? we are misunderstanding each other somewhere. I run full strength lucas and with my Hanna (conversion 0.58) I end up around 950. This ratio is more than enough for all but maybe 2 or 3 of the strains I have used it for. If I doubled it...it would be no good for any strain of MJ out there... Either way, you have a method that is working for you...so cheers

albert

 

[sarek]

I think that an important point that everybody should mention in discussing flushing is the medium u r growing in. For example Rockwool 6 inch cubes act like sponges and so towards end of harvest can easily be 4000 ppm in resevoir of 1000 or so. That is 4000 ppm around the root zone. A 4 inch cube I am not sure but it often gets submerged during watering and slabs have yet another catrix of ppms. Coco and Hydrotons and other medias all have their way of absorbing nutrients and salts. Aeroponics has little media.

Of course drip systems top irrigate washing salts away all the time whereas flood n drain push salts up from bottom.

If u flush the 6 inch cube, slowly the 4000 ppm will aborb back into resevoir whereas a different media with little salt holding capcity will be flushed much faster.

Lastly I think that the flushings goal is to bring your media to about the same level as your res, so the 6 inch cube would be better off around 1000 or 2000.

A good goal is to keep media around your target level for res. Lower Nitrogen near end especially, this can be done by raising P and K or lowering N. If all of these exist then the need is minimized for flushing.

PHd water is important just so u do not traaumatize plant. Like with surgeons, if the have a transplant organ they store it in saline/ salty water. If it is in fresh water it would destroy organ quickly, turn it into prune. I can rarely see how traumatizing a plant can be good, whereas simulating the fall rains coming is pretty natural. But even when rains come there are still nutrients just lower than during growth season.

 

[spadedNfaded]

But everyone keeps saying they pH their flush water to 6.0-6.4. That's soil range, If i was to put flush water into a hydro bucket wouldn't it be more understandable to be in the 5.6-5.8 range?

- SubN

 

[recirculator]

Regarding the PH probe

Regarding the PH probe

Earlier in the thread someone posted that dipping your ph probe into R/O or distilled water will cause ions to leach out and render the probe ineffective.

I believe that this is true of people who keep their probes soaking in distilled (or even tap) water in between uses or for an extended period of time (as would be the case with a nutra-dip or continuous ie always in the res type meter).

Testing r/o water with a ph meter should be fine as long as in between uses the probe is stored in a proper solution containing KCl.

However, most inexpensive ph meters do have trouble making accurate measurements in water of low ionic strength (ie distilled, r/o and to a lesser extent tap water).

Do you guys tend to get repeatable quick readings in r/o using your ph meters? Even with a ROSS electrode from THERMO ORION (google it if you want) my ph meter takes forever to stabilize in low ppm water. In my experience it's more accurate to use bromothymol blue (the drops) or paper test strips than a ph meter in water with low ppms.

Happy Happy

 

[superultramega]

I'm gonna bust out some more science for you CaveApe.

Entropy.

Here's what's happening. You mix nutes and let the water get taken up by the plants without replacing it causing your ppms to rise. When you flood right before you change your res the ppms are way up because the plants have used up more water than salts. All the media is saturated with say 2300 ppm solution. When you put in the 1800 solution you get to see entropy in action. The concentration of the residual soln in your media will want to even out with the new res concentration at 1800. So your ppms rise from leftover high concentrations in the medium from the end of the last res. They continue to rise because you're not adding water to top off your rez and the cycle continues, compounding.

Why aren't you topping off your res?

 

[vprising909]

Ph'd water is standard.

For something extra special try botanicare Clearex.

It's as basic as that.

 

[_Dude]

I don't. Depriving my girls of nutrients when they're packing on the most weight would be nuts.

 

[Baddog40]

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 even suggest reduced yield and quality.

The theory of pre harvest flushing is to remove nutrients from the grow medium/root zone. A lack of nutrients creates a deficiency, forcing the plant to translocate and use up its internal nutrient compounds.

Nutrient fundamentals and uptake:

Until recently it was common thought that all nutrients are absorbed by plant roots as ions of mineral elements. However in newer studies more and more evidence emerged that additionally plant roots are capable of taking up complex organic molecules like amino acids directly thus bypassing the mineralization process.

The major nutrient uptake processes are:

1) Active transport mechanism into root hairs (the plant has to put energy in it, ATP driven) which is selective to some degree. This is one way the plant (being immobile) can adjust to the environment.

2) Passive transport (diffusion) through symplast to endodermis.

http://www.biol.sc.edu/courses/bio102/f99-3637.html

http://www.hort.wisc.edu/cran/Publications/2001 Proceedings/min_nutr.pdf

The claim only ‘chemical’ ferted plants need to be flushed should be taken with a grain of salt. Organic and synthetic ferted plants take up mineral ions alike, probably to a different degree though. Many influences play key roles in the taste and flavor of the final bud, like the nutrition balance and strength throughout the entire life cycle of the plant, the drying and curing process and other environmental conditions.

3) Active transport mechanism of organic molecules into root hairs via endocytosis.

http://acd.ucar.edu/~eholland/encyc6.html

Here is a simplified overview of nutrient functions:

Nitrogen is needed to build chlorophyll, amino acids, and proteins. Phosphorus is necessary for photosynthesis and other growth processes. Potassium is utilized to form sugar and starch and to activate enzymes. Magnesium also plays a role in activating enzymes and is part of chlorophyll. Calcium is used during cell growth and division and is part of the cell wall. Sulfur is part of amino acids and proteins.

Plants also require trace elements, which include boron, chlorine, copper, iron, manganese, sodium, zinc, molybdenum, nickel, cobalt, and silicon.

Copper, iron, and manganese are used in photosynthesis. Molybdenum, nickel, and cobalt are necessary for the movement of nitrogen in the plant. Boron is important for reproduction, while chlorine stimulates root growth and development. Sodium benefits the movement of water within the plant and zinc is neeeded for enzymes and used in auxins (organic plant hormones). Finally, silicon helps to build tough cell walls for better heat and drought tolerance.

You can get an idea from this how closely all the essential elements are involved in the many metabolic processes within the plant, often relying on each other.

Nutrient movement and mobility inside the plant:

Besides endocytosis, there are two major pathways inside the plant, the xylem and the phloem. When water and minerals are absorbed by plant roots, these substances must be transported up to the plant's stems and leaves for photosynthesis and further metabolic processes. This upward transport happens in the xylem. While the xylem is able to transport organic compounds, the phloem is much more adapted to do so.

The organic compounds thus originating in the leaves have to be moved throughout the plant, upwards and downwards, to where they are needed. This transport happens in the phloem. Compounds that are moving through the phloem are mostly:
Sugars as sugary saps, organic nitrogen compounds (amino acids and amides, ureides and legumes), hormones and proteins.

Not all nutrient compounds are moveable within the plant.

1) N, P, K, Mg and S are considered mobile: they can move up and down the plant in both xylem and phloem.
Deficiency appears on old leaves first.

2) Ca, Fe, Zn, Mo, B, Cu, Mn are considered immobile: they only move up the plant in the xylem.
Deficiency appears on new leaves first.


Storage organelles:

Salts and organic metabolites can be stored in storage organelles. The most important storage organelle is the vacuole, which can contribute up to 90% of the cell volume. The majority of compounds found in the vacuole are sugars, polysaccharides, organic acids and proteins though.


Translocation:

Now that the basics are explained, we can take a look at the translocation process. It should be already clear that only mobile elements can be translocated through the phloem. Immobile elements cant be translocated and are not more available to the plant for further metabolic processes and new plant growth.

Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival. Translocation is transportation of assimilates through the phloem from source (a net exporter of assimilate) to sink (a net importer of assimilate). Sources are mostly mature fan leaves and sinks are mostly apical meristems, lateral meristem, fruit, seed and developing leaves etc.

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.

For example nitrogen: usually plants use nitrogen to form plant proteins. Enzyme systems rapidly reduce nitrate-N (NO3-) to compounds that are used to build amino-nitrogen which is the basis for amino acids. Amino acids are building blocks for proteins, most of them are plant enzymes responsible for all the chemical changes important for plant growth.

Sulfur and calcium among others have major roles in production and activating of proteins, thereby decreasing nitrate within the plant. Excess nitrate within the plant may result from unbalanced nutrition rather than an excess of nitrogen.

Summary:

Preharvest flushing puts the plant(s) under serious stress. The plant has to deal with nutrient deficiencies in a very important part of its cycle. Strong changes in the amount of dissolved substances in the root-zone stress the roots, possibly to the point of direct physical damage to them. Many immobile elements are no more available for further metabolic processes. We are loosing the fan leaves and damage will show likely on new growth as well.

The grower should react in an educated way to the plant needs. Excessive, deficient or unbalanced levels should be avoided regardless the nutrient source. Nutrient levels should be gradually adjusted to the lesser needs in later flowering. Stress factors should be limited as far as possible. If that is accomplished throughout the entire life cycle, there shouldn’t be any excessive nutrient compounds in the plants tissue. It doesn’t sound likely to the author that you can correct growing errors (significant lower mobile nutrient compound levels) with preharvest flushing.

Drying and curing (when done right) on the other hand have proved (In many studies) to have a major impact on taste and flavour, by breaking down chlorophylls and converting starches into sugars. Most attributes blamed on unflushed buds may be the result of unbalanced nutrition and/or overfert and unproper drying/curing.