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The myth, of the high P myth?

epicseeds

epicseeds

Member
I have been doing a lot of reading regarding the high phosphorous myth and how it is a waste to use bloom boosters with obnoxiously high amounts of P. All of this makes perfect sense but I am still confused to one thing.
For example, read this quote from Lawrence Brookes, a scientist from General Hydroponics:



"When plants are growing in a perfect happy life, when they are young and in vegetative mode, they have no particular reason to reproduce. They�re secure and growing vigorously, becoming bigger and stronger. But when the trigger comes of day-length shortening, the plants are being told by nature that the winter is coming and the end of their life is at hand. And so, at this point the plants have to completely change priorities into reproductive growth. By switching the nutrients to something that enhances flower growth and reducing nitrogen significantly � the plants are now threatened by the nutrient regimen. They are not on a starvation diet, but a modified diet that stimulates and enables reproductive growth � kind of like a goose being fed for pate. There�s a different set of priorities going on from the grower�s point of view and the crop is responding. So now the job of the nutrient is to enable the plants to produce these wonderful flowers. So we�re really now about helping that crop to flower � tremendously, because flowers are the precursors to fruit and seed. We provide the elements needed for abundant flowering and we reduce the nitrogen that was needed for early structural growth while enhancing ingredients that enable flowering."
Click to expand...


What he is saying here is it can be adventitious to "stress" a plant with reduced N and a high P is he not? This makes sense to me as well. Further, I also have been looking at tissue samples Big Mike did with different MJ strains - and results show that in fact, when in flower plants use a low amount of P...which validates the idea that high P is useless. BUT - is it true that if you reduce N and raise P it can send it into "overdrive" by stressing the plant thus forcing more vigorous flower production? This makes sense to me!



Perhaps it would be adventitious to combine the best of both worlds. Is there a general time during a plants blooming phase where it would be best to raise the P levels - and other times where P should be kept at lower levels? I agree with the theory that you should try to keep N levels similar to veg during flower as much as possible in order to keep the leaves nice and green. So perhaps at a certain point a different regimine could be switched over to a low N - high P to stress the plant. I just dont know when! Should you load up on P early during bloom - in the middle - or in the end?
 
grapeman

grapeman

Active member
Veteran
I try to make more P available starting about end of week 2 of flower. That's just me
 
E

emerald city

Been watching the phosphorus issues sinse they took my bloom ferts off the shelf.Try finding the old 10/50/10 formula's that were for sale a couple years ago.....The powers that be are Worried about P run-off into the lakes,streams and the watershed....
Ive now switched over to hydro ferts,lower in P,and have had good results...Have noticed a relationship between the ratio of N vs P[in flowering ferts] and bud density.
 
PetFlora

PetFlora

Well-known member
ICMag Donor
Veteran
Look at the NPK levels on one part grow and one part flower from any reputable mfg- FF/Botanicare/DM/AN... Grow has more N than P or K. In Flower it's the opposite. An imbalance of PK can lock out N, a possible cause of leaf claw. Also, the amount of PK an outdoor plant can use is considerably more than indoors. The amount of soil most indoor growers use is insuffucient to properly process high levels of P-K.

The big question is are the extreme PK nutes necesssary? IMHO (based on solid research), no, and Big Mike proved it. I have seen similar testing which indicates huge PK is totally unnecessary. They might actually make your smoke harsher, too.
 
E

el Dream Reader

The reason some fertilizers come with high P amounts is because when growing outdoors in soil the P is less available and has a tendency to wash out of the soil.
 
D

drewb149

Member
the fact that huge numbers of people use gh 2part or the maxibloom through a whole grow at the same ratio helps to validate the fact excess p isnt needed. i do think its a valid idea tho to try using a nute blend keeping n the same higher in pk for the first week to help stimulate the flowering process. then back to a balanced diet. then in mid to late flower reduce your n to 0 and feed strictly pk with cal mag to reboost flower production. untill your flush.
 
danks

danks

Member
those are leaf and bud tissue samples. what about the roots and stem, ive be curious to c what numbers they have and the correlation to what was fed, and a root mass test and soil test just to c what is reallybeing used up if not you just got some fancy numbers from a tiny piece of bud or leaf. the plants needs roots and stems to make the bud and leaf. give me numbers for the their total feeding regime, numbers for the soil before and after its cycle and test roots stemas leafs and bud tissue samples to get the total picture.
 
B

BorgClone

Member
was kind of unaware of all this P issue very useful information... so far i have used mostly biobizz line but only the N supplement and the root stimulator, my buds seem fine so far, next run i will try to buy the P one and see if i can notice some real change in the grow. Is it possible this is a myth to make us by more shit??
 
D

drewb149

Member
almost all the additives that the "industry" has produced are exactly that. just a bunch of worthless garbage that you dont need or could have by mixing up a few simple things yourself. AN produces nutes that work but they have specifically seperated things or left them deficient so you have to buy their supps. that goes for most manufacturers but if you look at AN they are the worst.

the lucas formula proves this imvho
 
C

csharper

Member
my first post since I got busted for my personal grow -- anyway...

"TPTB are worried about runoff" - not really - as long as they keep getting paid. However, if you have kids or care about the future of earth at all, *you* should be worried.

Although on another level, we are probably past the point of no return on east coast/mississipi/gom but that is not the best attitude.. :(

That said, high P fertilizers are for outdoors, period (if that).. P leaches from soil very easy (so just dump some more on, who cares where the last batch went says the American farmer)

However, it is important to realize the role of P in plants is more like the oil in your car than the gas. In other words, it is basically recycled and reused throughout the life of the plant.

So in a hydro/indoor system with 25-50 ppm you are all good. And even there you are dumping a shitton of P down the drain on each res change. So if you really care, you will keep trying to get that down as low as possible.

And a little anecdotal story - my last grow where I deviated from the cannabis online growing religion, I used gh maxigro at 1.4 ec, (max) the whole way through, (ebb flow,no ph control) and let me tell you, these were the healthiest, highest yielding plants I have ever had. Forget what you have been told about low N in flowering - this is almost seems like a conspiracy to keep the people down so to speak. Plants need high N at every stage, especially reproduction.

Note my low ec - when you use a bloom nute you need 1.8+, why? Because you need the same nitrogen to get the same yield. The excess P is just extra junk in your buds...

The officers who stole my just harvested stash and last flowering plant said it was the second biggest yield he had seen on single plant. Pretty good for a sunhut XL I must say.
 
F

FlaDankster

Active member
Veteran
What do we consider the cut off point..........meaning what is "into high P territory"?



I under stand 10-50-10 is high P

Or say 0-10-4

At the moment i have 6-9-0 bone meal in my soil and am using Neptunes Harvest fish at 2-4-1.

Where am i at in this "High P category"?

Lookin for input....
 
C

csharper

Member
First everyone needs to be aware the P number on the NPK labels is actually talking about the molecule P2O5 which happens to be only 44% P, the rest is oxygen. So every time you see a P number on a label, just mentally read it as half - i.e. 3-3-3 is 3-1.5-2.49 (K is actually 88% K)

FlaDankster, what you are talking about are percentages, not absolute values - you should look into PPM and the spreadsheet on CannaStats (google).

But just in terms of percentages, and considering the P conversion factor above, you are feeding 6-4 and 2-2 - if you theoretically feed equal amounts of both, then you feed 8-6, i.e. for every 4 nitrogen atoms, you feed 3 P atoms. Pretty high, In terms of percentages, 6 N for each 1 P is more than enough. On a label, that would be 6-2-K or 12-4-K.
 
T

tester

Member
Please check the date of the analysis too:
2003.
AN came out with this after 6 years, like it was something new.
 
C

Carl Carlson

fyi

http://aces.nmsu.edu/pubs/_a/a-123.html

Sampling for Plant Tissue Analysis

Guide A-123

Robert Flynn, Extension Agronomy Specialist
Shane T. Ball, Extension Agronomy Specialist
R.D. Baker, Extension Agronomist College of Agricultural, Consumer and Environmental Sciences New Mexico State University
 
A

Admiral Canna

Member
The Fox Farm feed sched, as generic as it is, is as good example here too....

They have you using no grow (N) for the first two weeks of bloom, then adding it in weeks 3-4 and then not using it again.

Every strain is different, but I have some where if I don't add a teaspoon of N per gallon in flower along with all my bloom nutes, she goes yellow quick.

Over all, I agree withholding N in bloom is the idea, but not all plants can deal with that. After all, nitrogen is one of the building blocks of life.
 
couchlockd

couchlockd

Active member
i read somewhere that the high P is to ballance the high acidity/alkalinity of K, cant remember if the K is high ph or low, but never the less i heard and read multiple places that the ammount of P in the Flowering ferts. is for PH ballance more so than anything, not the ph of the nute mix but the PH in the bottle of nutes.
 
ShroomDr

ShroomDr

CartoonHead
Veteran
couchlockd said:
i i heard and read multiple places that the ammount of P in the Flowering ferts. is for PH ballance more so than anything, not the ph of the nute mix but the PH in the bottle of nutes.
Click to expand...
This logic make ZERO sense. If it were true, how would they keep the pH stable in 'grow' bottles?
 
B

Budmentor

Member
Back in the day,before all these choices, we used a brand called Dr. Chataliers which was made for hydro. Their formula was 8-8-20. My plants loved this formula. Later I started using Rockwool Formula One (old version). It brought our pH down to 4.5 approx. so we would add potassium hydroxide to raise pH. My point is I believe high amounts of soluable potassium are much more important during bloom than phosphorus or nitrogen for that matter. My work with tropical fruit trees seems to confirm this. Just my personal opinion.
Btw: leaf analysis is industry standard to determine plant or tree health in horticulture.
 
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