The Myth of Low N

[desertsquirrel]

I already posted this at ********* so i apologize if its a repost for you, but i really wanted shroomdr to take a look at this work....

I remember first reading about the myth of high P in the late 90's and early 2000's. Ever since then i have been working on nutrient profiles; finding that indeed lower P with occasional boosts seemed to do far better. However i had this constant feeling that something else was off. Time and time again i found myself overly concerned with both N and cal/mag issues.

Recently i found myself more concerned then ever with my profiles as im taking over several rooms of Under Currents. In doing that work i calculated the numbers from both agriculture industry tissue samples as well as cannabis samples and was blown away by what i may have found. (i cant believe i never ran the numbers on these samples, i have had the doc for years). Anyway before i get too much into my conclusions, here is the work.... I should add the profiles are halved for undercurrents, and the spreads are in ppm and then ratios.

 

[desertsquirrel]

Initial observations.....

The myth of low N. N almost doubles from Veg to flower according to the plant tissue samples. And while nearly all hydroponic nutrient lines provide (or seem to strive to provide) 100% of the ppm need for each mineral, N is provided at 60% its actual PPM need. Possibly look to Urea or multiple nitrates to fix this problem.

Higher calcium is needed for plant tissue production until stretch is complete.

cal levels half durring flower and mg doubles. Following stretch switch from cal-mag to to Epsom salts.

Keep S = with Mg

Low P with spikes 3 times beginning with stretch. (50/30 is in perfect ratio with the tissue analysis).

4% of the tissue in agri industry was supplemental minerals, w/about 8% for mmj. This cultivar uptakes twice as much as most.

 

[tester]

How did you get those numbers below the nute profiles?

 

[YosemiteSam]

Are you actually running more N than K in flower?

If you are you might wanna get some tissue analysis of your own plants. Just guessing but I bet it would show a lot of incomplete proteins, i.e. amino acids. Be careful...the borg feed on aminos.

 

[desertsquirrel]

no sam, im not running more N than K yet. But i am going to test very soon, and of course have the tissue analyzed...

Im not too worried about the borg, our integrated pest mgmt system is solid.

 

[tester]

Anyway, have a look at this post.

 

[Marquis de Sod]

Low P with spikes 3 times beginning with stretch. (50/30 is in perfect ratio with the tissue analysis).

this isnt making any sense to me. little help?

 

[desertsquirrel]

search for rezz dogs recipe, i think its a shroomdr thread. that should clear things up marquis.

 

[geopolitical]

I've been doing this for years.

 

[desertsquirrel]

sorry tester i didnt realize who you were. thanks for pointing me to the other thread i cant wait to give it a closer look... which numbers were you asking about? i did my best to read the ppm off the graph, but obviously id like more accurate numbers.

 

[IwannatokeNbone]

ive heard on this thread somewere that a grower got his most potent sticky buds with standard peters 20-20-20. the whole nute game to be honest doesnt appeal to me, almost any nute will work, almost being the word

 

[grapeman]

What do you mean by

Keep S = with Mg ??

Also, looking to urea to provide N in flower would be a mistake. It takes at least 30 days in ideal conditions for the majority of urea to become a usable form of N for the plant.

 

[YosemiteSam]

Hey tester...have you reached a conclusion on what kind of profile you think would be best for marijuana?

 

[desertsquirrel]

Grape man, S and Mg levels on the tissue samples are equal, thats what that means..

Also im confused myself about urea/ammonicals for the same reason you say, the long period of nitrification. However i think that that refers only to soil as once the conversions have started (as soon as NO3 becomes NO2) its unusable. It seems that urea must be a usable form of N seeing as it is a main source of it in Advanced products, presumably the nutrients used in the tissue samples. This is also probably the reason your finding good results with Pure Flowers, as phosphites are actually poisonous to plants but easily converted to phosphates in the rhizosphere.

 

[desertsquirrel]

What i am so interested in is this...

The numbers taken from plant tissue already show extreem levels of N. My question is how did this come about? Advanced Nutrients profile offers maybe 60% of the N found in the tissue that that profile was feeding. What does this mean? Was the solution simply being depleted of N faster? Does that mean 40% more solution was needed to be transpired to achive the 100% of N found in the plant? How much harder is the plant working to achive this? Does that also mean its over-uptaking 40% of the rest of the solution?

If N is already present in the plant tissue, the plants getting it. Why would altering the feeding to reflect what the plant is actually taking up result in more leaf and less bud? we are assuming big mike had good herb tested right? I will have alot more insight on this matter when i begin doing my own tissue samples this summer. I think leaf/stem/bud samples need to be done, among other things....

 

[Momerath]

Way cool thread, thanks for the great info. Its interesting to see that a lot of nutrient companies are producing products that are believed to be optimal, yet according to these charts some can really be lacking (or overdoing it) in some departments.
Seems like a little experimentation is in order for this year.

 

[ShroomDr]

First, i am no expert desertsquirrell, i just complied a bunch of info, and organized it so it would be easier to compare. (I still think im an idiot for using the measurement mL/Gal, but thats what i use.)


As for the thread subject,

Anyone who has cut the N too early in flower is well aware of the need for N though mid flower. Plants that are 'school bus yellow' @ day 30 are not going to yield good flowers. Thats no myth!

You have to realize most people dont care about this shit. They dont care why it works, they only care that it works. So whether gardeners realize how much N they are feeding is irrelevant to them.

IMO, i think most Cal-Mag users forget the fact that there is a lot of N in the bottle. This would fit with the thread subject. (Note: Adding nitrate late in flower makes for shitty tasting flowers).

I just dont see it as a myth. The P paradox is mfg thinking we want more P, so they provide, even though its not necessary.

 

[desertsquirrel]

Thanks for dropping in Shroomdr. When your the only one doing something your the expert by defult =). I totaly agree that most people dont care, but more and more are starting too; and i think your work is a significant part of the reason why...

So, what do you think is going on with the disparity between the ratio of N going into the solution and then ratio of it in the actual plant tissue?

 

[tester]

Hey tester...have you reached a conclusion on what kind of profile you think would be best for marijuana?

Hey Yo,

Nope, my only conclusion is that there isn't enough reliable data out there to draw a conclusion.

GH Pharma might have some answers, AN probably made some more "research" but none of these are available.

 

[ShroomDr]

So, what do you think is going on with the disparity between the ratio of N going into the solution and then ratio of it in the actual plant tissue?

My 100% speculation would be that it is similar to the fact that just because the plants can take a high EC doesnt mean they need it, or that it is beneficial to run it so high.

The plants use what they need, but im no scientist.

I also think its worth noting (although im not sure it was this thread) that someone said that plants 'need more Si' than provided. 'Need' is inaccurate IMHO, Si can substitute for C in the plant tissues (they are both in the 'carbon group' on the periodic table). So, just because it was used in the plant tissue, doesnt mean it was essential (aka NEED). On the other hand, i do supplement with Si.

So.. to the best of my limited understanding... plants use what they need, or what they can (although you can definitely overfeed them).


Lets not forget that the info on that "Berlin' cut is over 8 years old, and from the prestigious and impeccable AN.