Yields on 15 lights were within a pound of each other between the 40ppm grow and the one that went up to 90. Genetics were not exactly the same so no way is a pound significant.
Quality did improve though.
So the plants compared for quality and trichome production were not clones?
Were they seeds?
Different strains?
I will say this for SS. If you have ever grown Larry OG x anything you will know those are excellent looking buds. That stuff just flat does not grow what anyone would call trophy colas. So I am giving you a big ol well done SS. There is no question that Spurr formula is a good one...the only question is if it is the best one or not.
What I found...I think...is that P just flat does not influence yield much at all. My plan is to stick to 40 ppm through stretch. But here is where I disagree SS. I think bumping it after stretch, at least for a couple of weeks, increased trichome production quite a bit.
That is based on actually trying it, not on a study.
I also found that while a K:Ca:Mg ratio of 4:2:1 works pretty damn good it does end up showing some Ca and/or Mg deficiencies late in the cycle. This time around I am going to hold most other things equal but go to a 3:2:1 ratio for those things. We will see what we see.
The plant I have been posting, the ISS, is harvested. It is not dry yet but it is gonna be somewhere between 2 and 3 pounds. It is a 15 light, 15 plant setup...so should be at least 1 gram per watt or more.
But...it is an ISS, not an OG...so comparison really don't mean shit.
Anyways...next go around my peak will be...125-90-250-166-83-98...N-P-K-Ca-Mg-SiO2.
My thinking is that the healthier you keep the plant all of the way to the end the more you let it express its genetic potential. I failed that this time with the Ca/Mg problem. Live and learn.
I was plugging different companys ferts in the cannastat calculator. f'in Advanced Sensi Bloom A/B 10ml gallon is
152N 66P 252K 106Ca 21Mg
my friend was on a budget last ran just there a/b and some sweet and said he add a much better run then when he used all there additives
https://www.crops.org/publications/aj/abstracts/69/5/AJ0690050832
Responses of Greenhouse-grown Cannabis sativa L. to Nitrogen, Phosphorus, and Potassium1
- C. B. Coffman and
- W. A. Gentner
Abstract
Growers of illegal Cannabis sativa L. use various cultural practices to maximize crop production. The objective of this study was to evaluate the morphological and biochemical responses of greenhouse grown C. sativa to soil incorporated N, P, and K as they reflect the geographical origin of Cannabis derivatives. Fertilizers were blended with Ap horizon soil from a Gilpin silt loam before placement in 12-cm pots. NH4NO3-N was applied at 0, 25, and 125 ppm. Phosphorus and K from super-phosphate and KCI, respectively, were applied at 0, 50, and 150 ppm. Forty-five-day-old anthesic Cannabis plants were harvested and combined leaf and flower tissues were analyzed for cannabidiol (CBD) and Δg-tetrahydrocanna-binol (Δ9THC). Nine essential elements were also measured in plant tissue. Plant growth, tissue yield, and concentration of CBD and Δ9THC were positively correlated with extractable P2O5 (p < 0.01). Phosphorus concentrations in tissue were similarly related to yield of dry matter and cannabinoid concentrations. Uptake of K was positively correlated with extractable K.2O across all treatment levels (r=0.40**), but was negatively correlated with tissue yield (r=--0.36"*). Growth and tissue yields were negatively related to total plant N (p< 0.01). Levels of extractable P2O5, Mn, B, and Mg were associated with specific concentration ranges for several plant elements plus Δ9THC. Thus, it was possible to partially characterize a soil by tissue analysis. For example, all of the plants grown on soil with less than 100 ppm of extractable P2O5 contained less than 8,000 ppm Δ9THC. Usefulness of such relationships will be dependent upon extensive evaluation of Cannabis on different soils under various cultural conditions. At this time, the reliability required for determination of origin of Canabis derivatives via chemical analysis does not exist when only essential elements and cannabinoids are considered.
That study is far from conclusive, and it's pretty darn flawed too. I pointed out a few issues with methodology of that study in another thread here and here (elsewhere too). That said, that study is better than nothing and does provide some evidence that 'high' P levels may increase THCA (and CBDA) ... but no mention is made of trichomes.... The biochemical mechanisms responsible for synthesis of cannabinoids are not clearly understood; therefore, we cannot yet explain how previously discussed elements affect cannabinoid production. Phosphorus may be involved in cannabinoid biosynthesis via the interaction of geraniol phosphate and olivetol (Mechoulam, 1973). The other elements may affect related enzymatic reactions ...
YS said:They were all clones. It was not the exact same line up both grows but there was considerable overlap. In that room we run nothing but clones of proven cuts. We have a small room for seed runs, selection, etc.
Plants grown at 90 ppm P in both grows...clones from the same stock plants...were noticeably more triched out.
From a purely statistical point of view maybe I cannot say with high confidence anything about the yield...but based on my experience with all of the plants involved I do not think there is any difference in yield.
edit...nice looking plants analog. They should be so tasty.
That answers that question. P is important in trich production and there has been anecdotal evidence of this for many years and it has been demonstrated time and again by very good and very experienced growers so I expect you have just demonstrated the same thing. The fact is YS, you also had a Ca deficiency in your latest grow and perhaps Mg as you say. It would have been interesting to see what the yield outcomes would have been without this deficiency.
Spurr,
What spread sheet is that that you used for your calculations? Is it your own creation or can it be found on the web somewhere. Thanks
O
One question Spurr (perhaps I missed it) what media are you growing in?
YosemiteSam said:I will say this for SS. If you have ever grown Larry OG x anything you will know those are excellent looking buds. That stuff just flat does not grow what anyone would call trophy colas. So I am giving you a big ol well done SS. There is no question that Spurr formula is a good one...the only question is if it is the best one or not.
YosemiteSam said:What I found...I think...is that P just flat does not influence yield much at all. My plan is to stick to 40 ppm through stretch. But here is where I disagree SS. I think bumping it after stretch, at least for a couple of weeks, increased trichome production quite a bit.
YosemiteSam said:That is based on actually trying it, not on a study.
YosemiteSam said:I also found that while a K:Ca:Mg ratio of 4:2:1 works pretty damn good it does end up showing some Ca and/or Mg deficiencies late in the cycle. This time around I am going to hold most other things equal but go to a 3:2:1 ratio for those things. We will see what we see.
YosemiteSam said:My thinking is that the healthier you keep the plant all of the way to the end the more you let it express its genetic potential. I failed that this time with the Ca/Mg problem. Live and learn.
How much sulfer would be too much? using cns-17, sweet, and big bud. You could get really close to those numbers but the sulfer is at 125
Spurr we hardly agree on anything but I still enjoy your input. It's a very valuable part of the metanarrative happening here.
Re Si, there are some that are now saying it should be listed as an essential mineral element. Others also say that Ni should be listed as an essential mineral element.
As for debating on P that's why we're here and I am completely open to findings. Dogma is the mother of all ignorance. Let's see where this all goes is my only thoughts - however there seems to be benefits exhibited by cannabis where higher P is present.