To tell the whole story would need assays from leaf, flowers at a couple stages, stem and root mass. And adjust for the percentage of each being fed for that particular stage. Seems like currently we typically define 4 stages. Seedling, veg, early flower, late flower
1 Like
Hey @lefthandseeds
Please tell me what is the smallest amount of solution you make? I am asking because I need really small amounts of micronutrients. And realy precise weight.
Can I make diluted liquide solution and store it?
My English is good for reading, but I sweat composing longer texts…
So please take a look, if you haven’t already, some research.
Excessive use of phosphorus has already been discussed here, but according to these studies, potassium should also be cut, especially during flowering. And in addition, they recommend high doses of nitrogen throughout the entire grow
There are many links to other research in this first paper. It would be too many to post here, but here are two related to potassium
4 Likes
3 Likes
It sounds like some of the material in these is similar to some that was quoted by @lefthandseeds in other posts, but I could be wrong. I read but mostly skimmed some of the studies. I’m interested in the ‘K’ related stuff. It sounds like they’re saying that ‘K’ in the range of 60-175 ppm is “optimal”, in their tests. But as always, this just leaves me with more questions.
4 Likes
The smallest that I mix is usually 5 gallons (approx 19L). For that amount, I would typically use 1g of chelated micros. If you can get a small 0.01g scale, it is good enough.
If you have to mix everything separately, weighing the sodium molybdate would be pretty challenging. So I’d recommend a mixture like plant prod.
Those are some interesting papers. I’m very interested in the 2nd one. I think Jacks typically runs about 230ppm in the “321” formula. It’s a little surprising to me that they would consider that too much. Currently, I would not consider running less than 200ppm in flower — but I have to see what their Ca numbers are before I make any conclusions.
For N, I know they are optimizing yield but I would not recommend using their numbers. In veg, it would be fine, but I’ve seen a lot of plants showing nitrogen excess at rates far less. The more sativa leaning, usually the more sensitive to N.
Secondly, there is a tradeoff between yield and cannabinoid concentration. You might have more flower under high N, but it will have lower resin concentration. This has been published previously, and I think I’ve linked it somewhere in this thread. Basically you grow bigger flowers, but the resin spreads out over the larger surface. I prefer to reduce nitrogen after veg or stretch.
Their P numbers of 59ppm is pretty good, but also strain dependent. If you have a strain that you know to grow big root masses, then you might have better results with higher P during veg and especially through stretch. After that, it can be reduced.
All of these studies have somewhat limited value though. It’s good to be aware that there is no single formula that works across all strains. They are usually testing heavy feeding polyhybrid commercial strains, which are by far the easiest to grow. If you take 190ppm+ N into a landrace sativa grow, you will quickly learn to take these studies with a grain of salt and your plants might be as far from optimal as possible (dead).
There’s a very wide range of optimal nutrient solutions, and if you like to grow a lot of different strains, you might find it takes a few grows to figure out.
7 Likes
I’ve read some of the second paper:
The plants were then divided into five increasing treatments of K supply; 15, 60, 100, 175, and 240 ppm, and grown for 30 days under 18/6 h light/dark photoperiod using Metal Halide bulbs (400 μmolm−2s−1, Solis Tek Inc, Carson, California) in a controlled environment growing room.
It makes sense, they aren’t flowering their plants. You don’t need a lot of K in veg. 1:1 with calcium is fine.
This is a statement to remember in the intro:
overall trends of accumulation were similar for the two genotypes demonstrating competition for uptake between K and Ca and Mg, and no effect on N and P uptake except in the K-deficiency range. The extent of accumulation was higher in the leaves > roots > stem for N, and roots > leaves > stem for P.
This is why plants with larger root systems like more P.
Two hundred and forty ppm K proved excessive and damaging to development of the genotype Royal Medic, while in Desert Queen it stimulated rather than restricted shoot and root development. The differences between the genotypes in the response to K nutrition were accompanied by some variability in uptake, transport, and accumulation of nutrients. For example, higher levels of K transport from root to the shoot were apparent in Desert Queen.
And this is a good statement, because it should be an indicator that optimal nutrition is varied by genotype.
8 Likes
yeah and from strain to strain the difference can be so big! so i think the numbers in the studies can help to pin down a few things. but by the end of the day it always comes down to testing out what you strain likes.
5 Likes
I haven’t found the paper for this, but here’s a screenshot from an interview with Nirit Bernstein, where she recaps their research.
On the same graph, the first group of lines is veg and the second is flowering.
Calcium intake and deposition is interesting. These two cultivars stop calcium intake around day 30 of 12/12.
2 Likes
That’s actually quite interesting. I would think it’s probably tied to the length of the photoperiod. 30 days would probably be about right after stretch in a lot of strains.
Do they also have plots for other parts of the plant, like leaves and flowers/inflorescence?
2 Likes
For now there is none. She mentioned that this publication will be published soon. And the video was created six months ago.
But they analyzed all parts of the plant on a weekly basis on 3-5 cultivars
Here is the video if anyone is interested. She talks about this at 41:00
https://youtu.be/lfjL4YWJhH8
5 Likes
Hey @lefthandseeds
Please give me some advice.
This is what I have:
Monopotassium phosphate
Potassium nitrate
Potassium sulfate
Calcium nitrate
Magnesium nitrate
Magnesium sulfate
Potassium silicate
Fulvic acid
Micro mix
Fe dtpa
Boric acid
If I am going to use all of these, what would be the order of adding the ingredients?
Also use
Ro water
Phdown phosphoric acid
Ph up potassium hydroxide
Thank you
2 Likes
Scienceinhydroponics (Daniel Fernandez’s website, and youtube channel) has some blog posts and videos on diy fertilizers. Though I don’t think they specifically say “these things have to go in this order”. I’m sure lefthand will reply, just wanted to mention this, in the mean time.
1 Like
That is interesting. I tried dropping calcium on a couple plants at 8 or 9 weeks and literally overnight all the leaves were fried from calcium deficiency… Just didn’t have the right plants I guess 
6 Likes
I would do potassium silicate first.
Then you can add everything else together except the calcium nitrate
then calcium nitrate.
Although I’m not sure if fulvic acid would be able to stay in a res for days without making it nasty.
Unless you have really bad tap water or well water RO water is not really necessary either. Unless you already have a system installed at home or something.
3 Likes
I agree with @neogitus. But I’d also mix the magnesium nitrate at the same time as the calcium nitrate. You could do potassium nitrate at either time.
Generally speaking, you keep the sulfates and phosphates together, and the nitrates together. But potassium nitrate is mostly ok in either.
I’m usually do potassium silicate first, and then correct the pH. But I’ve stopped using silica products because they’re a pain and I’m a little scared of them. Silicosis is what killed thousands of miners back in the day… maybe an unwarranted fear, but it’s the only one I always handle with a respirator.
8 Likes
“The results also suggest that different cannabis varieties may experience discrete transcriptional regulation of cannabinoid biosynthetic genes”
From the intro to this study about methyl jasmonate:
6 Likes
Impello Bioscience has a liquid product called Dune that provides silicon. Monosilicic acid. No dust. We’ve used it for the past couple of seasons. No troubles, running low dosage. PHing of the nutrient solution hasn’t been an issue.
Although, the media we are using this with is a peat based mixture. I haven’t been monitoring the runoff for PH drift simply because the plants haven’t exhibited any problems.
8 Likes
Wouldn’t you add the calcium nitrate before everything else? (But still after the silica)
Any time I’ve tried adding calnit or gypsum(calsulf) after already mixing maxibloom for instance, it precipitates. If I do the calnit/gypsum before the maxibloom and wait for the water to clear before adding maxibloom, then it doesn’t precipitate at all 
8 Likes
Have never had that issue with calcium nitrate. I haven’t used gypsum in any reservoirs before but the solubility of it can increase at higher pH levels. If you are using tap water that is usually at a pretty high pH out of the tap and then after adding nutrients depending on the alkalinity it can bring the pH down pretty significantly. I think gypsum has pretty low solubility also. Not positive though.
8 Likes
Doesn’t maxibloom have a pretty high phosphorus amount? I think it must be causing some calcium phosphate.
8 Likes