Theories on proper NPK cannabis ratios

Basic Growing Info
#1

Lately, I’ve been researching my regular garden plants and flowers for proper nutrient ratios and finding common ratios between different plants in the same planter for my spring fertilizers. For example, My roses like any of the following ratios 1:2:1, 1:2:2 and 2:3:1 and the bulbs had their own ideal ratios, but the common ground for that planter was 1:2:1

So far, every one I talk to and every thing I read has a different theory on the perfect NPK ratios for Cannabis. Please share your theory or any scientific information you grow by… All ears over here.

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Mixing your own custom nutes?
#2

My theory is to make sure all the bases are covered N = legumes or cover crop P= rock dust, bonemeal etc, k= a potash source… but it takes more than just NPK ,it’s good to have a multi minerals (trace)source Kelp provides up to like 80 elements or minerals but in the end it’s all about microbes if your in soil, all plants will send specific exudates through the roots into the rhizosphere and specific bacteria will make those nutrients available when they break them down no need to guess what your plant wants as far as fertilizer go IMO plants have been able to survive long before the discovery of fertilizers they have be able to do it for thousands of years!

So long story short! I don’t believe there’s such a thing of a proper ratio of NPK for cannabis or any other plant for that matter!

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#3

Always love your organic approach @Tinytuttle! Appreciate your input. btw where does one get the rock dust you often mention?

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#4

Up to this point in my growing of cannabis I haven’t used a lot but I use azomite in my mixes but will this coming year, some that come to mind are Greensand , rock phosphate, dolomite lime, basalt would be some good ones !

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#5

I would bet there’s someone on the site running a modified Lucas formula, with a tight grip on this subject.
@Kraven any chance you can point us in the right direction?

(Let me see what I can’t dig up in the mean time. I should really know this off the top of my head by now.)

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#6

I heard @DavesNotHere I believe talking about that in another thread I’m intrigued of what that’s all about!

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#7

I was using the Lucas formula in soil with GH hard water nutrients and it was pretty good, but I eventually switched to organics and would only switch back if I tried hydro or coco.

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#9

I’m with @Tinytuttle. I don’t believe there is a perfect ratio for cannabis. Each cultivar seems to like its own thing. The best bet is like turtle said cover all yoir bases by going beyond just NPK and making sure there’s ample amounts of micro and trace minerals in it as well.

My main goal with my cover is adding diversity of biology and to help in water retention and balance. Most beneficial microbes you want in your soil need a live root to either live on or in, it doesn’t just have to be cannabis. Also, not only does the top 1/4" of soil stay moist and booming with life but the live root help keep water evenly distributed through the soil.

N and K actually become less important if the grower is using high quality composts. N because in a health living soil with compost you get all those nice nitrogen fixing bacteria for free that you’d have to pay for with products like Azos. K because through soil testing people with more time and knowledge have found that almost all compost have an overabundance of potassium.

I use two different rock dust in my soil mix and topdressing. Glacial rock dust and paramagnetic rock dust.

I use glacial over azomite because of the high heavy metals present in azomite than the glacial rock dust.

The paramagnetic rock dust is a form of volcanic basalt, but it has a high natural magnetism that causes it to align in the soil north/south and aids in the transfer of ions in the soil. I know it sounds crazy but there’s is actually some.pretty cool science behind it.

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#10

Where do you buy this dust?

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#11

Here’s some paramagnetic rock info to wet your beak.

Here’s where I normally order mine.

Here’s where I normally get the glacial rock dust.

I mix them 50/50 then use it at 4tbsp/gal of soil.

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#12

I’m as stoked on the websites as I am the info! Thanks!

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#13

Where I live in the Cascades its all glacier silt deposits and rocks. I never knew that I had valuable growing soil. I also have lapidary rock dust from polishing rocks. Does that work to? I have been throwing it away.

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#14

The lapidary dust may be a valuable addition to the soil depending on what stones you’re cutting. :joy::joy:

Puns aside adding it will add minerals of some kind depending of rock type. You’d have to see the composition data to see what all it could possibly add. The thing I didn’t mention is most of those mineral won’t be broken down and become plant avaible without a thriving microbe and fungal population to break them down using natural acids and bases per what the plants communicate to them what they want.

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#15

There is absolutely a correct nutrient ratio for Cannabis. And there is an acceptable range for each nutrient that’s not optimal, yet doesn’t show much, if any, deficiency or toxicity symptoms.

Taking it a step further, in soil the vast majority of the nutrients are not immediately available to the plants and you can have a deficiency of an element that is abundant. That’s why Mammoth P can command the price it does – Phosphorus is notoriously unavailable and they’ve got the magic key to unlock it.
On the other hand, Nitrogen is hyper available and will be assimilated whether it is needed or not, at the expense of a large portion of the plants energy.
And then when Potassium is low, Sodium can take its place to an extent.
(I believe there’s a similar situation when calcium is low, the walls of the cells are lined with a replacement element that leads to easier attack by bugs and fungi, but dont quote me on that one)
Silica is another element that will show no symptoms if a plant is deficient, but there is an optimal range where you’ll have a stronger plant from its presence.

It’s a game you’ve gotta play based on the inputs and how long they take to break down.

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#16

Putting organics aside, there has to be a perfect ratio for it. I can look up every other plant and some scientist has found and published usually 3 different npk ratios that are optimal for a specific type of plant. It doesn’t mean that those plants don’t need other special amendments or nutrients like magnesium but they all have optimal ratios for the npk. Cannabis is just an annual plant, not a mutant. There has to be a magic formula.

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#17

Also @Worcestershire_Farms have you used Mammoth P? I decided a few weeks ago to buy some despite the hefty price tag and test it on my next grow. Any observations or advice there?

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#18

The fact that cannabis research has been restricted for so long is probably the reason you can’t find a peer reviewed research article that gives you a straight answer. Even if you found one, one article doesn’t say much since results should be reproduced multiple times before any conclusion can be made.

Why does science have to be so complicated?
Oh yeah, because it’s science LOL.

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#19

Nah, It’s out of my price range. :joy: :sob:
Theoretically tho, it only needs to be bought once and it can be multiplied ad infinitum.

@Meesh I’m still working on finding a good thread on raw salts to pluck a ppm breakdown from. The one I have been looking for was probably on hempcultivation_dot_com which became gardenscure, which apparently evaporated.
I have a short day at work tomorrow so I’ll put in some time and should have something worthwhile tomorrow night.

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Oni's 2nd grow. Lessons learned
#20

Meaning I can put it in compost as like a charger or starter?

That’s awesome of you! I’m sure everyone is curious!

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#21

Preliminary update: Comparing a bunch of recipes designed for hydroponic cannabis grows, theres a general trend toward
N100-200
P50-150
K150-300
Mg50-75
Ca100-150
S50-150
Si50-150
Fe10

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