How can this be?

So my Bro-in-law has grown a handful of plants outside every year for as long as I can remember…..at least 11-12 seasons. He has had a few unlucky events cost him but every yr he has a lb or two of outstanding quality buds. I never really asked him about his feeding or the other particulars of his grows…..but based on the consistent results I figured he knew his stuff.
Fast forward to more recently when I began growing indoors….despite growing a bunch outdoors many yrs ago, I was a total newbie at the indoor game. Thanks to you guys I’ve learned a ton and continue to every day.
So I recently asked him about his technique. His answer was simple: he grows in 10gal pots, uses Organic soil (he can’t remember the brand), and the only feeding he does is a bat guano tea in veg ( once every week or two) and Seabird Guano in flower……that’s it. Nothing else whatsoever.
Well I wasn’t familiar with Seabird guano but I figured it had to be lower N/higher P&K.
Then he showed me the box…..it has a bit of N, loads of P, but no K…..it was something like 2-11-0. Absolutely no potassium.
How’s that possible? I can’t attest to the fact that his buds are top shelf and not lacking in any capacity.
i was just curious about it and hoped someone a lot smarter than me could chime in and explain it.

Good soil?

Plants don’t need as much NPK as most nutrients contain. A decent organic mix will typically never need to be amended with anything containing a value higher than 5. To be honest active compost and the presence of mycorrhizae is much more important for the overall health of any plant than NPK value is. Outdoors microbes occur naturally in most soils. Fungal hyphae from mycorrhizae can run several miles if left undisturbed under ancient forest. As long as there is fungi to absorb nutrients and microbes actively decomposing organic matter the plant will extract whatever is available in the soil through cation exchange. Naturally feeding plants only pull what they need. When people say their soil is deficient that usually means it has gone sterile; there’s still nutrients left in it but without active decomposition and fungi to absorb it the nutrients remain locked out.

Bullmark said:

So my Bro-in-law has grown a handful of plants outside every year for as long as I can remember…..at least 11-12 seasons. He has had a few unlucky events cost him but every yr he has a lb or two of outstanding quality buds. I never really asked him about his feeding or the other particulars of his grows…..but based on the consistent results I figured he knew his stuff.
Fast forward to more recently when I began growing indoors….despite growing a bunch outdoors many yrs ago, I was a total newbie at the indoor game. Thanks to you guys I’ve learned a ton and continue to every day.
So I recently asked him about his technique. His answer was simple: he grows in 10gal pots, uses Organic soil (he can’t remember the brand), and the only feeding he does is a bat guano tea in veg ( once every week or two) and Seabird Guano in flower……that’s it. Nothing else whatsoever.
Well I wasn’t familiar with Seabird guano but I figured it had to be lower N/higher P&K.
Then he showed me the box…..it has a bit of N, loads of P, but no K…..it was something like 2-11-0. Absolutely no potassium.
How’s that possible? I can’t attest to the fact that his buds are top shelf and not lacking in any capacity.
i was just curious about it and hoped someone a lot smarter than me could chime in and explain it.

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Potassium hides in decomposing vegetation, gradually becoming available for absorption. Water also contains potassium salts which contribute to a lesser extent. Chances are, the plants just don't need to be fed that much potassium since it's already there.

Soil gets made for a wide variety of plants, with some bias for marketing purposes. Even though soil might be made with cannabis in mind, the manufacturer does not make it exclusively for cannabis. This means that they may offer more potassium than the cannabis genus really needs, simply because other kinds of plants do need the extra potassium. They sell more soil with a broad target.

Richard Drysift said:

Plants don’t need as much NPK as most nutrients contain. A decent organic mix will typically never need to be amended with anything containing a value higher than 5. To be honest active compost and the presence of mycorrhizae is much more important for the overall health of any plant than NPK value is. Outdoors microbes occur naturally in most soils. Fungal hyphae from mycorrhizae can run several miles if left undisturbed under ancient forest. As long as there is fungi to absorb nutrients and microbes actively decomposing organic matter the plant will extract whatever is available in the soil through cation exchange. Naturally feeding plants only pull what they need. When people say their soil is deficient that usually means it has gone sterile; there’s still nutrients left in it but without active decomposition and fungi to absorb it the nutrients remain locked out.

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what he said

Is it possible that there is some Potassium in seabird guano? I know the box says Zero, but maybe we're getting some for free?

And who is sorting the 12-12-0 bird guano from the 0-12-0 bird guano?

youraveragehorticulturist said:

And who is sorting the 12-12-0 bird guano from the 0-12-0 bird guano?

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The 0-12-0 bird guano are fed a nitrogen free feed.

twentyeight.threefive said:

The 0-12-0 bird guano are fed a nitrogen free feed.

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What?

Bullmark said:

So my Bro-in-law has grown a handful of plants outside every year for as long as I can remember…..at least 11-12 seasons. He has had a few unlucky events cost him but every yr he has a lb or two of outstanding quality buds. I never really asked him about his feeding or the other particulars of his grows…..but based on the consistent results I figured he knew his stuff.
Fast forward to more recently when I began growing indoors….despite growing a bunch outdoors many yrs ago, I was a total newbie at the indoor game. Thanks to you guys I’ve learned a ton and continue to every day.
So I recently asked him about his technique. His answer was simple: he grows in 10gal pots, uses Organic soil (he can’t remember the brand), and the only feeding he does is a bat guano tea in veg ( once every week or two) and Seabird Guano in flower……that’s it. Nothing else whatsoever.
Well I wasn’t familiar with Seabird guano but I figured it had to be lower N/higher P&K.
Then he showed me the box…..it has a bit of N, loads of P, but no K…..it was something like 2-11-0. Absolutely no potassium.
How’s that possible? I can’t attest to the fact that his buds are top shelf and not lacking in any capacity.
i was just curious about it and hoped someone a lot smarter than me could chime in and explain it.

Click to expand...

Guano has different NPK based on what they ate and the time it was harvested. Fresher guano will have more N than older guano.

My thinking is that K leaches out the easiest, then N. And P is the hardest to leach out. But that's just my understanding, so don't quote me on it. This link might help. I'd like to know more about it though if anyone has more info.

PadawanWarrior said:

What?

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It’s a joke. Like your plants.

twentyeight.threefive said:

It’s a joke. Like your plants.

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Don't quit your day job.

PadawanWarrior said:

Don't quit your day job.

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I’d tell you the same but you sleep all day.