The myth of 10:10:10 fertilizer.

[fredman]

Maybe not that applicable to bonsai....but still worth knowing I think.
Yeah we flush regularly, but seems to me it don't give the trees what they really need.
I first heard of the 3:1:2 ratio that plants takes up nutrients, some 10 years ago....and still choose my fertilizer as close to that I can.

 

[fredman]

A good example of a 3:1:2 ratio fertilizer I used to love, was Dyna gro Foliage pro 9:3:6.....but I can't find that anymore.

 

[Shibui]

Need to remember that we measure fertiliser ratios differently in Australia and, I think, in NZ and some other countries. USA measures the percentage of the compound eg K in fertilisers usually comes from K2O and P is often P2O5. The O in those compounds weighs something but is not used by the plants. Down here the fertiliser ratios measure only the elemental part of the P and K so a fertiliser with the same ratio numbers here actually has more P and K than one with that ratio sold in the USA.
There's not a huge difference but maybe worth knowing?

 

[pandacular]

I can’t remember who, but I know a few well respected members of the site have emphasized that plant growth is dominated by the most deficient of these three nutrients, and even provided some ag school studies on the topic. Thats a concept that certainly makes sense to me.

I have always been skeptical of the perfectly balanced idea, for a number of reasons, but have no first hand experience with it one way or another.

 

[Glaucus]

I've seen some of this guy's videos. And all claims I have seen him make are spot on scientifically accurate with what my basic biochemistry understanding is. Or what I have read in the literature. This is genuine. Not broscience.

 

[leatherback]

I can’t remember who, but I know a few well respected members of the site have emphasized that plant growth is dominated by the most deficient of these three nutrients, and even provided some ag school studies on the topic. Thats a concept that certainly makes sense to me.

I would be one of those. Optimizing input, and having different requirements of different elements is a common understanding in ecological science & animal nutrition, which I happened to have spent quite a bit of time on.

This where the concept of limiting factors comes from. In principle, typically there is one element that will first hold back development of an individual. Where element could be nutritional, but also water, sunlight, rootmass, temperature are elements in this sense. An living individual needs to ensure all components are sufficiently provided for optimal development, yet not so much thet they become poisonous. For animals this affects how they use space to optimize diets, and probably explains migration of animals in savanna systems. And there is no fundamental difference in the needs of plants, except that they cannot choose where they move to so there is a much clearer local-conditinos effect for plants than animals.




For those who wish to spent a day of their life wasted on reading more dry stuff: Intro & Graphs from the introduction & sythesis of Charting the Quality of Forage, Ferwerda, 2005

 

[Glaucus]

Liebig's barrel is put in like every presentation on plant growth:

Liebig's law of the minimum - Wikipedia

en.wikipedia.org

plant growth limiting factor - Google Search

When adding fertilizer, you just want to make sure one of your nutrients isn't your bottleneck. That's why often adding 10-10-10 doesn't make sense.
Plants likely remove fertilizer in a 3:1:2 ratio. Additionally, phosphorous is least likely to completely wash out from your substrate. Though I haven't seen any specific bonsai data on that. Could be interesting.

I know very little about plant ecology, but my understanding is that plant species can change extremely abruptly when the geology changes. Like with almost no transition. Because of how plants are able to take up minerals as they are specialized for one type of geology, and not the other. Even when in culture the difference in species and their preference isn't that big, natural selection will amplify this change.
The botany guy with the strong Chicago accent on Youtube often explains this. The 'crime pays, botany doesn't' guy.

Need to remember that we measure fertiliser ratios differently in Australia and, I think, in NZ and some other countries. USA measures the percentage of the compound eg K in fertilisers usually comes from K2O and P is often P2O5. The O in those compounds weighs something but is not used by the plants. Down here the fertiliser ratios measure only the elemental part of the P and K so a fertiliser with the same ratio numbers here actually has more P and K than one with that ratio sold in the USA.
There's not a huge difference but maybe worth knowing?

Not quite. NPK ratios are always expressed as if P comes from P2O5 and K comes from K2O. Even thought P2O5 and K2O don't exist as actual chemicals. I believe this is basically universal across the entire world and this way of expressing is enforced by regulatory bodies. Of course elemental phosphorus exists. And the phosphate ion exists. But not P2O5, whatever that would be. Phosphorus pentoxide does exist, though. But that is P4O10. P2O5 is used as a proxy. It doesn't exist. Usually, a fertilizer would contain mono potassium phosphate. And then a bunch of animal waste products high in nitrogen, like blood meal, feather meal. And then ammonium nitrate or potassium nitrate are added to get the desired NPK ratio.

Any resource on fertilizer will have a table for converting say P2O5 to actual phosphate ion concentrations. If you are like a normal person, you want to know the molar concentration of phosphate PO4 3-.

 

[Glaucus]

Correction, of course K2O does exist as a chemical. But it isn't put into fertilizer products. Even though they all list an equivalent amount of K2O on the label. P2O5 is the actually completely fictional one.
Also, many fertilizers do get their potassium from different forms of potash. Which contains potassium sulfate, potassium nitrate, potassium carbonate, potassium chloride, etc.
This is mined and cheaper but does not contain phosphate. mono potassium phosphate is purely a fertilizer industry chemical for high quality low EC fertilizers.
Manure is high in organic phosphates. so probably cheap fertilizers get their phosphates from manure. Not from mono potassium phosphate either.
Sadly, labels don't always list what the actual chemical composition of the fertilizer is. Just the NPK ratio, which part of N is organic and inorganic, and then some general ingredients.

Ah Shibui, so Australia is like the only country in the world that enforces actual elemental ratios? Ok my bad, I didn't read properly. Yeah US and Europe have this weird P2O5 thing.

 

[Bonsai Nut]

Plants likely remove fertilizer in a 3:1:2 ratio.

Just to complicate things, be aware that plants may require different nutrients at different times of the year, or in different stages of growth. Probably the most notable example is during flowering and fruiting, when the nutrient requirements shift much more towards phosphorous (and potassium).