Hi, Fred. Plants vary more in the volume of nutrients they use per mass than the ratio. On average, plants will use around 6x as much N as P and about 3/5 as much K as N. Because P and K are reported as the % by weight of phosphorous pentoxide and potassium oxide respectively, the reported amounts on packaging need to be multiplied by factors of .43 for phosphorous and .83 for potassium. So 3:1:2 ratio fertilizers actually supply P and K relative to N at a ratio of about 3: .43: 1.66, which is very close to the 6x as much N as P and 3/5 as much K as N.

You'll encounter a few plants that prefer something quite different than the all purpose 3:1:2 ratio, but usually you can still use the 3:1:2 ratio fertilizer and accommodate the plant's known preference by supplementing with another nutrient delivery vehicle. E.g., hibiscus doesn't like much phosphorous, but does like more potassium than the average plant, so when I fertilize Hibiscus, I add 1/4 - 1/2 tsp of KCl to a gallon of what I normally fertilize with.

If we assume that bonsai practitioners recommend 1:1:1 ratio fertilizers, we need to keep in mind that the fertilizer's ratio or NPK %s don't determine how much N your plant gets - YOU do. So if you see signs of a N deficiency, what do you do? You add more N. If you're using a fertilizer with a ratio that closely mimics usage, all is fine - your plants get enough N, P, K, and the rest of the nutrients, assuming they're IN the fertilizer and PROPORTIONED to N usage. If you're using a 1:1:1 ratio and are keeping up with N needs, it follows that you'd need to be supplying more P and K and likely all other nutrients than necessary, contributing to an unnecessarily high level of EC/TDS in the soil solution and opening the planting to the potentiality of antagonistic deficiencies, which would also relate to watering habits.

I don't usually listen too closely to experts that don't tell you WHY they do what they do or why you should mimic their strategies. If you do a net search with the words walter pall 20-60, you'll discover that he applies 20-60 times the amount of N as the average grower by fertilizing at twice the rate recommended every 10 days. For years, I've been offering comments that reflect my practice of fertilizing with 9-3-6 at 2-3 times the recommended rate weekly (2-2.5 tsp/gallon when mean temps are 65-80*), and I'm thinking you've seen some of my trees that illustrate they're doing fine in depts. related to growth rate, health, appearance.

Alex Shigo, PhD (a really famous tree guy - you should know him if you don't already) said, "A tree [plant] that is not growing is dying". And that can only be true. There is no balance in nature. A plant that is turning sunlight into more energy (food) than it uses is growing. A plant that ISN'T, one that's using more energy than it's manufacturing will always die unless the trend is reversed. A plant's state of vitality is a byproduct of its metabolism, so trees that are growing well are much easier for bonsai practitioners to keep happy/healthy/attractive.

The next time someone recommends a 1:1:1 ratio fertilizer - ask why it's recommended. The answer will likely be because other fertilizers (like 3:1:2 ratios) have too much N. Then hit them with, "Isn't it the grower that determines how much N the plant gets?" and see how the question is fielded.

Discussions about nutrition come up so frequently that I actually took a few minutes to consider how a hypothetically perfect nutritional supplementation program might be described. This is what I came up with:

Nutrient
Supplementation - Objectivity

Whenever we discuss what is or isn't an appropriate part of
the methodology we use to make certain our containerized plants get all the nutrients
essential to growth and good health, we would probably first want to be sure
our objectives are on target. It's difficult to argue with the idea that our
focus in supplying supplemental nutrition to our plants should be on ensuring
all the nutrients plants normally assimilate from the soil are A) IN the soil
and available for uptake at all times, B) in the soil at a favorable ratio -
that is to say in a ratio that mimics the ratio at which the plant actually
uses the nutrients, C) at a concentration high enough to ensure no nutritional
deficiencies, yet still low enough to ensure the plant's ability to take up
water, and the nutrients dissolved in that water won't be impeded (by a high
concentration of solubles in the soil solution).

At
this point, you can accept these premises as worthy goals or argue against
them. If accepted, we should then necessarily examine our efforts at
supplementation in the light of whether or not our efforts bring us closer to
or limit our ability to see the goals implemented.

***********************************************************************************************

Obviously, 1:1:1 ratio fertilizers wouldn't pass muster because no plants use nutrients in a 1:1:1 ratio which also ensures the EC/TDS of the soil solution will be higher than necessary in order to prevent deficiencies of at least N and K, but most likely other nutrients not supplied as a function of N usage.

Is this going to kill your plants? No

Make them observably deficient in growth rate, productivity, appearance? Possibly, but not likely for the average hobby grower.

Is there a better way that affords plants greater opportunity to realize more of their potential? Yes

Al

It's actually quite ironic that in the end, the growers who advocate 1:1:1 fertilizer (usually because 9:3:6 or 24:8:16 have "too much N") are just wasting money and flushing fertilizer down the drain, using almost 10 times more 1:1:1 than they'd need if using 9:3:6, for example.

I've seen countless members throughout gardenweb decry foliage pro because it has "too much n" - and really, many of these members have very nice plants and a good understanding of media/pwt/etc and years of experience growing. So they just flush sufficiently for the amount they fertilize, and it goes out the drain. They can't see past 9 vs 1. You just need a smaller measuring device, and 1/9th the amount of fertilizer.

I find 1/4 tsp is the smallest I really ever need. My set of stainless steel magnetic measuring spoons 1/4 tsp, 1/2 tsp, 1 tsp, 1/2 tbsp, 1 tbsp is infinitely useful and was really cheap. It's one of my favorite things.

fred, you asked specifically if 3:1:2 was "scientific fact", and it was kind of touched on above - it comes from tissue analysis of plants, and that's effectively how much n:p:k was found in the plants (subject to various rational, required conversions) - that's the ratio that they took out of the soil.

Daniel

Thanks Al and Daniel. Very much appretiated....:-)

Yes I know the WP technique very well and actually are in discussion on another forum about that to. That technique just doesn't make sense to me at all....

I'm the first to declare that my knowledge on fertilizers and it uses are very basic at this stage (but I'm learning fast), so I cant say its wrong. It just seems to me more of a waste of fertilizer than actually feeding the trees basic needs.....? He uses a "general fertilizer that is noted as being good for all plants" and then feeds at that high rate. My logic says to me the plant only takes up what it needs, and the rest is wasted. That means a LOT of waste if you mix the fert at that concentration. I don't see the point....? He also warns to only do that with a very modern and open media together with lots of water, but my point of wastage and fertilixer limitations still holds for me....?

Rather get the right stuff that contains everything, and feed at the recommended rate ....or am I missing something here...?

Can you clarify for me please. Why does he actually do that? What does he gain from it, as apposed to using a good well balanced one at recommended rates...???

(I'm saying the above with the following facts in mind.... plants can only grow according to their genetic make up (no faster), and that they only take up what they need at that moment)

His point is that most bonsai trees are horribly under-fertilized; and he uses the method he adheres to as a way to remedy that. I was essentially doing what he's doing (and liking it) long before I came across what he said. Because it works, I don't look at it as a waste, rather, I look at it more as a necessity if I'm to view things from the perspective of what's good for the plant. Some might say the high dose of fertilizer promotes rank (big leaves/long internodes) growth, but I keep that in check in the more developed trees by partial or total defoliation + leaf trimming and pruning to promote the maximum number of growing points on the tree, which serves to divide a reduced volume of energy production among more growing points, which = small leaves/ short internodes.

There is a significant advantage in having trees that put on a lot of growth (especially developing trees), even if you do remove a very large fraction of it (trees you're serious about ramifying).

Plants do take what they need and leave the rest (every time I write that I get that old Joan Baez tune stuck in my head for a whole day. The Night They Drove Old Dixie Down), but what if they aren't getting what they want? That question brings us back around to what I wrote above:

Nutrient Supplementation - Objectivity

Whenever we discuss what is or isn't an appropriate part of the methodology we use to make certain our containerized plants get all the nutrients essential to growth and good health, we would probably first want to be sure our objectives are on target. It's difficult to argue with the idea that our focus in supplying supplemental nutrition to our plants should be on ensuring all the nutrients plants normally assimilate from the soil are A) IN the soil and available for uptake at all times, B) in the soil at a favorable ratio - that is to say in a ratio that mimics the ratio at which the plant actually uses the nutrients, C) at a concentration high enough to ensure no nutritional deficiencies, yet still low enough to ensure the plant's ability to take up water, and the nutrients dissolved in that water won't be impeded (by a high concentration of solubles in the soil solution).

At this point, you can accept these premises as worthy goals or argue against them. If accepted, we should then necessarily examine our efforts at supplementation in the light of whether or not our efforts bring us closer to or limit our ability to see the goals implemented.

Because I see no indication the plants are having difficulty taking up water, I have to think I'm within the parameters I set as boundaries of the hypothetically perfect nutritional supplementation program. I suppose, if I was serious about finding where a species boundaries lie in terms of fertilizer concentrations and intervals between applications I might stick with the week-long intervals and increasing solution strength until I DO see indications that I'm over-fertilizing, and then back off the solution strength enough that I KNOW I'm not taxing the plant's ability to deal with EC/TDS of the soil solution, but that would take a lot of time and effort. Instead, this is one of those areas where I'm willing to compromise and be happy with the current MO.

I'm not suggesting that you (or anyone else) follow my lead, or that because I like the results I get it's not possible that you might find a better way. I'm 100% certain that the way I fertilize can be improved on in some ways, and I encourage anyone to keep looking for ways to improve on what they (or I) do. Hopefully, from what I said you'll know that if you choose to significantly increase the recommended dosage of 9-3-6 (if you're flushing the soil regularly), it's not likely to end in calamity.

I have a couple hundred trees (whittling that down - no pun intended) + another 30 - 50 plants I fertilize regularly in summer and about 100-125 all winter. At the rates I fertilize, a gallon ($50usd) lasts me about 2 years, so my fertilizer outlay is only about $25 annually.

I hope that helps, Fred.

Al

Can you speak about the pros/cons of manipulating frequency / dosage?

If I understand Walter Pall's method correctly, it's: supply large dose of nutrition ("4X recommended"), every 10 days, and flush every single day.

Why would Walter Pall feed at 4X every 10 days, instead of say 2X every 5 days? Wouldn't everything get flushed before it could be used? Or does waiting make the roots more eager, and thus they can absorb it faster and more effectively than if provided at lower doses more often?

Would growth differ if nutrition was supplied at 2X every 5 days, or 1X every 2.5 days?

Daniel