Fertilizer comparison

I would recommend that the sensitive among you skip the next posting.

> From: Kevin Conlin <kcconlin at cae_ca>
> After Paul Sears brought to my attention the composition of Dupla
> fertilizers (as determined by George Booth) and pointed out that
> various trace elements were in short supply, I did a quick comparison
> of Dupla Drops, Tropica Master Grow, my local trace element mix, and a
> trace element mix that Douglas Skokna found in Houston.  The results
> are as follows, normalized to give a relative iron concentration of
> 1.0:
> Element  Dupla Drops  Tropica  My Mix  Doug's Mix
> -------  -----------  -------  ------  ----------
>    Fe        1.00       1.00    1.00      1.00
>    Mg         (1)       5.57    5.00 (3)  1.35
>     B          -        0.06    0.19      0.13
>    Mn         (2)       0.57    0.29      1.00
>    Mo          -        0.03    0.01      0.03
>    Zn          -        0.03    0.06      0.38
>    Cu          -        0.09    0.01      0.38
>    Co          -          -       -       0.01
> What's interesting about this table is that it shows that Dupla Drops
> are a source of iron only; they are not a significant source of any
> other trace element or micronutrient.  If you also use Duplagan and
> Dupla tablets, Mg and Mn are supplied (as well as the macronutrient
> K), but B, Mo, Zn, and Cu are still missing.

Not to cast aspersions on Paul Sears or Keven Conlin, but how the 
<explective deleted> did you manage to mangle the data so badly and
then draw a conclusion from it?  "Trace elements in short supply"???

Dupla drops are not designed to be used alone - they are designed to
be used with DuplaPlant tablets.  The clause "If you also use Duplagan
and Dupla tablets..." is a bit silly.  If you are stupid enough to not
pay attention to the dosage instructions, you deserve to waste your
money and have your plants die.

Let's review the Dupla analysis yet again:

Duplaplant fertilizer tablets

Ca   5.5 ppm    Mg   0.3 ppm    Na 116.0 ppm   K  2490.0 ppm    P    0.3 ppm
Al   0.4 ppm    Fe 234.0 ppm    Mn  36.8 ppm    Ti   0.6 ppm    Cu   0.2 ppm
Zn   0.6 ppm    Ni   3.7 ppm    Mo   0.7 ppm    Cd  <0.1 ppm    Si   5.7 ppm
Cr   0.1 ppm    Sr  <0.1 ppm    B    6.7 ppm    Pb   0.1 ppm    V   <0.1 ppm

Now how does one draw the conclusion that "B, Mo, Zn and Cu are still
missing"?  Ah, apples and oranges were compared ("normalized to iron")
and it was decided that the concentrations of these elements became
small enough to be declared "missing".  Hey - these are "trace
elements" not "bulk elements".  What do you think "trace" means?  This
also implies that Tropica, Kevin and "Doug" know more about the
correct proportions of trace elements than Dupla.  Tropica maybe, but
I doubt Kevin and "Doug" have done extensive research in this area
other than, perhaps, their plants grow OK.  

I have been using Dupla solely for eight years and my plants manage to
grow quite well, thank you.  My tap water has nothing useful in it
(pretty much pure Rocky Mountain snow melt) so the plants depend on
Dupla for their needs.  If Dupla products did not supply the proper
nutrients, I probably would not have been able to sell $800 worth of
plants last year. 

> From: Andrew Hamilton <andrewha at tafe_sa.edu.au>
> What about the recent post on the analysis of fertilisers, has this been
> done scientifically or is it just speculation. George, if Dupla Drops are
> purely Iron why on earth are they so expensive? Is Dupla saying that plants
> only require Mg, Mn and Fe. Shorly their fertiliser regieme consists of more
> chemicals than these.

Second of all, why do you say Dupla drops are "so expensive"?  If you
compare the "per dose" or "per month" cost of the Dupla regimen and,
say, Sera Florish, you would find that Dupla costs 1/2 as much AND

It's kind of like comparing real perfume at $100 per ounce to "eau
d'toliet" [sic] at $10 per quart.  You're going to smell if you use
either one, but you'll smell better with real perfume and it will last
a whole lot longer.  

George in Colorado With My Hackles Up