Re: Fertilizer comparison

Plant wholesaler and Dupla spokesperson George Booth writes... ;)

>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

Not missing but maybe in short supply.

The micronutrient mix that I use and that I believe Kevin uses is
produced for hydroponic gardening and the proportions of these
elements are pretty standard. I'd be interested to know why DUPLA
deviates from these ratios.

The concentration of boron for instance in dry tissue in most higher
plants is about 20% that of iron. So for every ppm iron supplied by
your Dupla products you might expect, maybe not 0.2 ppm exactly, but
perhaps 0.1 ppm boron. Similarly, compared to iron, zinc is about 20%
by weight, manganese 50%, copper 6%, and molybdenum 0.1%. For our mix
the ratios of Cu, Zn and Mn to Fe are a bit low, Mo is much higher
and boron is right on. Of course the concentrations needed in the
water or medium for good growth may be slightly different from the
final makeup in the plants.

Now review the Dupla analysis again and note that the ratios of Cu,
Zn, B and Mn to Fe are substantially lower than dry tissue ratios.

>I have been using Dupla solely for eight years and my plants manage to
>grow quite well, thank you. 

The proof is in the pudding George and your plants are great.

>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. 

I don't believe it.

>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.  

Are you calling Kevin's concoction the Aqua Velva of fertilizers?

Karen Randall said....

>I think, from speaking with Kaspar Horst, that the reasoning
>behind their specific mix of minerals, (and he stresses that both
>should be used together) is that the others are _usually_ found in
>tap water in adequate amounts.  Obviously, there will be a great
>deal of variation between one tap water supply and another.

Not all of us get our water from the Rhine.

Dave Whittaker                       ac554 at FreeNet_Carleton.CA
Gloucester, Ontario                  dwhitt at magmacom_com