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PMDD: Doses/ Analysis of PMDD (my way).........

>Date: Tue, 15 Apr 1997 12:36:08 -0400 (EDT)
>From: Tim Mullins <tmullins at telerama_lm.com>
>Subject: PMDD: Doses

>A consensus has emerged on the Conlin and Sears
>PMDD formula: mix with water to make a 1/2 liter solution,
>       1 tablespoon chelated trace mix
>       1 tablespoon MgSO4+7H2O
>       2 tablespoons K2SO4
>       1 tablespoon KNO3  (may vary, depends on nitrate)
>        [Thanks to Steve Turner and Onis Cogburn for mix-fix]
>Now how about dosing? Does anyone have any comments
>on these revised sections of my previous "PMDD: Sources and
>Doses" post?
COMMENTS: revised sections of my previous "PMDD: Sources and
>Doses": The text is somewhat long. I will take a  closer look later.

Here is my analysis of the component of PMDD (my way....), which I hope
to use it for determining the dosing of PMDD.

REMARK 1: I think PMDD works only on plants that get their nutrients
from the water. Plant which get their nutrition from the soil will not
havwe the same growth responds.

REMARK 2: I don't use test kits, since these are very expensive .
Instead I look at the nutrient deficiency symptoms of the fast growing
plants ( Hygrophila spp.)

In the following calculations I am using the MKS system

The MAJOR elements in a plants are: 

2)Phosphorus (P) 	
3)Potassium (K)		
4)Carbon (C)		
6)Oxygen (O)
7)Calcium (Ca)		
8)Sulfur (S)		
9)Magnesium (Mg)	
10) Iron (Fe)

MINOR element:

11)Sodium (Na)
12)Aluminium (Al)
13)Silicon (Si)	
14)Chlorine (Cl)
15)Gallium (Ga)
16)Cobalt (Co).	

1 tablespoon chelated trace element mix (7.8grams)
COMMENTS: Probably to much but has probably all the MINOR ELEMENTS.
MAYBE 1/4 tbp is enough.
1 tablespoon MgSO4+7H2O:16.6 grams MgSO4
MgSO4 molecular weight (mw): 120.37  => 12.0 grams MgSO4 in 1000 ml
=>0.1 N MgSO4 in 1000 ml
	1 tablespoon =>16.6grams MgSO4 in 1000 ml =>0.14 N MgSO4 =>0.28N MgSO4
in 500 ml
2 tablespoons K2SO4: 43.6grams K2SO4 =>2.5N K2SO4 in 1000 ml => 5N K2SO4
in 500ml.
K2SO4 mw: 174.27 : 17.4 grams K2SO4 => 0.1N K2SO4 in 1000 ml
COMMENTS: Plenty of K and S (MAJOR ELEMENTS) , maybe to much.
1 tablespoon KNO3=>17.6 grams KNO3 =>0.17 N KNO3 in 1000 ml =>0.34 N
KNO3 in 500 ml.
KNO3 mw: 101.11 =>10.1 grams KNO3 => 0.1N =>17.6 grams KNO3=>0.17 N KNO3

OVERALL COMMENTS: PMDD has not enough Ca (especially in soft water). I
think it would be better to put  chelated Fe separate since this is one
of the more important MAJOR elements.

I would make the formula this way:

For 1000 ml water :

1/4 tablespoon chelated trace element mix (1.95 grams)
1 tablespoon MgSO4+7H2O:16.6 grams MgSO4 in 1000 ml =>0.14N MgSO4
1 tablespoon K2SO4: 21.8 grams K2SO4 in 1000 ml => 1.25 N K2SO4 
1 tablespoon KNO3=>17.6 grams KNO3 =>0.17 N KNO3 (or use Ca(NO3)2 in
soft water).

Additional: 1 tbp (10grams) FeEDTA 4.5% in 1000 ml =>0.45 grams/1000ml
=>450mg Fe/1000ml =>450ppm.


I have not tried this formula but, with these molarity calculation is
easier to read (for me) the amount that you are dosing.

If you have any comments, write to me. I am interested if my post was
clear and if there is any errors in the Molecular Weight and

ir. Jos K.K. Liem Horticulture (Wageningen) 
E-mail: liem at direct_ca Ph:+1-604-525-7229
New Westminster BC CANADA