Know what you grow in
In table three, the elemental content of
the nutrient solution in parts per million
(PPM) is given in the first column and the
elemental content of the recovered nutrient
solution after equilibrium with rockwool,
perlite and coir, respectively, after filtration
follow in the next three columns.
For perlite, the only elemental change
was for the element Cu. For rockwool,
elemental change occurred for Ca—not
surprising since Ca is a major constituent
(see table one). Iron is also a major
constituent, but no change occurred. The
most significant changes occurred with coir,
with increases in elemental contents for
the elements P, K, Mg, Na, Fe and B, and a
decrease in Ca. Some of this might be due
to the fact that in the interaction process,
the filtrate was colored with colloidal
100
Maximum Yield USA | September 2012
Table 3. Elemental interaction of rockwool,
perlite and coir brought into equilibrium with
a nutrient solution
Element
Nutrient Rockwool Perlite
Solution
Coir
ppm
Phosphorus (P)
82
80
88
140
Potassium (K)
276
272
288
678
Calcium (Ca)
198
282
192
50
Magnesium (Mg)
42
42
44
64
Sodium (Na)
15
15
19
218
Sulfur (S)
110
108
118
132
Boron (B)
0.26
0.27
0.29
0.70
Copper (Cu)
0.08
0.10
0.28
0.06
Iron (Fe)
1.1
0.8
0.7
2.7
Manganese (Mn)
0.72
0.78
0.76
0.60
Zinc (Zn)
0.28
0.28
0.28
0.27