Lettuce Handbook - Stock Solutions

Stock Solutions

Two stock solutions are prepared which will be added separately to RO water and will supply nutrients to the lettuce plants while in the pond area. Two separate stock solutions are prepared to prevent certain chemical reactions. These chemical reactions will cause some of the chemicals to form a precipitate and become inactive. The precipitates will not form if mixed one after another with a large volume of RO water.

STOCK A

These chemicals are added to 300 L of RO water

Calcium Nitrate 29160.0 g

Potassium Nitrate 6132.0 g

Ammonium Nitrate 840.0 g

Sprint 330 Iron - DTPA (10% Iron) 562.0 g

STOCK B

These chemicals are added to 300L of RO water

Potassium Nitrate 20378.0 g

Monopotassium Phosphate 8160.0 g

Potassium Sulfate 655.0 g

Magnesium Sulfate 7380.0 g

Manganese Sulfate*H₂O (25% Mn) 25.6 g

Zinc Sulfate*H₂O (35% Zn) 34.4 g

Boric Acid (17.5% B) 55.8 g

Copper Sulfate*5H₂O (25% Cu) 5.6 g

Sodium Molybdate*2H₂O (39% Mo) 3.6 g

Final Fertilizer Solution Concentrations

Macro-nutrients:			Micro-nutrients:
N	8.9 millimol l^-1	(125 ppm)	Fe	16.8 micromol l^-1	(0.94 ppm)
P	1.0 millimol l^-1	( 31 ppm)	Mn	2.5 micromol l^-1	(0.14 ppm)
K	5.5 millimol l^-1	(215 ppm)	B	15.0 micromol l^-1	(0.16 ppm)
Ca	2.1 millimol l^-1	( 84 ppm)	Cu	0.4 micromol l^-1	(0.03 ppm)
Mg	1.0 millimol l^-1	( 24 ppm)	Zn	2.0 micromol l^-1	(0.13 ppm)
S	1.1 millimol l^-1	( 35 ppm)	Mo	0.3 micromol l^-1	(0.03 ppm)