Know your Plants
Plant Nutrient Strength requirements
For normal plant growth hydroponics nutrient solutions are in the range
0.5 to 4.5 mS/cm. Wilting, leaf scorch, bolting and other abnormalities
will be experienced when conductivity levels are outside their preferred
range.
Because most of the materials in water used in hydroponics are salts
the mineral content of a nutrient solution is sometimes referred to as the
Total Dissolved Solids (TDS) in the nutrient solution. The convention in
hydroponics is to use Electrical Conductivity (E.C.) as the units to measure the strength of
a nutrient solution. See Know your meter
Plants tend to fall into three groups requiring a high, medium and low
conductivity.
Leafy greens, lettuce, beans and most herbs require a low conductivity 0.7
to 1.5 mS/cm in winter and 1.5 to 1.8 mS/cm in summer.
Cucumbers, melons, many ornamentals and some cabbage-related crops
prefer medium conductivity of around 1.6-1.8 mS/cm in summer and 1.8-2.2 mS/cm in winter.
Tomatoes, peppers and eggplants prefer a stronger Conductivity in the
order of 2.5 - 3.6 mS/cm in
summer and 3.6 to 5.0 mS/cm in winter.
For more detailed information on optimum conductivity levels for different
plants read Hydroponic Gardening by Steven Carruthers pages 12 & 13
(ISBN 0 85091 557 0).
Copyright © 1996, 1997, 2001 TPS Pty Ltd
