Tap water varies quite a lot depending
on source and how treated by Water Undertaking. Mine reads 0.06 MS.
Some tap water has a much higher EC.
Salty water would have a very high
EC, not suitable for plants and humans to drink.
The amount of salts contained in tap
water and rainwater have little or no value for the nutrition of
plants, but they do need consideration in the final and total solution
strength administered to plants.
Obviously special hydroponic
nutrients for plants are added to the water supply source and again
this can be accurately measured and regulated continually at each and
every phase and stage of growth.
The residual level of the water
supply must be accounted for in the final total EC value as mentioned
i. e. If the value of the solution
required for feeding the plants at a particular stage of growth is say
1.00 MS then only enough nutrient must be added to the residual water
to bring the total to 1.00 MS.
Example: Residual water source 0.10
MS, nutrient source 0.90 MS =1.00 MS total.
Chrysanthemums require feeding at
different strengths at different stages of growth. This will be
discussed under NUTRITION.