Hydroponic nutrient concentration

GEWZOTH gewzoth at aol.com
Tue Oct 8 14:08:05 EST 1996

Hi everybody,
I'm a hydroponic rookie, I'm running my first hydroponic system with
rockwool (vegetables, flowers). Looking around for infos about the ideal
hydroponic nutrient concentration I got totally confused. There are
different recommendations in different units for the ideal dissolved
solids concentration, e.g.

1: 800 ppm
2: 0.8 - 1 mS/cm

vegetative growth: 
1: about 900 ppm
2: up to 2000 ppm
3: 1.8 - 2.3 mS/cm

Can anybody give me some answers to the following questions:
- Is 900 ppm for slow growing, 2000 ppm for fast growing plants ?
- What is the relationship between ppm and mS/cm ?
- Are calculated (from the N-P-K values) and measured ppm values the same

Thanks for your help - Gunther.
Concerning the pH value things are obviously easier: all recommendations
are close to 6.

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