FlytrapCare Carnivorous Plant Forums

Does anyone know what the average EC reading for for CP's should be? I have some coco coir I want to use and after everything I have read it is imperative to wash well prior to using with CP's.

Most of us don't use EC readings for measuring/estimating appropriate media, we use the more general TDS reading, which uses EC to determine it. Maybe TDS and EC are the same thing, two sides of the same coin. We buy the inexpensive TDS meters and shoot for ~ 50 ppm or less if the makeup of the water is unknown. Testing the runoff from media can give us an idea of how appropriate the media may be.
With coir, the coconut palms typically live close to the ocean and absorb a lot of salt from the spray and uptake from the roots. After harvest, it's generally observed that coir left in the open for three monsoon seasons will allow virtually all of that salt to wash away. However, most suppliers don't have the room to store coir for years, and, since it's usually added as a supplement to soils, there's usually not enough salt to cause a problem for regular plants, and most of what's left is likely flushed out in the first watering. Obviously, carnivorous plants are not regular plants.
The reason that a strong suggestion exists to rinse coir well is due to this absorbed salt. I know a few growers that love coir, and their only complaint is that it sometimes takes days, if not weeks, of soaking, rinsing, testing, and repeating to get the TDS down to an acceptable level. Most of them will do that with tap water, with a final few flushes of rain or distilled water to get the runoff down to almost 0 ppm TDS.

ChefDean wrote: ↑Sat Aug 26, 2023 11:08 am Most of us don't use EC readings for measuring/estimating appropriate media, we use the more general TDS reading, which uses EC to determine it. Maybe TDS and EC are the same thing, two sides of the same coin. We buy the inexpensive TDS meters and shoot for ~ 50 ppm or less if the makeup of the water is unknown.

Just for the record, a lot of cheap TDS meters have a switch to change to EC mode. One of mine does. Doesn't mean I'm going to use it and break with tradition, but it's there. I checked with Google and you get from TDS to EC by doubling the TDS and dividing by 1000. I just tried my meter in tap water in both modes: PPM was 64 and EC was .136, so Google's rule of thumb is pretty good. And you don't need a lot of mental gymnastics to do the conversion in you head. Using the rule, I'd go with EC less than .100 for CPs.

I learn something new every day, thanks Evenwind. Now I gotta go check my cheap TDS meter.
Edit: Mine does not have an EC feature, but will tell me the temp of what I'm measuring in °C or °F.

I bought a TDS meter from Amazon and did not realize it has an EC with it.
https://www.amazon.com/gp/product/B06XK ... UTF8&psc=1