Zarniwoop

I did not mean to say it was a comprehensive test. I meant that it is quick and easy and useful. If you get a very low TDS reading then you know it has not been washed with seawater, for example. Another example is that sphagnum moss peat should not be as high as the Westland brand above. Many of us have had bad experiences with Westland (but some people have found it ok - possibly batch variation, possibly something more complex). A meter costs £5 and the test takes as long as it takes you to mix the media with rainwater. I would be interested to hear of anyone growing Sarracenia at their best in water with a TDS measurement much over 100ppm.

Hi Alexis. Sorry, I did not understand what you wrote. A high concentration of which dissolved salts / inorganics found in potting media are ok for Sarracenia?

Exact naming is impossible, unfortunately. Hidden genes are always there. This is why labels are so important, sorry.

It shouldn't be so hard to find Sarracenia media! TDS (total dissolved solids) is a conductivity measurement so a measure of how much ionic content in a solution i.e. the amount of salts dissolved (note that 'salts' is not just sodium chloride). It does not indicate pH, nor organic nutrients in the solution. Nor does it give a measure of cation exchange capacity, nor any idea of which minerals are in solution. However, it is quick and easy to measure with a cheap TDS meter and is probably the first best quickest indicator to see if a certain media is going to be worth trying for something like Sarracenia. Generally, I think below about 50ppm is good. Here are some tests for some recent media I obtained after only an hour in solution of the roof collected rainwater, in ascending order: Tile roof collected rainwater: 30ppm Klasmann-Dielmann Lithuanian fine sphagnum peat: 30ppm (and the 'best looking' peat I have ever seen) Melcourt horticultural potting grit: 45ppm Perlite: 70ppm (note that it is possible this was slightly contaminated by a cute young cat that seemed to need a litter tray in my greenhouse) Melcourt Growbark Pine: 95ppm Melcourt Composted Fine Bark: 115ppm (contains quite big pieces of bark in comparison with Growbark) Westland sphagnum peat: 200ppm coirproducts.co.uk coir block 5kg: >1000ppm It would seem that TDS reading is inversely related to how easy it is to get hold of the media. (I wonder what became of Davion?)