Question
I attended the workshop last Sunday at Seymour Conservancy in Tacoma on carnivorous plants.  During the talk the presenter said he would be testing Tacoma water to see if it was okay for carnivorous plants.  Unfortunately, I left after purchasing some plants and forgot to check back to see the results of his test.  Can he tell me whether the Tacoma water is okay to use for these plants.  Thanks.

Answer
Hi Alice,

I tested the water before I left, and it came out at 156 ppm.  The water needs to be 50 ppm or lower to be safe for carnivorous plants.  This is pretty similar to our well water at the nursery, and we have to pass ours through a reverse osmosis system.

Bottom line, this is too hard for carnivorous plants.  Nepenthes, Mexican butterworts and Sarracenia are the least sensitive with sundews and Venus Flytraps being the most sensitive.  In a pinch you can use tap water, but long term use would be harmful.  Best to use distilled water or rainwater if we ever get some.

I did check the City of Tacoma's water page to see what your water source is.  Most of the supply comes from the Green River system, then they supplement with wells during the summer.  There's a good chance that during the rainy season the water will be soft enough since they probably shut down the well water.  Portland does something very similar.  Surface water sources in the Northwest tend to be low in minerals.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.growcarnivorousplants.com