Question
Hi Jeff,

I have a very serious concern... I usually filter my own water with a RO unit, which works fine.

However, next year I磍l be living in Taiwan for 12 months, my sister will probably get in the flat in that time, however I don磘 want her to need to filter RO water each and everyday, it will be too much of a hassle, especially in summer. (where I need 50L water in a hot day)

This spring I will repot all my plants. They will be watered with RO water (13ppm) until January next year. Afterwards, for 12 months, watered with tap water, which is around 200ppm.

My question is: how much would it affect the plants and their growth?

Knowing that after I come back, I would repot again. So in fact the plants would be watered 1 full season (winter to winter) with tap water, then back to fresh soil and RO water.

Thanks for your comments!

Cheers,

JP

Answer
Hi JP,

The short answer, teach your sister how to use the RO unit.  Besides, it makes great drinking water too!

A quick story.  When we first moved to our current location for our nursery in 2005 we came from Portland, OR which has this pristine water source in the Cascade Mountains.  The water comes out of the tap at about 20ppm.  We could use the tap water with no concern.  We moved out the country and our water source was well water.  It was around 150ppm with most of the mineral content being calcium and magnesium.  At that time we had no choice but to use the well water untreated.

That first summer here the following happened before the return of the rains in the fall.

Nepenthes and Mexican Butterworts, no effect.  They looked fine.

Sarracenia all had browned lid edges by September (we moved there in July).  This was all of them, not just the Flava and Oreophilas.  Lots of algae growth was present on the soil.

Hardy sundews and tropical sundews were showing white deposits on the leaf edges, and many were in marked decline.

Regular Venus flytraps were not looking well, and we lost nearly all of our red flytraps.  Overall we lost close to half our Venus flytraps and hardy sundews.

Hard water causes a slow decline in many plants, with sundews and Venus Flytraps being the most sensitive.  200ppm is pretty high, and there's a good chance that by the time you got back to Germany only your Sarracenia would be alive. :(  You'll need the RO unit.

Good Growing!

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