Question
Hi, I finally got my drosera regia delivered yesterday from your company. It is currently repotted on a terra cotta pot from your suggestion. What do you think of using  zerowater filter that can bring the ppm level to zero to water this plant?  Is zero ppm dangerous for this plant?

Answer
Hi Rickey,

Let's back-up here a bit to understand the concept with water for carnivorous plants.  Most cp come from areas where they have spring water that is very pure (very low mineral content) that leaches away most nutrients from the environment.  This is partly why you get carnivorous plants in these areas is that their is so little nutrients present.  They catch insects to get what is lacking in the soil.  Rainwater has no minerals in it either, so that further leaches the soil.  Carnivorous plants are so well adapted to these conditions that if they are put into the normal higher nutrient/mineral conditions that regular plants are used to, it burns their roots and accumulates in their tissues killing them.

Because of all this, in cultivation, carnivorous plants should be watered with water that has little to no mineral content.  Water with lots of minerals is referred to as "hard water", and most of the country has hard water for tap water if their water comes from wells.  This is why most tap water is problematic for cp.  People always think it's about the additives like chlorine and fluoride, but those cause less harm than the minerals.  The easiest source of "soft water" is rainwater, or water purified by steam distillation, or "distilled water".  Other ways to get the minerals out include reverse osmosis filtering, or chemical resins that soak up the minerals like calcium and magnesium.  That's what's in ZeroWater filters.  They call it ion exchange.  Simple carbon filters like Brita, Pur and filters on refrigerator water dispensers don't remove minerals.

So, the long-winded answer to your question is that your ZeroWater filter is great to use for all of your carnivorous plants.  If you bought one of the units that come with the TDS meter you can test your tap water to see if it might be ok.  If you live in Western TN, I can almost guarantee your water is too hard since the bedrock is limestone.  However if you were in the Eastern TN, in the Appalachian range, say Knoxville area, your water may be fine.  Reservoirs in the mountains tend to have very pure water.  One example from that area would be Asheville, NC.  Their water is great; it's very soft.

Good Growing!

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