Throughout the various plant care articles on this website, the term Reverse Osmosis Water is used regularly, as it is what is the best choice for carnivorous plants (aside from rain water).
So what exactly is Reverse Osmosis Water (RO) & Why is it good for carnivorous plants?
In short, RO water is super filtered water that is processed through a special water filtration system. It is about as pure as water can get after removing all chemicals, minerals, additives, etc. This is achieved by forcing water across a super fine semi-permeable membrane allowing only the most pure water to pass through. This leaves the perfect water for not only your plants but also for drinking.
The goal of using RO water for carnivorous plants is to have all harmful chemicals like chlorine, salt, minerals removed from the water so it does not damage the root system of your plants.
The biggest killer of carnivorous plants is tap water because of these harmful additives – or natural minerals that exist in drinking water in various areas around the world.
There are plenty of companies that explain the details of how Reverse Osmosis works including ESP water products (here). The goal of this article is just to explain why it is important to use filtered water if possible.
Most people that have a few plants are fine with collecting rain water, however larger growers and hobbyists prefer to install RO filters if possible.
How expensive is Reverse Osmosis filtration?
In recent years, the cost of Reverse Osmosis filtration systems has become more affordable and easier to install. However, it’s still not cheap.
Inexpensive systems start around $125 and go higher than $500 depending on brand, build quality and number of stages in the filtering process. A consideration when purchasing an RO system is the ongoing costs of the filters. Expect to around $50 or more per year on replacement filters, depending on how much you use the filter.
If I cannot install or afford Reverse Osmosis, what options do I have for my plants?
Many people choose to collect rain water. However, you should never use water that is from roof runoff, as the chemicals that are in roof coverings, tiles, tar, and other roofing materials often seep into the water and will kill your plants (eventually).
The best alternative to Reverse Osmosis water is often sold in grocery stores as “demineralized” water which is used for Irons, floor steamers, clothing steamers etc.
While some people choose to buy distilled water by the gallon, it is not always the safest option for plants. Often these waters are advertised as distilled because they remove a large percentage of chemicals but may still contain some trace minerals.
The biggest misconception is watering plants with bottled drinking water or purified water (Ozarka and other branded waters). These often still contain trace minerals that will eventually kill carnivorous plants.
One side note to the above bottled drinking water for watering plants is this: If you face the option of letting your plant die because it dried out ro using bottled water ONE time, you’re usually ok to save the plant with some purified drinking water. Generally speaking, watering the plant once with bottled water will not harm it.
But it is important to know – watering your plants with TAP WATER just ONE TIME will likely kill the plant due to additives and minerals in the water system.
Is hard water bad for carnivorous plants?
Hard water contains minerals that will eventually build up in the soil that your plants are potted in. This is one of the reasons we do not recommend using tap water because of the mineral content that is likely to be present (soft or hard water).