Is Softened Water Bad for Plants?

Finally, a question with a simple answer rather than one of those frustrating yes-and-no ones. Is softened water bad for plants? Yes. In general, if you have a water softener that makes life a bit more pleasant in the home, it is not ideal for houseplants.

That’s a definite yes. But then again, note that we said in general. If you want soft water and you like houseplants, there is no reason why you can’t have both.

There are things you can do to avoid the problem, but the first thing to establish is why softened water is bad for plants. Naturally soft water is fine, but then again, whatever the characteristics of your water supply, there will be things to consider.

In this case, it’s mainly to do with the sodium that is used in water-softening systems; sodium chloride, to be precise. That is one chemical that everybody knows about: it’s what we know as plain old salt, and it is not ideal for most household plants.

But that is not to say it kills all plants. There is vegetation around the coastline where the sea has been depositing salt for thousands of years. So, some things can handle it. It’s just a question of which ones, and with a little research, you can find plants that will not fall victim to your fancy 21st-century soft water system. Most of us will immediately hit the internet and find out for ourselves, but there are alternatives. You could look this up in some scholarly book in a library. Or – here’s a radical idea – ask someone who knows these things.

Where do you buy your plants? If it’s from a grocery store, you’re probably not going to find an expert there. No offense, grocery store people, but you can’t be expected to know everything. A nursery or a garden center, that’s where we should be seeking advice. The staff there are doing their job for a reason, and most of them will have a certain level of knowledge. If what you’re asking is above their level, they can put you on to a coworker who does know that sort of thing.

So, Water Your Indoor Plants – But Don’t Use Your Softened Water

Having a water softener system is a great thing, and it doesn’t make sense not to have one just because of the plants. Consider where your softener is located. If it’s inside the house or against the wall right outside, you may have a faucet in the garden that is not affected. The plumber who installed this may or may not have considered the water-softener-vs-plants issue, but anyhow, if there is a faucet out there that uses water directly from your external supply, you’re in luck. Get out there and fill a watering can with the precious non-salty stuff.

Another way of doing this would be to use rainwater: collect what falls out of the sky and runs through your gutters and downpipes. Just put a barrel underneath, maybe with a faucet on it, and you can give the indoor greenery the benefit of what it would have received outside.

Sodium vs Potassium

If you don’t want to go the outdoor route, you may consider a water softener system that uses potassium chloride rather than sodium chloride. While potassium chloride can be beneficial to plants and is even used in fertilizers, it’s that chloride part that can be toxic to plants, so too much of that kind of softened water can be harmful too.

If you want to discuss the whole issue of watering houseplants, a good water softener company will be happy to do so. After all, these are people with homes of their own and indoor plants to look after, so it won’t be the first time they have thought about it.