Are you safe to water your lawn with soft water? Will the water softener damage the grass? Does soft water kill plants?
In short, soft water is bad for plants. Soft water is loaded with sodium, and plants can only take so much sodium before they die.
In this article, we’ll talk about exactly why that is, and what you can do to make sure that you get rid of your hard water while keeping your plants healthy and thriving.
Why Do Plants Die from Soft Water?
As we said above, soft water is loaded with sodium. Plants that are watered with sodium eventually begin to form a layer of salt across the soil bed. It’s like how dirty skin can clog your pores -- except, unfortunately, even worse. Water and healthy nutrients can’t reach the bottom of the plant, so it eventually withers and dies.
Additionally, if the salt levels in your soil become too high, then other plants won’t be able to grow, either. If you try leaching -- frequent watering to avoid salt buildup -- with soft water, you’re going to devastate your soil, particularly if you don’t
The Math Behind Why Soft Water is Awful for Plant Life
One of the top articles on this exact topic states the following regarding soft water:
“Naturally, we don’t want to give our plants salt water. But since soft water barely registers with sodium, it’s much more similar to rainwater than your other options, like hard, chlorinated tap water. So yes, soft water is safe to give to your plants.”
This simply doesn’t make any sense at all, and it’s misleading consumers and environmental advocates alike. Soft water is sodium-filled water. Using a salt-based ion exchange softener will result in roughly 20-30mg per 8oz of water, for most people with average hardness levels.
According to SalinityManagement.org, “Most plants will typically suffer injury if sodium exceeds 70 milligrams per liter in water, or 5 percent in plant tissue, or 230 milligrams per liter in soil, in the extract from a saturated soil paste.”
Now, of course, 30mg is less than 70mg, but that means if you have a potted plant, the sodium will only take twice as long to build up in the soil, pushing it past the 5 percent in plant tissue or 230mg per liter in the soil. This is also true for your lawn, especially if you -- like most people -- don’t have some sort of water drainage system for your lawn.
If you don’t take our word for it, listen to Penn State horticulture expert Professor J. Robert Nuss:
“Plants do have a widely varying tolerance for softened water… In many cases, water from a mechanical softener has a harmful effect on plant growth."
One Solution: Get Rid of the (Ion Exchange) Water Softener
Now, how can you keep your plants healthy? One way is to get rid of the water softener -- not to throw it out, per se, but to install a bypass spigot so that the hard water never becomes soft water.
The only drawback with this is that it can be kind of expensive, since you’ll have to add it on to all of the other costs associated with buying a salt-based ion exchange softener. Depending on where you need it installed, the average cost is an additional $225.
Keep in mind that’s an additional $225. You’re also going to have to spend upwards of $400-500 a year on salt, the same salt that’s killing your plants.
And, if you have indoor plants and an outdoor spigot, you’ll have to fill up a water pail from the outdoors spigot, which can be an unnecessary pain for some people, especially in the winter months.
That brings us to our next question…
Is Hard Water Bad for Plants?
Generally speaking, bad water is bad water, no matter what contaminants it has. However, depending on the hardness level of the water, the calcium and magnesium in hard water is actually good for plants, in the same way that magnesium and calcium are good for your body.
That doesn’t mean that all levels of hard water are good for plants. Just like with high sodium levels, high levels of magnesium and calcium can build up in the soil and cause damage over time, so there’s unfortunately no easy answer.
Rainwater is actually the big winner, since it’s what plants naturally need. However, hard water outranks soft water by a significant amount. While rainwater is technically “soft,” it hasn’t been treated with sodium -- which is the real plant killer here.
Conclusion: Is Softened Water Bad for Plants?
Does soft water kill plants? Yes.
Soft water is bad for plants if it’s been treated with sodium.
Over time, a thin layer of sodium builds up on the soil bed, stopping water and nutrients from flowing to the roots. This can and will happen with average hardness levels of only 10 grains per gallon after it’s been softened by sodium.
How can you get around it? Well, mostly just by using a bypass spigot so that you don’t water your lawn or plants with the sodium-treated water. On top of all the other costs of maintaining a sodium-based softener, this can get very expensive.
Another option is just to purchase a template assisted crystallization water conditioner like those here at FilterSmart. They change the way that calcium and magnesium interact with surfaces to stop limescale production, but they don’t actually get rid of that magnesium and calcium. That way, it’s much, much safer to water your plants with water that’s been filtered by one of our systems.
So, will the water softener damage the grass? That depends on the type of water softener you own.
Keep in mind, however, that extremely hard water will still be bad for your plants, because the magnesium and calcium can also build up over time, leading to unhealthy soil. Your best bet is rainwater, of course, since that’s the most natural way that plants can be watered.
In the hierarchy of healthy ways to water plants, though, hard water significantly outranks soft water. Why not save the money you’d have to spend on a bypass spigot and just buy a conditioner that’s lower maintenance in the first place? We even offer a 90 day satisfaction guarantee. You can’t go wrong.
