When it comes to plant care, the most important thing about it is proper watering. It’s not just the frequency of watering that mater, it’s also the water itself. Learn what is the best water for indoor plants, what you need to think about when it comes to water, and what kind of water you should use with specific plants.
Learn the benefits and disadvantages of tap water, rainwater, aquarium water, distilled water, water from the stream, bottled and filtered water. Once you know what each one offers you’ll be able to choose the best water for your houseplants. Plants have different needs and while one type of water will work excellent for some plants it can mess up another type of plant.
What is the Best Water for Indoor Plants?
For people that are just getting into plant care, tap water from the pipe is usually the first and only logical choice. And most of the time, this choice is OK.
But as all plants are not made the same, tap water quality can vary greatly from area to area. The mineral content isn’t the same across the board, nor is the quality of water.
If your tap water is heavy in minerals and chemicals, plants like calathea will quickly suffer. Plants like calathea are pretty sensitive. On the other hand, water your pothos with the same water, and it can thrive. If you have plants sensitive to chemicals, you will need to find an alternative solution to tap water.
While many plant growers suggest leaving your water sit overnight to “fix it”, before watering your plants, that water still might not be good enough for your sensitive plants.
We do recommend letting the water sit as well, as it will dechlorinate at least. And it will get to room temperature, which is great. Some heavy metals will be more concentrated at the bottom so that you can avoid them a little. But this still won’t solve the heavy metals issues, water being too hard, or having other issues. This really depends on the quality and mineral content of your tap water.
Rainwater, distilled water, filtered water, or aquarium water are a better choice if you want your plants to thrive and not see their foliage damaged.
How to Know if Your Tap Water is Good Enough?
You can do a few things to assess if your water is OK for some of your more sensitive plants. While plants do need magnesium and calcium, too much of it can cause a few issues.
Water that might be too hard is easy to spot. If you have to frequently clean your faucets, pipes, or even appliances (water kettles) because of white depositions on them (those are limescale depositions), you have hard water. We live in an area with heavy water and have to wipe limescale deposition off of faucets almost daily.
If you water your plants with water that is too heavy in minerals like magnesium and calcium, those will build up in the soil. If your water is extremely hard, you might even see white crust, not fungus, but mineral deposits, on top of your soil.
As more of the minerals get deposited in the soil, they will affect the soil’s pH levels (making it more alkaline) which your acidic soil-loving plants won’t appreciate. The mineral buildup in the soil can also make it harder for your plant to get the nutrients it needs.
If your water is too hard, you will need to find an alternative. You can also regularly flush the soil with distilled water to eliminate some mineral buildups.
Can you use a water softener to solve this issue?
No. While water that has been run through a water softener won’t immediately harm your plants it will cause a lot of damage long term.
Water softeners work by removing calcium and magnesium ions from hard water and replacing them with sodium ions. The levels of sodium content in softened water are too high for houseplants. High salt concentrations in the water can cause wilting, damage on the leaves, dry leaf ends, and stunted growth.
What about chlorine in tap water for plants?
Chlorine gets added to water to keep it safe for human consumption. It gets rid of all the microbes and harmful bacteria.
If the chlorine concentrations in your tap water are too high, you shouldn’t water your houseplants right away. Chlorine can damage the more sensitive roots.
If you run your tap water and smell the chlorine, you can be certain there is too much water in the water for your houseplants.
You should let your water sit for a day before using it to water your plants, thus giving the water time to dechlorinate (chlorine will evaporate from the water over time). Filtering the water will also have the same effect.
What about heavy metals, other minerals or flouride?
Heavy metals and fluoride can’t be removed from the water from letting it sit. While heavy metals will concentrate on the bottom, and you can avoid heavier concentrations if you only use water from the top, fluoride will still be an issue.
That said, concentrations of these should be relatively low in your drinking tap water (this varies from location to location).
Flouride does the most harm to plants that are sensitive to fluoride. Spider plant, a hardy plant, is fairly susceptible to fluoride, its buildup. If your water has high fluoride content, your spider plant will develop brown tips.
You can have your tap water tested to see what kind of water you have. If your water is within acceptable norms, you can use it for most plants.
We still recommend using filtered, distilled, or good rainwater occasionally to flush the soil and remove any potential buildup of minerals.
Rainwater Can Be The Best Water for Indoor Plants
If it works outside with the plants in the wild, it must be good for your indoor plants as well, right? Yes, but there is a but.
If you live in an area with high population density or near an industrial area, the rainwater won’t be ideal. For one, there will be impurities as pollutants get “washed off,” and also, the pH levels might be off (acidic rain).
Collecting rainwater can be a bit tricky too, plus you should consider where the water is coming from. There is a difference if you collect water in a bucket in the middle of the yard (good) or if you collect water from a rain gutter that hasn’t been cleaned in ages and might even have a recently deceased animal hiding somewhere along the way (bad).
But all in all, if you live in a location where the quality of the rainwater should be good, then treating your plants with rainwater will be greatly appreciated by them.
Our thoughts: if you collect rainwater in limited quantities, use it for plants that don’t tolerate your tap water.
If you have a fish tank, you can use aquarium water to water your plants (freshwater only, naturally).
The water from the fish tank is great for watering your plants as it’s full of nutrients. It can even be used as a fertilizer to some extent.
Now, unless you have a ton of aquarium water at your disposal or only a plant or two, this type of water, although excellent, isn’t feasible as a main choice of water for your plants.
Filtered and softened water are not the same, this is very important.
Filtered water can easily be the best water for watering plants if tap water is your only option. There are filters available as pitchers or as faucet attachments.
These filters are designed to remove chlorine, fluoride, and heavy metals from your water making it better both for you and your plants.
Different filters provide different levels of filtering the water for unwanted particles. There are many different ones available in the market, so choose one you feel works best for you.
Filtered water is great to use. However, we still suggest letting the water sit for a couple of hours to reach room temperature before watering.
While bottled water is absolutely OK for the plants, assuming you go with regular bottled water (mineral, sparkling, or any flavored water is a no-go), it isn’t an optimal solution for the environment.
You will get the same results with filtered tap water (which a lot of time is the same as bottled water), so we would rather suggest you use filtered water for the sake of the environment.
What About Distilled Water?
Distilled water is wonderful for your plants, maybe even the best water for indoor plants, as this water is free of impurities. No impurities, no buildup.
Plants that are sensitive to tap water will thrive with distilled water.
You can purchase it in most stores or even make it at home. If you purchase the water, we suggest buying a large container and checking where you can get refills of distilled water locally. This is a more environmentally friendly solution than needing to buy the container over and over again.
You can also make distilled water at home. You can get a water distillery kit or go the DIY route by placing a small pot inside a larger one, pour water in the larger one. Close the pot with a glass lid, turning the lid upside down. Boil the water – as the water evaporates, it will collect on the lid (this is distilled water), and the water drops will slide towards the middle of the lid, where they will eventually drop into the smaller pot inside the bigger one.
You can also utilise the sun heat for the same process – although with a way slower rate.
Water From the Stream, Pond or a River
It could be OK, but you should get the water tested before using water from a stream to water your plants.
It could be perfectly fine or it could have a high content of heavy metals or pollutants.
Some streams that have been known as fountains of youth by generations have turned out to be quite toxic once tested. You never really know.
So What is the Best Water for Indoor Plants?
The final answer to this question isn’t completely straightforward.
If your tap water is fine, then this is the best water for watering most of your indoor plants. If you want to make it even better, you can add a water filter to your faucet to get filtered water.
While other options can be better in some cases, they do come with other setbacks. If your plants thrive on tap water or filtered tap water, this is the best option for you.
If you see some plants struggling with tap water still (getting burned foliage or stunted growth), use distilled water or other for those plants.
Whichever water you use, make sure the water is at average room temperature when you water your plants. Water that is too cold or too hot will harm your plant.