Tap, rain or filtered water?
What's in your water, and which plants mind
Tap water suits most plants
Water that's safe to drink suits nearly all houseplants, and so do well water, rainwater and melted snow. Let it come to room temperature first, since very cold water can chill roots and spot some leaves.
If your plants look healthy on tap water, there's no need to change anything at all. Switch only if a plant shows a problem that points to the water.
Chlorine and fluoride
Chlorine doesn't harm most plants. If you'd rather remove it, fill an open container and let it stand for a day; the chlorine escapes and the water warms up.
A few plants, mainly dracaenas and spider plants, are sensitive to the fluoride in some tap water and can get brown tips or spots over time. If that happens, switch them to rainwater or distilled water. Damaged tips won't turn green again.
Skip softened water
Water from a salt-based water softener adds sodium to the pot, and over time it builds up and harms plants. Use a tap that bypasses the softener, such as an outdoor spigot, or use rainwater.
Hard water and white crust
Hard water carries minerals that stay behind as the pot dries, leaving a white crust on the soil or the pot. A little is harmless, but it adds to the salts in the pot.
Every 4 to 6 months, scrape off any crust and pour plenty of water through the pot, at least twice its volume, letting it all drain away.
Rain and distilled water
Rainwater is soft and has no added chemicals, so it's ideal for sensitive plants and for acid lovers. Collect it in clean buckets and use it at room temperature. If your tap water is hard, water onto the soil rather than over the leaves, which it can spot with chalky marks.
Distilled water carries no minerals at all. It's the best choice for very sensitive plants such as carnivorous plants, but regular plants rely on feeding for nutrients when you use it.
Related plant problems
Sources
- Missouri Botanical Garden: How to Water Indoor Plants
- Iowa State University Extension: How to Care for Houseplants
- RHS: How to grow houseplants
- University of Maryland Extension: Mineral and Fertilizer Salt Deposits on Indoor Plants
General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.