Photo: What water to use — Luis Tosta · CC0.
Water
What water to use
MYTH
Never use water straight from the tap — let it stand first.
FACT
Water that's safe to drink suits nearly every houseplant, as long as it isn't cold. Letting it stand gets rid of chlorine, but not fluoride.
What actually matters
- Room temperatureCold water can harm tropical plants, especially in winter. Fill the can ahead of time and let it warm up.
- Not from a softenerA water softener is an anti-limescale unit with a tank you fill with salt. Softened water carries salt into the soil, and it slowly kills plants. Use a tap that bypasses the softener.
- Stand it for chlorineA day in an open container and the chlorine is gone. Most plants don't mind chlorine, but it helps the sensitive ones.
- Sensitive plants: rainwaterDracaena, spider plant, calathea, prayer plant and ti plant can get brown leaf tips from chlorine and fluoride. Standing doesn't remove fluoride, so give them rainwater or distilled water if you can.
- Carnivorous plants and orchidsWater carnivorous plants (a Venus flytrap, say) and orchids with rainwater or distilled water. Hard tap water doesn't suit them.
Sources: Iowa State Extension, Missouri Botanical Garden, RHS, UNH Extension, Arizona Extension, American Orchid Society.