Bottled water, definitely a more expensive choice than tap water for your houseplants, might improve the condition of some of your ornamentals. Recommendations go both ways about distilled water, one of the bottled types, primarily because some of the chemicals removed may actually benefit your plants. Know about the moisture and light requirements for success with your container gardening. Choose your soil mix specifically for the type of plant going in the container. Orchids, cacti and Boston ferns have different soil, light and watering requirements. Whether bottled water or tap, water only when needed and be sure your containers have drainage holes.
Use bottled water for your houseplants if you are concerned the chemicals in your drinking water may not be good for them. Public water supply goes through processes that vary somewhat because it comes from different sources. The amount of chlorine and fluoride in tap water treated by municipal agencies is not enough to harm your plants, according to the University of California. There is not a consensus on this fact among the experts, however. Perhaps this is because of the differences in water, whether bottled or tap variety.
Ask your local agricultural agent or a local Master Gardener for help in determining whether your tap water is safe for the irrigation of your houseplants. Master Gardeners, volunteers trained by your local Cooperative Extension System office, are familiar with gardening in your area. Find the phone number under county government for Cooperative Extension for your local office. If your local garden center grows its own plants on site, it may have advice about the need for bottled water with your particular indoor gardening situation.
Water from softeners often contains sodium (salt) in amounts harmful to houseplants. Use your outside faucets to fill your watering cans unless they too connect to your softening system. Swimming pool water represents another threat to ornamentals because of the chlorine content. Even splashes from the pool can harm some sensitive leaves. Use room-temperature tap water for your indoor gardening needs. Let it sit for a day or two in your watering cans before using on your plants. This will not remove the fluoride, according to the Cooperative Extension System. Consider using bottled water if your leaf tips are turning yellow or brown or are dying even with these precautions.
The Food and Drug Administration (FDA) regulates bottled water in the United States. The Environmental Protection Agency (EPA) regulates tap water, considered the public's drinking water supply. Both maintain responsibility for the safety of bottled water. The water's source, bottling processes, storage and transportation come under the scrutiny of one (and in some instances both) of these agencies. These rules and regulations, whether from the FDA or the EPA, are in place to protect the public from consuming unsafe water. Some of these directives may also make bottled water a better choice for houseplants or ornamentals. Remember however, not all bottled water is the same, and some does come from public water supplies, so read the labels.
Rainwater is an option for watering nonedible plants. Systems that connect with your gutters can store this water for you. Be alert for mosquito development and algae formation. Well water is also an option, but have it checked to be certain it is not too alkaline. A filter, either on your kitchen tap or in a pitcher, might make your faucet water more acceptable to your houseplants. Other options you may try are used cooking water (might have nutrients from food) or water removed from an aquarium. Bottled water sometimes is a better option for your houseplants; tap water or water from other sources may work just as well for your container gardening. Ask questions and experiment to find the best choice for you.