Water Quality and Ornamental Plants

Water quality and house plants

House Plants Not Blooming? It Could be Your Water

Poor water quality can affect your house plants. Chemicals such as chlorine and chloramine are routinely added to municipal drinking water throughout the U.S. These additives have been shown to inhibit blooming in flowering house plants and tropical greenhouse plants such as African violets (Saintpaulia), orchids, streptocarpus, bromeliads, poinsettias, amaryllis, geranium, Christmas cactus, rex begonia, Reiger begonia, and coleus, to name a few. Many bonsai and terrarium plants are adversely affected, as well, including foliage plants such as ferns, palms, ficus and aloe. Fortunately, my municipal water (New York City) has a neutral pH level and whatever additives it contains haven’t adversely affected my African violets or any other plants I’ve grown indoors, including orchids.

If your ornamental plants have stopped flowering it could be due to chemical additives or heavy mineral content found naturally in your tap water or local water source. If you use a water softener or conditioning system that can also affect bloom cycles. It’s a good idea to have your water tested if your plants aren’t growing or blooming well.

Flowering maple
Flowering maple grown indoors hydroponically using New York City tap water

Chlorine Causes Chlorosis in Tropical House Plants

Chlorine may not only inhibit bloom cycles but also can cause leaf burn and chlorosis, or yellowing of leaves, in soft-tissued plants like African violets and other gesneriads. Fortunately, chlorine is easily removed from water through dissipation (allow the water to stand uncovered for at least 24 hours before watering the plants) or through the use of a chemical dechlorinators which remove chlorine instantly and can be purchased from any aquarium or fish supply store.

Chloramine Affects Ornamental Plants

Chloramine is a combination of chlorine and ammonia that has recently replaced chlorine in many municipal water systems. Chloramine will not dissipate and can only be neutralized or removed through the use of water filtration systems. Since chloramine can also inhibit blooming in ornamentals you should check to see if your municipality uses the chemical additive. If so, allowing water to stand for 24 hours will not make any difference and therefore you might want to consider an inexpensive water filtration system for watering plants.

Water Filters for Watering Indoor Plants

Water purification systems are available in many different styles and price ranges, and conform to varying specifications. For indoor and greenhouse plants a basic kitchen under-counter unit designed to remove chlorine and chloramine will suffice.

    » If your plant collection is very small a refrigerator water filter may suffice. Moderate to larger house plant collections requiring several gallons of water at a time would be best served by a larger under-counter unit.

Reverse osmosis units (RO systems) are very popular among ornamental and tropical plant growers since they are designed to remove most municipal additives including chloramine. Carbon block filters and ultraviolet filtration systems are other options.

When comparison shopping for water filters be sure to check the specifications — included will be a list of exactly which chemicals, additives and organisms the unit is designed to remove as well as how long it takes for the unit to filter one gallon of water. Apartment dwellers might consider one of the many low-pressure water filtration units available since water pressure is often a problem in multi-unit buildings.

Many people use bottled water for watering their house plants. I haven’t found any difference between growing with bottled water and growing with my tap water, so I use tap water – and save the money to spend on more African violets. 🙂

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