Many individuals consider reusing dehumidifier water for their plants. Understanding its nature is a first step in determining its potential benefits and drawbacks for plant care.
What is Dehumidifier Water?
Dehumidifiers draw moist air over a cooled coil, causing water vapor to condense into liquid. This process removes humidity, collecting water in a reservoir. The collected water is essentially distilled, with very low mineral content compared to tap water. This low mineral profile results from the evaporation and condensation cycle, leaving behind dissolved salts and minerals.
Despite its distilled nature, dehumidifier water is not entirely pure or sterile. As air passes through the unit, it can pick up impurities from internal components. These may include dust, mold spores, bacteria, or, in older units, trace metallic particles like copper or aluminum.
Understanding these potential contaminants is important before using the water for plant irrigation. Water quality varies significantly based on the dehumidifier’s age, maintenance, and air cleanliness. Assuming the water is perfectly pure can be misleading.
Advantages and Disadvantages for Plants
A primary advantage of dehumidifier water is its low mineral content, resembling rainwater. This benefits plants sensitive to mineral salts in tap water. Carnivorous plants, orchids, and ferns thrive with minimal dissolved solids and can suffer from mineral buildup, leaf tip burn, or stunted growth from hard water. Dehumidifier water helps prevent mineral salt accumulation in soil, which can impede nutrient uptake.
However, the absence of minerals advantageous for some plants is a disadvantage for others. Tap water provides beneficial micronutrients like calcium and magnesium. Relying solely on dehumidifier water might lead to deficiencies. Contaminants like mold spores, bacteria, or trace metals from the dehumidifier’s coils can also pose a risk to plant health.
These impurities, even in small concentrations, could introduce pathogens to the soil or harm sensitive root systems. The water may appear clear but is not sterile and can harbor microorganisms. While suitable for specific, salt-sensitive species, general application requires careful consideration of its purity and the plants’ nutritional needs.
Safe Use and Best Practices
Before using dehumidifier water, inspect it for clarity and odor. Do not use water that appears cloudy, discolored, or has an unusual smell, as this indicates contaminants or microbial growth. Pouring it through a coffee filter or fine mesh can remove larger particulate matter. Allowing it to sit uncovered for at least 24 hours can also dissipate volatile organic compounds or chlorine if the dehumidifier was recently cleaned.
To mitigate nutrient deficiencies for plants benefiting from minerals, consider mixing dehumidifier water with tap water or collected rainwater. A 50/50 blend is a common approach, providing beneficial minerals while reducing the overall mineral load. Avoid using water from a visibly moldy dehumidifier or one cleaned with harsh, chemical-based cleaners, as residues could harm plants.
For plants highly sensitive to mineral salts, such as carnivorous species or epiphytic orchids, undiluted dehumidifier water might be appropriate. For most common houseplants, a diluted mixture is safer and more beneficial. When introducing it, water a single plant and observe its reaction over several weeks. Signs of stress, like yellowing leaves or stunted growth, suggest the water may not be suitable or needs further purification or dilution.