Hi, did always read this recommendation to let tap water stand, so that hopefully if chlorinated, it’d degassify.
I know not all waters might be chlorinated with chlorine but rather with other compounds, but just wondering if there are some bases to have standing tap water become healthier for watering plants?
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Increased CO2 dissolution, hence becoming slightly acidic?
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Degassified or treatment chemicals breaking down due to air and sunshine?
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Some other chemical breakdown, making it less sanitized (to the point that algae etc could grow if left long enough) hence less aggressive on roots?
Thanks for your help
Comments
It’s my understanding this no longer works in most places in the USA, due to the switch from chlorine gas to the compound chloramine for water treatment. Chloramine is stable and does not offgas.
For horticulture, tap water is fine if your plants do not require ultrapure water. For carnivorous plants and some high altitude cloud forest orchid species, a reverse osmosis filter for your water supply is needed.
>Increased CO2 dissolution, hence becoming slightly acidic?
Possibly, although it depends on whether your water is buffered by dissolved minerals. At any rate, the water will come to equilibrium with local CO2 concentrations/pH in the soil pretty fast when you water the plant, so I don’t think this will be too important.
>Some other chemical breakdown, making it less sanitized (to the point that algae etc could grow if left long enough) hence less aggressive on roots?
Besides chlorination, there’s not really anything added to water to sanitize it. Municiple water systems might add fluoride to help protect teeth, and whatever mix of natural minerals are in the water supply will come along too, but none of that is likely to cause problems for plants and it also won’t evaporate or break down in sunlight. Algae will grow as soon as you get rid of the chlorine (if you give it nutrients to grow on)
Broadly speaking I would say that there’s not really much reason to let water stand out, other than to lose chlorine.
>I know not all waters might be chlorinated with chlorine but rather with other compounds
real good tap water (like what i have) is not treated chemically at all
i let it stand for a while (or simply take rainwater) so it may precipitate some of its hardness (which is not all too effective)
>treatment chemicals breaking down due to air and sunshine?
yes, or simply reacting with organic matter – what it’s treated for in the first place
There are no common houseplants that are negatively impacted by the chemicals present in water that’s is cleared for consumption. Not by a long shot. There is no way that the level of chemicals in common used soil and fertiliser is affected by the extremely low concentrations of chemicals in tap water. The effect of cleaning your house with common cleaning products will add far and far more unwanted chemicals to your plants then tap water will ever do.
There are specific plants that require purified water. The chances that you own them are extremely slim. So don’t worry and use tap water.
Reminds me of my mother in law that keeps buying effing evian water for our chihuahua while we and the kids drink tap water.