I noticed a few leaves that are browning on my rubber plant tree, and I have a theory that my water might be too harsh or there are too many minerals in the water because I noticed some white powder on the outside of my pot.

  1. Are there ways to verify that this is in fact true?
  2. Is this something that my plants would adjust to over time or are too many minerals generally bad for plants?

1 Answer 1


You can, of course, simply have a sample of your water tested. In most parts of the world, if you are on a public water supply, you can just look at their test results on file rather than having to pay for your own test of their water. If you are on your own well, you have to pay for the testing.

You can collect rainwater, which is essentially mineral-free, and try watering your plants with that instead of tapwater. You could also buy distilled water, but that's expensive for watering plants.

Generally what happens is we give up on growing things that don't thrive with the water (and other conditions) we can offer them, rather than them "adjusting" to things they don't tolerate. We "adjust" by growing things that will tolerate our conditions, unless we take steps to offer particular plants we want conditions they will tolerate, if they find our default conditions intolerable.

A bit of minerals on the outside of terra-cotta pots is fairly normal, and not a clear indicator that the water is intolerable, other than for bog plants that really would prefer rainwater or distilled water.

Rather than guessing at a cause ("perhaps it's my water") you might try asking about the actual problem, with pictures of the plant, showing close-ups of the browning leaves and a wider view of the situation the plant is in, as regards light, etc. Some other cause may be the real issue.

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