Herbs and Water Quality
Answered by: Inge Poot
Question from: No Name Given
Posted on: March 10, 2006

This may seem like an odd question, but what type of water is best for herbs?

I use purified water from my sink-mounted purifier (and occasionally distilled, but that is mainly for my Venus fly traps) for my indoor plants, but for my outdoor ones, doing that just isn’t practical. Is there any chance that the chemicals in municipal/tap water (the municipal water quality in my area is poor) can be absorbed by the herbs and ingested by humans? Can the chemicals in the water also perhaps affect the soil pH and thereby stunt plant growth or potency?

Herbs will of course take up chemicals that are in the water, but if the chemicals present in the water were so hazardous that drinking it yourself would be toxic the water would not be deemed fit for human consumption in the developed nations of the world.

Also, herbs are added in relatively small amounts to the foods they season and this dimishes the threat of using them even if the water is less than perfect. This does not apply to medicinal herbs. I would try to use purified water for them.

The real problem with municipal water supply is the pH. To keep the chlorine in solution the pH has to be kept around 8 -- which is high for many plants. For those needing an acid soil it is downright toxic. You would have to acidify it for those plants- use vinegar and figure out how much by trying it out drop by drop on a small pot of water -testing it with litmus paper -until it is as acid as the particular plant needs it and applying this result to a larger volume of water. Luckily most herbs can tolerate some alkalinity, especially if you use lots of humus in the soil mix.

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