Microwaved water vs. kettle boiled water for plants – Part 1: The Concept


I recently became aware of a web page that purports to show the difference between watering plants with water that has been heated in a microwave and water boiled by more traditional means.  Supposedly, the plant that was fed the microwaved water died while the other did not.  You can see that page here.

Naturally, I went to Snopes to see if they’d looked into it.  They had and, as I expected, they considered the claim to be false.  You can see their page about it here.

Why leave good enough alone, though?  I’m going to try the experiment myself.

Unfortunately, my experiment will be open to some criticism because of the small size and the fact that I don’t have the resources to make it a double-blind test.  Nevertheless, I think the results should be worth some consideration — not to mention that mine is triple the size of the original one.  I should also declare my bias: I strongly suspect that the outcome of the “test” on the original page is the result of either incompetence or deliberate sabotage of the plant receiving the microwaved water.  I think that it preys on the anti-science and anti-technology paranoia that some people harbour.

Here’s what I’m going to do:

According to the eHow.com page on how to boil water in the microwave, if you want to do a litre of water (four cups), you should put it on “high” for 10 minutes.  Just to make sure, I’m going to do 20 minutes.  If heating in the microwave alters the “structure” and “energy” of water, as suggested in the original web page, I want to make sure I alter it plenty! 😉

The non-microwaved water will be brought to boiling in an electric kettle.  The water will be stored in identical, clearly labelled, well-washed 1 litre reclosable beer bottles.  Each time the bottles are refilled, they will be sealed and allowed to stand overnight to be sure the water cools to room temperature before being used to water the plants.

The water will be used to water six potted plants from when the seeds are sown*  and onward, three for each bottle of water.  All seeds will come from the same packet.  I’ll sow four or five seeds in each pot and cull all but the strongest seedling in each.

The plants will be kept a south-east facing window sill, rotated regularly to promote straight growth and equality of growing conditions.  A “grow light”, which is already in place for another little project I’m doing, will be suspended above them.  It’s on a timer and is on from 6 am to 6 pm.

I’ll post again when I have the pots filled and seeded, and I’ll include photos of that then.  For now, here are photos of the equipment I’ll be using for the water:

*Regular chlorinated municipal tapwater will be used for the initial soaking of the growth medium in the pots.  After that, only the prepared water will be used for watering.

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