Wednesday, January 7, 2009

The first experiment (from 2007)

A couple of years ago I became intrigued by the discussion about the harmful health effects of microwaved food. I kept hearing stories of tests wherein plants that were fed water that was microwaved to boiling temperature and then cooled did not survive.

It's easy to find references to this on the web, so I shall keep my little contribution to this discussion very brief.

In July of 2007 I was visiting a local farmers market and noticed two very similar potted flowers. I decided then to run a little experiment of my own. I brought them home and set them on the balcony, side by side. On a shelf inside I kept two identical containers. One I filled with tap water that had been boiled in an electric kettle and then cooled. The other I filled with tap water that had been microwaved to boiling point and then cooled.

One plant I labeled "E.K. Water" - that is, Electric Kettle Water. The other I labeled "M.W. Water." Each plant was watered at the same time, until the water started to flow from the bottom of the pot. They were given no other food.

Here is a photograph of the two plants the day after I brought them home. In all these photographs the plant that was fed microwaved water is on the right.

That photograph was taken July 13th, 2007. On July 22nd I repotted the plants, and photographed them the next day. One's immediate impression might be that the plant on the right, the one fed microwaved water, was not doing as well. This is because the new buds have not opened - on a closer look you will see that the foliage looks healthy. Here is the photograph taken on July 23rd, 2007.

The experiment continued until August 15th, 2007. Only a month. At that time we went on vacation. The person who was to keep the plants watered did not do a very good job, and both were bone dry when we returned. However you can see from the next photograph that both plants looked vibrant the day before we left.

Granted, this is not much of an experiment. It does show, though, that feeding a plant microwaved water for a month will not kill it.


Jennifer said...

How often did you microwave the water? The microwave oven may have an effect on water that wears off over time so if water was sitting for days in a container after being microwaved, it might be identical to tap water at that point.
I did an experiment with wheat grass seeds in identical containers and identical soil source. I used DAILY-microwaved tap water (cooled to room temp of course) to water one and the other was just tap (not heated at all). The seeds watered with the microwaved water had about a 50% lower germination rate. But once the seeds sprouted the plants grew identically to the plain tap watered plants. (All the water used to water the plants was stored in glass jars.)

Anonymous said...

I think its really great you took the time to do these experiments and share. Thanks!

Cristian Ronald said...

I'm doing a research about "does microwaved water affect the growth of plants?" And I don't have any clue about if microwaved water killing plants. Some websites say that it doesn't some say that they do. I'm freaked out.��

Robert W. Harwood said...

My own experiments, Mr. Ronald, were too brief to be conclusive. I did find, though, that much of the notion of the evils of microwave cooking derived from a young girl's school science experiment, which her proud grandfather posted on the web. In that experiment, the plants that were fed microwaved water died.

In my experiments - two of them - I could detect no difference, and the plants that were given microwaved water thrived. Through both of my experiments, the sizes of the pots and the amounts and temperatures of water delivered were identical, so I was careful to avoid variables. My conclusions were that, during the length of the experiments, there was no discernible difference in the growth of tomato plants served tap water, cooled boiled water, or cooled microwaved water.