Hi'iaka's Healing Herb Garden

Does Microwaved Water Kill Plants?

We get a lot of information nowadays, thanks to the Internet and news sources such as CNN that send out the latest immediately after it happens. Some of it is true and some of it is not. Some of it is exaggerated and some of it is sent to promote the point of view of the person or company distributing it. It’s often difficult to discern which is solid news and which is not.

I’ve heard recently that if you boil water in a microwave oven, let it cool, and then water plants with it that they will die. I’ve decided to conduct an informal experiment to see whether there is any validity to this claim. But first, here’s some information I’ve discovered.

It’s on YouTube! A woman put sprigs of mint into identical glass jars and filled one with microwaved water and the other with water she boiled on the stove and let cool. Within five days, the mint in the microwaved water was struggling for life while the other was thriving, sending out roots and new foliage.

In another experiment, plants in potting soil were watered in the same way and after just nine days, the one watered with the microwaved water was all but dead.

How safe is food heated in a microwave?

Many studies have been conducted on the effects of microwave cooking. They show mixed results about the nutrient content of microwaved food.

A 2006 Cornell University study looked at the effects of microwave cooking on water-soluble vitamins in vegetables. Their conclusions? Spinach retained nearly all of its folate when cooked in a microwave, but lost 77 per cent when cooked on a stove. They also found that microwaved bacon has significantly lower levels of cancer-causing nitrosamines than conventionally cooked bacon.

Other studies have shown that microwaving destroys nutrients. I prefer to use my gas stove for most cooking.

What about microwave radiation?

Wikipedia reports that the radiation produced by microwave ovens is non-ionizing, which means it doesn’t have the cancer risks associated with ionizing radiation (X-rays, ultraviolet light). When rodent studies were conducted, constant exposure to microwave radiation did not cause cancer, even though they were exposed to higher radiation levels than humans are likely to encounter, even from leaking ovens.

The Food and Drug Administration, if you trust them, has conducted extensive testing of microwaves. Their research shows that the radiation, or radio frequency (RF), that microwave ovens emit does not pose any risks if the oven is in good working condition and it turns itself off when opened. Standing four feet or more from your operating oven significantly reduces your radiation exposure.

However, we don’t know much about what happens to people exposed to low levels of microwaves. The FDA Web site says, “Controlled, long-term studies involving large numbers of people have not been conducted to assess the impact of low-level microwave energy on humans…. There have been allegations of radiation injury from microwave ovens, but none as a direct result of microwave exposure. The injuries known to FDA have been injuries that could have happened with any oven or cooking surface. For example, many people have been burned by the hot food, splattering grease, or steam from food cooked in a microwave oven.”

Safe microwave tips

Pierce cooking pouches and foods with tight skins, like tomatoes and hot dogs.
Never cook eggs in the shell.
Remove lids or caps from containers, and cover with microwaveable plastic wrap (don’t let it touch food) or waxed paper.
Never turn on an empty microwave.
Keep the inside, the door and the seal clean.
Never operate the oven when something is caught in the door.
Remove metal twist ties from bags.
Never use brown paper bags because they can catch fire.
If you microwave Chinese take-out boxes, remove the metal wire.

For more information on microwave oven radiation, contact the Consumer Staff of the Division of Small Manufacturers, International and Consumer Assistance (DSMICA) by e-mail at DSMICA@cdrh.fda.gov, or go to fda.gov/cdrh/comment4.html.

Is this a hoax?

When I start my experiment I will use young tomato plants in potting soil. When they are about two inches tall, I will begin the experiment and photograph and record my observations over whatever period of time it takes to notice any difference. I will use two plants for each type of water and will use young, tender, susceptible plants instead of older ones that might be hardier. It would be interesting to try older plants too: a bromeliad might be a good choice for this. I challenge our readers to conduct your own experiments and send me your observations. I’ll write all about it in a future column.

On the Web

goaskalice.columbia.edu/0700.html
fda.gov/cdrh/consumer/microwave.html#5
hps.org/hpspublications/articles/microwaveoven.html
youtube.com/watch?v=_rlJL-2R7TA&feature=related
en.wikipedia.org/wiki/Microwave_oven#Dangers
museumofhoaxes.com/hoax/weblog/comments/4108/
fda.gov/cdrh/comment4.html