Does Microwaved Water Actually Kill Plants? | MythBusters

Microwaved Water and Plants: A Toxic Myth?

The internet is rife with claims, and one particularly persistent myth suggests that water boiled in a microwave becomes toxic to plants. Viral images purport to show plants watered with microwaved water withering and dying, while those given purified water thrive. The MythBusters team, ever eager to debunk or confirm such claims, set out to investigate. Their experiment involved eight romaine lettuce seedlings, divided into four groups. One group received water boiled in a microwave, another received water boiled on a stove, a third was given regular tap water, and a final control group received no water at all. Crucially, all boiled water was allowed to cool to room temperature before being administered to the plants, as pouring boiling water directly onto any living organism would, predictably, kill it. The plants were housed in a custom-built rig, ensuring consistent watering schedules and exposure to grow lights for 16 hours a day. After two weeks of observation, the results were clear: the plants watered with microwaved water were not only healthy but were actually outgrowing all the other groups. This definitively busted the myth, highlighting that the method of boiling water (microwave vs. stovetop) has no discernible negative effect on plant growth once the water has returned to a suitable temperature. The underlying scientific principle is that microwaves heat water molecules through vibration, converting this vibration into thermal energy. No radiation is imparted to the water during this process, making microwaved water chemically identical to stovetop-boiled water once cooled.