Using microwave radiation is a common way to cook food. Microwaves, which are electromagnetic waves, can also affect growth rates in plants, especially on how seeds sprout and survive. Microwaves can also affect the size of plants after the seeds sprout. It is recommended, therefore, to use care when placing plants near microwave ovens.
Microwaves and Plant Soil
When soil is exposed to a prolonged dose of microwaves, plant growth within that soil is impeded, and germination rates go down, due to a diminished amount of nutrients in the irradiated soil. This results in plants that mature too rapidly and die before they reach full size.
When plant seeds are exposed directly to microwaves, they, like foods placed in an oven, begin to cook. While seeds don't cook as quickly as microwaved vegetables, they can lose viability from exposure to excess radiation. As a result, seeds will die or experience a compromised germination process.
Germination is the sprouting of a seed as it begins to grow into a plant. It's common for many seeds, when exposed to microwaves, to germinate at a much slower rate. Some seeds may germinate as they would under normal conditions, but the number of seeds that fail to produce embryos will increase during periods of prolonged microwave exposure.
Microwaved Water and Plant Growth
Unlike the detrimental affect direct microwave exposure can have on seeds and soil, the opposite affect is often experienced when plants are fed water that's been microwaved. According to JohnOhab.com, water that was microwaved before being fed to seeds can cause the seeds to germinate very quickly and plants to grow much taller than their traditionally-watered counterparts.