How will tap water, mineral water, and seltzer water affect the germination and the growth of radish seeds? My hypothesis is that radish seeds will best germinate and grow in mineral water. Mineral water may have fewer contaminants that can hurt the germination of the seeds and perhaps this absence will help the growth of the plants. I also think that tap water will have a detrimental effect on both the germination and the growth of the plants. I am not sure what effect seltzer water will have on the radish seeds. It might be possible that the aeration will hasten growth (C02 makes water pH acidic.) On the other hand, this acidity level of the seltzer water might be detrimental.