Silver is anti-bacterial, anti-fungal and anti-viral. Romans used to put silver coins in their wine to help preserve it. Putting silver coins in wells to purify water is another example. Also, the term "born with a silver spoon in his mouth" was because the rich people didn't get the plague in part due to silverware made of actual silver. It's been used for thousands of years as a medicine and used to purify water aboard the space station so they didn't risk bringing chlorine. There are TONS of uses for colloidal silver, in addition to making feminized seeds!