Horseradish root that I can plant?

I would like to plant horseradish root this year in my north Toronto garden. Can I buy the root in a grocery store and plant it or do I need to buy it elsewhere? Any idea which stores sell the…

horseradish (herb) plant

How do I know when to check that the roots are ready to get the horseradish?. I have a two-year plant with long leaves and I have not checked yet the roots. Once I took some, can I replant it?…