Just a warning -- The only problem I see with this is that you could be introducing diseases into your garden that you didn't have before. I've actually had this happen to me.
I only used either certified seed stock or my own homegrown potatoes for starting on my farm. But a few years ago the farm hosted our area's community garden. One of the
volunteer gardeners brought store brought potatoes from home and planted them into the garden, without my knowledge. Regretfully those potatoes introduced early blight, a problem that didn't exist in my area before. As a result, growing potatoes in my main garden is now difficult. I have had to resort to using raised containers filled with virgin soil for growing potatoes and tomatoes.