You have to put seedbag in any container, then open it from there (seedbag is in basket, for example) and then you can go evereywhere with opened seedbags window. You can use seeds that lay in seedbags from a distance. You can also put seeds into seedbag from a distance in the same way.
For expamle, cooking (using 20 seedbags full of seeds to craft none stop ), or harvesting (neighbour fields) to container at home.