not any more. the only space you will need in between the rows in your home vegetable garden should be the size it takes you to walk between them.
if you need a twelve inch row then the next plant of the same or even a different variety should be no closer than twelve inches correct? so make sure you space out your vegetables properly. if you need twelve, make it twelve, not sixteen or twenty. if you are doing that you are wasting space, and creating room for weeds to grow. invest in a ruler or tape measure if you have to, but make sure you space those seeds out 