If you plant them out you`ll almost certainly damage the growing root tip, and instead of a long single root on each plant you will get forked roots with 2 or 3 `prongs` on each. No good if you want the true parsnip appearance, but they taste just the same, and you`ll probably get almost the same weight of parsnip from each one - it`s just that they`re a bit of a b*gger to peel.