Posted: 06/01/2015 at 18:36
Could be any of the above, with too rich a soil being high on my list of suspects. Parsnips definitely need to be sown in-situ and will deform like those in the photo if transplanted from seed trays etc., as Mark says. I would never buy root crops in plug form for that reason.
When I grow them in raised beds, it's in a 50/50 mixture of sharp sand and multi-purpose compost with fish, blood and bone fertiliser tickled into the surface a few weeks after they have started growing strongly. That method has never failed me yet (perfect for carrots, too.)