Good to know although I never had a reaction to parsnip.
Last year I had sown parsnip in my poly tunnel bed. All speedily came out and by July I was harvesting giant parsnips. I really had to dig them out with my hands till about half way down the lenght of the parsnip before trying to rock them out! Also in the garden they were a success although not so large as those in the poly tunnel.
This year it is however another story. Because of the warm weather we had in May and June. the parsnip did not want to germinate in garden as well as in poly tunnel. I tried 3 times and finally gave up. In July a few of them finally germinated, but they remained small and are still small. Happily enough I still have some parsnip in the deep freeze from last year!