I filled the rolls with a general purpose compost, packing them, standing up (the rolls not me) in seeds trays and kept them indoors till I saw a few germinate, then I put them, still stacked in trays outdoors. About a month ago I planted the rolls into one of the roots beds, though some had still to show signs of germinating.
By this weekend most have happy little parsnip seedlings flourishing. In the few which don't I have just sown some fresh seed.
I am trying two varieties new to me (I usually sow Tender and True): Cobham Improved Marrow and Gladiator F1. All the Gladiator germinated, it was the Cobham where I had to fill gaps. For more information on them see: Cobham and Gladiator.
Not that I'm wishing my life away, but can't wait till next winter for roast parsnips!