Parsnips are fairly tricky to grow. The hardest part is getting them to germinate. Firstly, you need very fresh seeds (not left over seeds from last year) but even then germinating is likely to be patchy at best. Still, I put quite a lot of effort into getting my parsnips and carrots to germinate last spring time and I was rewarded with a fair crop of both.
Apparently, some of the starch in parsnips turns to sugar if the roots get frosted and this improves the flavour so I always wait until December before I start harvesting them. What I wasn't expecting was parsnips 18 inches long! And of course you can't tell how long they are when you start digging them out. You just dig and pull and dig and pull some more and wonder why the root isn't coming out. And the clay soil is troublesome. It sticks to everything, the root, the spade/fork, and my boots. Everytime I lift my foot I have to carry twice my boots weight in soil too. And all the time I try desperately not to damage the parsnip.
After a while the whole thing becomes like an archaeological dig, painstakingly removing the soil bit by bit and gradually excavating a trench around the precious object. Every now and then I stop and grab the thing with two gloved hands and heave, my hands slipping on the clay. It reminds me of the Enormous Turnip except there are no farm animals available to lend a hand and the mice are hibernating!
Still, eventually I got the thing out, although the hole I left behind looks like I used dynamite to do it! At home, I scrubbed it, peeled it and cut it into large chunks then par boiled it with some potatoes. Then both the potatoes and the parsnips were drained and tipped into preheated duck fat and roasted for an hour. Yummy and I can definitely taste the sugars.
I didn't mean to grow 18 inch parsnips - they are certainly difficult to get out of sticky clay soil. I mentioned this to some fellow kitchen gardeners the other day and asked the best way to get them out of the ground. They obviously didn't know the answer to this because instead they gave me advice on how to avoid the problem next year. They suggested preparing the ground with lots of sand so that they are easier to pull out. But I figure that this would just encourage the roots to grow even longer!