Parsnip?

Parsnip growing can be quite annoying. You normally finish up with big gaps and the ones that do germinate take ages to do it.

I know what you mean. I think the minimum germination standard for parsnip seeds is very low. In 1975 it was 25%. I can't find it in the 2002 regulations list:
http://www.legislation.gov.uk/uksi/2002/...ule/4/made        the second table on this page but other vegetable % are unchanged in 2002 from 1975. I should think it is still the same today.

Then there is this article from 2007:  https://www.telegraph.co.uk/news/uknews/...-dead.html
about seeds in general. I doubt anything has changed.

I was pleasantly surprised this year that my 2 rows of parsnips have germinated really well with just a few gaps in one row.