The message
from Paul Luton contains these words:

As a first time parsnip grower I was pleased to get some decent looking
plants but reserved most for "after a frost". When I dig up the roots
now I find that they have deep splits from to to bottom and large brown
marks under the skin. Can anyone more experienced suggest what I have
done wrong ?
Thanks
Paul
--
CTC Right to Ride Rep. for Richmond upon Thames

Sounds like you have a few of problems. My parsnips always suffer from
some splitting, some rootfly and some canker - largely because I plant
them and let them get on with it.

You can mitigate your problems by using a canker resistant variety like
Gladiator F1 (widely available) and sow later in the season, during May.
Sowing later is said to reduce risk of canker. If you keep your
parsnips covered with fleece until late August you will also reduce risk
of root fly damage. Splitting is a water based problem and can be
avoided by regular, even watering. Don't let them dry out at any time.

If all this fails then simply do as I do and cut off the bad bits and
eat the good bits.

--
Compo