Pastinaca sativa, family Apiaceae
Many vegetables are in the same family as parsnips. In this course we have carrots, celery, celeriac and fennel, and others include parsley, coriander, dill and cumin. All grow umbel shaped flowers in their second summer, hence the colloquial family name of umbellifers.
Parsnips are native to Asia and Europe, and were much appreciated by the Romans. They are nothing like as popular as carrots and deserve to be better known, partly because they are easy to grow and are a substantial harvest for winter.
- The part we eat of both parsnips and carrots is the taproot.
- They are the two vegetables that are best sown direct rather than transplanted. Transplants usually suffer damage to the taproot, resulting in a smaller harvest with fanged roots.
Wild parsnips are common in hedgerows of temperate regions, and they carry tall stems with pretty white flowers, every year in late spring. All parsnips are biennial plants that we grow as annuals – see ‘Varieties’ below.
Harvest period
- Days from seed to first harvest: 180, to last harvest: 390
- Best climate is moist, warm summers, not too hot and dry, with cool winters.
Why grow them
Parsnips have about an 80% water content, which may sound a lot but is very much at the low end for vegetables. Carrots are 86–95% water, depending on the variety and when harvested.
About 5% of parsnip roots is sugar of different kinds, which helps them to resist damage by freezing. In cold weather the sugars convert from starch to sucrose, hence the advice to eat parsnips after a frost, for more sweetness.
- They were used as a sweetener in parts of Europe, before the arrival of cane sugar in the 18th century.
The sweetness is also enhanced by roasting, which, in the UK at least, is a traditional way to eat parsnips and makes them super tasty. They are also delicious grated raw in salads, with some lemon juice.
The photo above right is of harvests in 2016 from my Three Strip Trial – I am unsure why Strip 3 was lower in that instance.
Pattern of growth
One difference to carrots is that parsnips continue to swell all through the growing season, from one early sowing. In contrast, carrots start to lose quality about four months from sowing, becoming less tender and sometimes splitting.
Through autumn, parsnip leaves start to yellow and then go brown, leaving what was a bed full of abundant growth looking suddenly barren. Our food, the parsnip taproots, survive winter in a dormant state. Then, as soon as there is warmth in late winter or early spring, they sprout again.
- New growth in the second spring is not contributing to any more growth of the parsnip tap root.
- In contrast, it is taking goodness from that root, because parsnips are storage organs that power new growth in early spring to make flowers and eventually seeds.
Growing a flower stem makes the taproot woody and inedible. Therefore it’s best to harvest parsnips by late winter before too much growth has happened. From early spring, sugars in the roots are used by new growth, while the texture becomes fibrous.
Suitable for containers/shade?
Parsnips will grow in shade, and you could grow them in a container as well, although they would occupy the container for a whole year.
You need a pot of 30 cm/12 in depth, or a little more, in order to have a worthwhile harvest.
Follow with:
Parsnip harvests finish too late for any new sowings until spring.
Any vegetables can follow them, preferably of a different family. I reckon leaving at least a year between growing carrots and parsnips in the same ground, especially parsnips, because they occupy a bed for all or most of the growing season