How to grow parsnips

The hardy parsnip is a staple of the allotment in winter. Used in soups, stews and casseroles as well as roasted in the classic Sunday lunch this versatile root vegetable was once used as a sweetener in cakes and desserts.

Although notoriously slow and sometimes unreliable in germination, once started they need little care.

Sow parsnips

Seed packets will usually suggest sowing from February until May but parsnip seeds need a temperature of around 12C to germinate so it is best to wait until the soil warms up. On my allotment in Wiltshire I usually sow in April. For early sowing, or in cooler areas use clotches to warm the soil if you have them. Even in ideal conditions germination can be unreliable so be prepared to make two sowings or more if necessary.

It is advisable to use new seeds each season as parsnip seeds viability can be quite short.

Choose a sunny spot on ground that has not been recently manured or composted. Sow seeds thinly in a pre-watered drill about 1cm deep. Cover and water again. Allow 30cms between rows. Keep the soil moist.

Germination may be slow, normally taking two to four weeks. I sow a second batch after two weeks if there is no sign of germination of my first attempt.

Thin to about 10cms between seedlings if necessary. Keep the soil moist and weed-free as the seedlings develop. If temperatures are forecast to drop cover with fleece or clotches.

It is worth noting that parsnips do not transplant well so starting them in pots under cover is unlikely to be successful. Once germinated they quickly form a long tap root, if this is disturbed growth will be stunted and the root is likely to fork. They are a vegetable that is best harvested in autumn and through the winter so there is little benefit in trying to get them off to an early start. It is best to sow seeds where they are to grow.

It is said that parsnips do not thrive in clay soils but I have had good success growing on no-dig beds on my heavy clay. Clay takes a long time to warm so delay sowing to allow for this.

Grow parsnips

Once established parsnips need very little care. Keep the bed weed-free as they develop but as they grow the foliage should start to supress the weeds. They are reasonably drought tolerant but in particularly dry weather an occasional thorough watering will prevent the roots from splitting.

Harvest parsnips

Parsnips can be harvested when the foliage begins to die back, usually from early autumn, but the sweet flavour is enhanced by a frost. They can be left in the ground all through the winter but also freeze well should you prefer to harvest and store the crop.

Don’t forget to mark your rows so that it is easier to find the crop when the foliage has gone.

It is best to harvest all your parsnips before spring as they will start to develop tough cores if they are left too long.

Storing parsnips

Parsnips freeze very well.

Parsnip problems

Parsnips are generally problem free but as part of the carrot family they are vulnerable to carrot fly damage. Cover with a fine mesh to avoid the problem. Carrot fly damage on parsnips is usually quite superficial. It can usually be removed when peeling, leaving a perfectly usable root.

They can also be affected by canker which causes scab-like brown damage on the skin. Choose canker resistant varieties to avoid this. Whilst a little unsightly canker is not dangerous. The damage can be trimmed off and the roots will still be perfectly safe to eat.

Other thoughts on parsnips…

Although we grow and harvest parsnips in one growing season they are a biennial plant, completing their full life-cycle in two years. If left in the ground they will start to grow again in spring and will go to seed in the autumn. If you want to save seeds you will need to wait until the second year to do so.

They have an attractive seed-head similar to cow-parsley which is part of the same family of plants. It produces hundreds of seeds that are easy to save once the plant dies off and the seeds dry. Note that if your parsnips were grown from F1 seeds they may not produce roots with the same characteristics as the parent.

Once the second year’s growth begins, the roots are likely to have a tough core so might be unpleasant to eat.