Parsnips

For me, parsnips are a great treat of winter and I actually look forward to the first hard frost, which changes the flavour of parsnips from rather bland to rich and sweet.

Like many winter vegetables, you have to plan ahead if you want to grow parsnips. I’ve just sown my first parsnip seeds (variety “Tender and True”) on the allotment and will continue to sow until mid or late April, though earlier sowings usually do best on our sandy ground, as there is more water in the soil at this time of year.

The seedlings are slow to germinate and I usually intersow with radishes, to mark the rows and give me an early crop for salads. Radishes grow quickly and are out of the ground within a couple of months, giving the parsnip seedlings room to grow. The parsnips then grow throughout the summer and early autumn until it’s time to eat them. Last year I had to wait until late November because it was such a mild autumn. They can be left in the ground until needed in the kitchen, until late March or early April. On a very cold day they may need to be chipped out of frozen soil, but they will come to no harm.

The cultivated parsnip, Pastinaca sativa, is a selected form of the Wild Parsnip, a member of the carrot family, the Apiaceae. It is a biennial which grows in much of the British Isles, though it is commonest in England (see distribution map). I associate it with Norfolk’s Breckland, where its umbels of yellow flowers brighten summer afternoon walks. The roots of Wild Parsnip are edible but they won’t win any prizes at a produce show as they’re very spindly and you’d find it hard to make much of a meal from them. In his Hedgerows book (River Cottage Handbook No. 7, Bloomsbury 2009), John Wright suggests making them into parsnip crisps.

There are many recipes for parsnips and even a website called www.parsniprecipes.co.uk, which has recipes and loads of information on this fine vegetable. Other recipes are listed on websites such as BBC Good Food. Parsnips combine well with spices and there are many recipes for curried parsnip soups, such as this one from Gourmet Britain. I love roasting potatoes and parsnips in the oven in goose fat (cut into chunks, parboil for five minutes then cook at Gas Mark 6 for 1 hour), or you can use olive oil if you prefer.

Like many plants, parsnips were used as a medicine as well and the roots were used to treat swollen testicles and tooth and stomach aches. Nutitionally, they are a good source of potassium and fibre. They were often used as animal fodder.

Both wild and cultivated parsnips contain furanocoumarins (psoralens), compounds which cause phytophotodermatitis, a skin rash that occurs in the presence of sunlight. In the UK Giant Hogweed, Heracleum mantegazzianum, is well known for causing blistering of the skin when it is cut on a sunny day but a splash of parsnip sap on the skin can have the same effect.

I have first hand experience of phytophotodermatitis from both wild and cultivated parsnips.

When we took on our allotment we had lots of self sown (cultivated) parsnip plants growing amongst the grass. One sunny day Vanna was cutting the grass with hand shears and knelt on a cut parsnip leaf. She soon developed a blistered, burnt piece of skin on her knee which healed to a brown patch of skin that persisted for several months.

In the 1990s I ran a conservation group, Norwich Environmental Weekenders, which did work on Norfolk Wildlife Trust nature reserves. One task (which I didn’t attend) was on a hot sunny day and involved cutting back Wild Parsnip from Ringstead Downs, near Hunstanton in north-west Norfolk. One girl turned up on the following task, a week later, with a blister on the end of her nose where she’d been splashed with the sap.

In the United States, the Wild Parsnip is an unwanted alien species that is spreading fast and has to controlled.  (See Alien Profile: Wild Parsnip and Poison Parsnip.)

Furanocoumarins act as mutagens, damaging DNA. A study in 1981 found significant concentrations in parsnip roots that weren’t destroyed by cooking, which is why one of my Genetics lecturers at university wouldn’t eat parsnips. In the paper the researchers said “psoralen-containing food plants may present some toxicological risk to man” but qualified this with the statement “People have been eating parsnips for years with no ill effects we know about. The potential is there but I think it’s rather small.”

Celery (Apium graveolens) also contains furanocoumarins and can cause a rash when handled in strong sunlight. I even found an intriguing paper that describes how a woman who ate a lot of celery and went to a sun tanning parlour very soon afterwards suffered “a severe, generalized phototoxic reaction”, presumably phytophotodermatitis (Arch Dermatol. 1990; 126(10): 1334-1336.)

I will continue to eat parsnips, and as I only eat them in winter when sunlight levels are low, this should diminish any harmful effects. Furanocoumarins are also broken down quite quickly (reference). However, I will avoid eating parsnips that have been stored for a long time, especially any that have gone mouldy, as this can lead to roots with high levels of psoralens (See, for example, Effects of storage conditions on furocoumarin levels in intact, chopped, or homogenized parsnips. J Agric Food Chem. 2002 Apr 24; 50(9): 2565-70.)

My other favourite parsnip related fact is that the surname of Boris Pasternak, the Russian author of “Dr. Zhivago”, means “Parsnip”.