After we’ve had a few good frosts, you should find that the flavour of homegrown parsnips is at its best, as the cold spell will have sweetened them up. If the ground is soft enough to pull them up, then it’s a great time to harvest.
How do parsnips grow?
Although gardeners treat parsnips as an annual plant, they are in fact biennials. The seeds are normally sown in spring, the roots swell in autumn and the foliage dies down over winter, at which point they are usually harvested. If left in the ground beyond winter, the plants will sprout again in early spring, producing more leaves as they go to flower. Once they re-sprout, the roots develop a tough, woody core and become fairly inedible.
Why harvest parsnips after frost?
Most gardeners like to harvest parsnips after the leaves die down in late autumn, and after the first few frosts. The reason behind this is that the roots become sweeter after standing in the cold soil for two or three weeks as starch is turned to sugar. (A single frost won’t make much difference – it needs to be frosty for a week or so for the sweetness to develop.)
Why are my parsnips damaged?
In normal UK conditions, this parsnip journey is fairly standard and makes it easy for the grower to harvest the roots after frosts but before spring sprouting. However, it is a little more problematic in recent years, especially in those parts of the country that are milder and wetter, which is often the case for us here in Cornwall.
Because the autumn and early winter temperatures are milder, frosts come later in mid to late winter. This can mean that the roots are often standing in wet soil during November and December, and so are more prone to developing disease like canker where the shoulders of the roots start to turn orange/brown before rotting.
What if I don’t get any hard frosts? When should I harvest?
We’d advise harvesting as soon as the foliage dies down if it looks to be a mild winter in your area in order to harvest healthy roots before they turn woody.
Can I sweeten parsnips up in the freezer?
There is plenty of advice out there saying that you can freeze parsnips in the freezer to mimic frost and sweeten them up that way. Our Rocket Gardener tried this last year, and reported that the flavour was unchanged, although she only froze the roots overnight. You could try, perhaps freezing for longer would make a difference – and let us know how you get on if you do try it!
How can I store parsnips?
Once harvested, you can store parsnips in a clamp of sand or barely moist soil, in a cold, dry place (like a watertight garden shed) for 3-4 months. Alternatively, keep them in the fridge for 2-3 weeks, or parboil and freeze.