Delicious roasted or added to hearty winter stews, parsnips are easy to grow, need little maintenance and can be left in the ground until you’re ready to eat them. Sow in spring and you’ll have sweet, tasty, home-grown parsnips by autumn – and for your Christmas dinner too.
A traditional and popular autumn and winter crop, parsnips are undemanding, low maintenance and a must for any veg grower, from beginners to experts. Although slow growing, these deliciously sweet, earthy roots are well worth the wait.
They should be sown direct into their growing position in spring, ideally in light, free-draining soil. Few pests trouble them, apart from carrot fly, which can be deterred with insect-proof mesh. Seed germination is notoriously slow and erratic, so only sow once the soil is warming up, use fresh seed every year, sow plenty and be patient.
Parsnips need little ongoing care, apart from weeding when young and watering in dry spells. The roots are ready to harvest from autumn onwards, although it’s best to delay until after the first hard frost for the sweetest flavour. They’re very hardy and can be left in the ground right through winter, to be dug up whenever needed, for a tasty home-grown treat.
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There are several varieties to choose from, varying mainly in size and shape. Most form long, tapering roots, although a few are shorter and more bulbous, which is preferable if you have heavy, shallow or stony soil. Roots range in colour from cream to pure white, although all have a similar flavour.
It’s worth choosing a variety that is canker-resistant and has an RHS Award of Garden Merit (AGM), which means it should grow well and crop reliably – see our list of AGM fruit and veg.
What and where to buy
Parsnip seeds are widely available in garden centres and from online suppliers. Only buy enough for one season though, as old seeds germinate poorly, so to avoid disappointment it’s best to buy fresh ones every spring.
Preparing the Ground
Parsnips prefer an open, sunny site, with fertile, light soil that drains readily. Soil that has been improved with well-rotted manure or garden compost the previous season is ideal.
To help ensure long straight roots that don’t fork, remove as many stones as possible and loosen heavy clay or compacted soil, but don’t add any organic matter before sowing.
If the spring weather is cold and wet, cover the soil with a cloche or plastic sheeting a couple of weeks before sowing, to dry it out and warm it, as parsnip seeds don’t germinate well in cold, damp ground.
Parsnips have a reputation for being tricky to germinate, but if you wait until the soil has warmed up in mid-spring, use fresh seeds and sow plenty, you should have good results. Simply follow our tips.
Sowing indoors in not recommended, as parsnips form a tap root that doesn’t transplant well.
Although it’s sometimes recommended to start sowing in February, in all but very mild locations this will usually be too cold for reliable germination – wait until temperatures are around 12°C (54°F). Sowings made in March and April, and even early May, tend to do much better.
After preparing the ground (see above), make a shallow drill, 1cm (½in) deep, then water along the base if the soil is dry. Scatter the seeds thinly along the drill, or sow three at 15cm (6in) intervals – germination can be unreliable, so it’s best to sow more than you need.
Cover the seeds with soil and water again if no rain is forecast. Label the row and mark it with sticks at each end. Space additional rows 30cm (1ft) apart. Cover with cloches or fleece until the seedlings have developed two true leaves.
Parsnip seeds are renowned for being slow to germinate – seedlings can take from 14 to 30 days to appear, depending on conditions. Keep watering and weeding regularly, both before and after germination.
Sow a fast-growing crop such as radishes between your parsnips to maximise your growing opportunities. The radishes will be harvested long before the slow-growing parsnips need the space.
Thinning out seedlings
When the seedlings are about 2.5cm (1in) high, thin out to leave one every 15cm (6in), removing the smaller, weaker ones.
Keep the soil weed free, especially when the plants are young, so they don’t have to compete for water, nutrients or light. Hand-weed rather than hoeing close to the plants, to avoid accidentally damaging the top of the root. Damaged roots are susceptible to canker (see Problem solving, below).
Once the crop is growing strongly, the dense foliage usually hinders weed growth.
Water young parsnips regularly until well established. More mature plants are fairly drought tolerant, but to avoid the roots splitting, keep the soil evenly moist, especially during dry spells.
Spread a thick layer of mulch, such as garden compost, around plants when the soil is warm and damp, to hold in moisture and suppress weeds.
Parsnips are vulnerable to carrot fly damage (see Problem solving, below), so it’s best to put protection in place from the start. Cover the crop with insect-proof mesh or surround it with a 60cm high barrier.
Parsnips are ready to lift when the leaves start to die down in late summer or autumn. It’s a good idea to wait until after the first heavy frost though, as this intensifies their sweetness and flavour.
Make sure your crop is clearly marked with canes or labels before the leaves disappear, so the roots are easy to find in winter.
Use a garden fork to carefully ease the long roots out of the ground intact. If the soil is dry, watering first can make harvesting easier.
Parsnip roots are very hardy, so can be left in the ground into winter and harvested as required. Still, they can be difficult to harvest from frozen ground, so it may be worth lifting a few extra in November to ensure you have parsnips to enjoy however cold it gets. Alternatively, cover the ground with fleece or straw as insulation.
Parsnips are generally healthy and problem free, but seed germination can be poor and slow, especially in cold soil, so don’t sow too early. Always use fresh seeds and protect sowings with a cloche to keep them warm and aid germination.
Roots can fork in stony or compacted soil, or if manure or garden compost have been added recently. Roots can also split if growth is erratic, so water regularly in dry spells to avoid this.
Parsnips can suffer damage from carrot fly, so put protection in place early.
Parsnip canker (an orange/brown rot) can affect the roots, especially if damaged, in dry conditions or in overly rich soil. Resistant varieties (‘Avonresister’ and ‘Archer’) are available.
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