Top Of The Crops - Parsnip

Growing Parsnips in a Polytunnel

Parsnips require a big investment in terms of time and space but if you have a large enough polytunnel then you may like to grow some parsnips in it. Parsnips are a versatile vegetable that were once a staple like potatoes are now. 

Parsnips can be eaten mashed, roasted or boiled in a wide range of different recipes and though they have a strong flavour, can be delicious when cooked well and combined with the correct flavours.

Key Information

Parsnips are a root crop, or root vegetable, the roots of the plant Pastinaca sativa. Like carrots and parsley, their close relatives, they are members of the Apiaceae plant family. Modern varieties are all derived from the wild parsnip, native to Eurasia. 

Parsnips grow only relatively slowly. But get your gardening right and the delicious and healthy yields you can obtain can make the wait worthwhile. 


The Preferred Conditions for Parsnips

To grow well, parsnips need:

  • A position in full sun. 

  • Fertile, light soil that drains freely and which is not stony or compacted. 

Provide the right growing conditions and you should find that parsnips are quite easy to grow, and will not need much of your time or attention. 

You can grow parsnips in the ground, in raised beds, or even in containers as long as you provide the right care. Raised beds can often be ideal for parsnips, especially if you have a heavier or stonier soil where you live. 

Recommended Parsnip Varieties

Choosing the right variety can make all the difference when growing parsnips. Here are some our top parsnip picks:

  • All-American’: Boasting tapered, 10-12-inch white roots, this variety is known for its high sugar content and excellent storage capabilities.
  • Harris Model’: These smooth, tapered, 10-inch white roots are free of side roots, making them a gardener’s favourite.
  • 'Hollow Crown’: With mild, 12-inch white, fine-grain roots, the flavour of this variety notably improves after a frost.
  • Kral Russian’: An heirloom variety, it’s characterised by its beet-shaped root, making it ideal for shallow or heavy soil.
  • ‘Albion’ RHS AGM: This variety is known for its resistance to canker. It boasts long, smooth, white roots that have a delightful sweet taste and pleasant texture. Plus, these roots store exceptionally well.
  • White Gem’: A dependable choice, the ‘White Gem’ offers a sweet flavour and is also resistant to canker.
  • Archer’ RHS AGM: This variety stands out for its impressive yields and taste. It’s also notable for its canker resistance.
  • Palace’ RHS AGM: A high-yielding variety, ‘Palace’ is another excellent choice for those looking to avoid canker issues.
  • Gladiator’ RHS AGM: Perfect for those with heavy soils, the ‘Gladiator’ is celebrated for its rich flavour.

With these parsnip varieties added to your garden, allotment, or domestic polytunnels, you are bound to achieve great results. 

What you will need to grow Parsnips

To grow parsnips you will need:

  • Parsnip seeds.

  • A suitable growing location where you can provide the above preferred conditions. 

  • Facility to provide water for your crop when needed. 

  • Organic matter for mulching.

  • Fork or spade for harvesting the root crop. 

How to Grow Parsnips

Parsnips are not at all challenging to grow, though the seeds are often said to be tricky to germinate successfully. Follow the seed sowing instructions below and you are more likely to meet with success. 

Sowing Parsnip Seeds

Growing parsnips from seed worries some new gardeners because it is said that they can be difficult to get to germinate successfully. But if you choose the right location to sow your seeds, and get the timings right, you should have good results. 

Parsnip seeds need to be sown directly where they are to grow. They form tap roots and do not transplant very successfully. Germination rates can indeed be patchy if the seeds are sown too early – as it can be too cold for the seeds to sprout well. 

The right timings depend on precisely where you live. In the very mildest of regions, seeds might be sown as early as February but usually it is best to wait until at least mid-March, April or even May – especially in colder regions and further north. You should wait until the temperatures are around 12 degrees C. for best results. 

When sowing parsnip seeds you should sow into shallow drills around 1cm deep, sowing the seeds thinly along these drills. If you are making more than one row, these should be around 30cm apart. 

It is a good idea to mix in some radish seeds with your parsnip seeds to mark the rows and to make the most of the space. 

The radishes will germinate and appear far quicker than the parsnips, which will take around three weeks or even longer to appear. The radishes will mark your rows and will then be harvested before the slow growing parsnips need the space. 

Harvesting Parsnips

By the time autumn rolls around, your parsnip roots should have fully matured, allowing you to begin harvesting as needed from September onwards. To make the process easier, it’s a good practice to loosen the soil around the roots before pulling them out. 

Typically, parsnips reach maturity in about 16 weeks, depending on the variety, and it’s ideal to harvest them when the roots are at least 1 inch in diameter. While a few frosts can enhance their flavour, it’s essential to harvest your parsnips before the ground becomes a frozen bed.

If you want to allow more time for your parsnips to grow, they can still be grown throughout the winter, so long as you provide plenty of mulch for protection, and then harvest them in early spring. Sometimes it is hard to keep track of the harvest season, hence we have created a useful guide on when is harvest season in the UK.

NOTE: if you notice a flower stalk developing, it’s a sign that the roots might have turned woody, affecting the texture and taste of your parsnips.

Storing Parsnips

Parsnips will often be best left in the ground as mentioned above until they are needed. But where the ground freezes completely, you may wish to lift and store the roots after they have experienced a few light frosts. 

You can store undamaged roots of parsnips that are in good condition in a root cellar or other cool, dark location for several months. Like carrots and some other root crops, they are best stored in damp sand or potting mix or sawdust. 

If you do not have a suitable storage location where you live, you can also lift parsnips, slice, par-boil and freeze them, or use a pressure canner if you have one to preserve them in a range of recipes. 

Of course, there are also plenty of parsnip recipes you can use to use your harvest up right away. 

Care Tips for Parsnips

Parsnips are not challenging to care for,  but you do need to make sure, over time, that the crop's basic needs are met. Making sure that you eliminate additional competition due to overcrowding or weeds is very important, and of course you need to make sure that parsnips receive enough water especially through the summer months. 

Thinning Out Seedlings

Thin parsnip seedlings to a spacing of around 15cm when they are 2-3cm high. Take the weakest seedlings and leave the strongest in place to continue to grow. 


They thrive without additional feeding. Just ensure the surrounding area is weed-free to prevent competition.


Since parsnips are quite slow growing, it is important to keep on top of weeding, so that young parsnip plants don't have to compete for water, light and nutrients. Weed by hand, carefully, so that you do not accidentally damage the tops of the parsnip roots. 


Parsnips don’t demand frequent watering. In dry conditions, water them every two to three weeks.


Mulching around parsnip plants with organic matter, such as homemade compost or well-rotted manure will help to suppress weed growth to a degree, enrich and protect the soil, and conserve soil moisture. 

Pest Protection

Like carrots, parsnips can encounter issues with carrot fly. Where carrot fly is present, it is usually best to cover the crop from the start with insect-proof netting, which will prevent the carrot flies from laying their eggs around your parsnip crop. 

Common Problems for Parsnips

When growing parsnips you will not typically encounter too many serious problems. However, things can of course go wrong if you get your timings wrong, especially if you sow the seeds outdoors too early. 

Issues can also arise if you have not chosen the right growing location and if the primary growing needs of the plants are not met. Roots can fork, for example, if the soil is too compacted or stony. Roots may split if you do not water enough during dry spells. 

Pests may occasionally also arise – most commonly carrot fly. This is why, as mentioned above, it can be a good idea to cover your crop from the very beginning with fine mesh netting, and to think about companion planting as an additional deterrent to these pests. 

Occasionally, you may encounter diseases too. Parsnip canker, for example, is an orange or brown rot that can affect the roots in dry conditions or overly fertile and rich soils or growing media. Some varieties are more resistant than others to this problem, such as 'Avonresister' and 'Archer' for instance, and the AGM option 'Albion' listed above. 

Pests/Diseases Variety Signs/Symptoms Prevention
Aphids Insect

Miscoloured leaves (yellow)

Sticky honeydew

Black mould

Plant companion plants.
Use water spray. Place banana or orange peels around plant. 
Wipe leaves with washing up liquid and wash off every 2-3 days. 

Canker Fungus

Dark coloured textures appear on crown or shoulder of foot (red, brown, black or purple).

Green halos on leaves with orange-brown spots

Opt for resistant parsnip varieties.
Rotate crops.
Cover exposed root.

Carrot rust flies Insect

Wilted plants.

Rust coloured excrement on roots. 

Root rot. 

Add row covers.
Destroy crop remains.

Leaf miners Insect Blistered leaves - caused by larvae.

Remove affected leaves.
Use weeding methods. 
Add row covers.
Rotate crops. 

Top Tips for Growing Parsnips in a Polytunnel

Using commercial polytunnels for growing parsnips can lead to some unique results. In the controlled temperature environment of a polytunnel, parsnip seedlings can become prosperous, often reaching lengths of 20-25cm. However, once transplanted, these seedlings tend to adjust and stabilise.

Many gardeners prefer direct sowing of parsnips in raised beds, avoiding the transplanting process altogether. Yet, growing parsnips in biodegradable pots within a polytunnel can work just as well. This method ensures minimal root disturbance during transplantation.

Using polytunnels for parsnip growing is beneficial especially during colder months, due to the warmer conditions inside the device. This can result in taller stalks, sometimes reaching up to 25cm. Over time, these shoots will yellow, wither, and be replaced by the more familiar, robust parsnip foliage.

If you do not yet have a polytunnel erected in your garden, allotment, or other green spaces, then do not worry, because we can help with that! Opt for our construction services to get your polytunnel built quickly and effectively. 

Cooking Notes

Remember, parsnips certainly do not have to be boring. You can cook them in many different ways. Roasting, however, is a tried and tested favourite and is, in my opinion, the best way to enjoy the parsnips you have grown in your garden. Drizzled in olive oil and honey their sweetness will come to the fore.  

Enhance Your Parsnip Growing Experience

Growing parsnips requires understanding soil preparation, care, and the right harvesting time. With these essentials in place, both beginners and experienced gardeners can achieve a successful parsnip growing experience. Dive into the process, and soon, you’ll enjoy the fruits (or rather, roots) of your labour.

If you enjoyed this growing guide, we have a vast amount of other articles for you to dive into about other familiar or unfamiliar fruits and veg for you to grow, including our advice on what is amaranth




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