How to Grow Celeriac

, written by Benedict Vanheems gb flag

Celeriac 'Ilona'

Celeriac is one of our more obscure, less-grown vegetables. Its gnarled stone-coloured roots are never going to win it any prizes in the beauty pageant but, like those tanned and toned beauty queens, it’s what inside that should really count – and these relatives of celery have a rich and sensuous soul behind that seemingly ugly exterior!

I suspect many of us are put off growing celeriac because of our previous encounters wrestling to prepare the roots for the pot. True, they require a bit of fiddly peeling but the taste is worth it. Nutty, mildly spicy and with hints of celery, it’s a charismatic sort of vegetable that’s as happy in a stew as it is grated to contribute a fresh punch to salads.

What to expect

My experience of growing celeriac is this: You start it off in spring, nurture the seedlings slowly along, plant them out then wait all summer, inspecting the undergrowth daily with a building sense of paranoia as the roots fail to swell! But then, all of a sudden, they’ll pile on the pounds as if they’ve suddenly clocked that they need to lay down fat for winter. From late summer to autumn those roots will swell and swell, rewarding all your patience. The knack is simply not to panic – they’re just late starters.

Celeriac growing in the garden

I have only ever grown the widely recommended and available ‘Prinz’, which never fails to produce manly, fist-sized roots of excellent condition. If you want something that’s easier to peel then give ‘Monarch’ a go. This regal-sounding variety has smoother skin and tenderer flesh, which should make work in the kitchen less of a caffufle.

In the nursery

Celeriac needs quite a long growing season, so if you are growing in a temperate or cold climate start the seeds off under cover in early spring. Sow the tiny seeds thinly onto the surface of seed compost. Don’t cover the seeds as they need light to germinate, though popping a sheet of glass over the seed tray or pots will ensure a cosier microclimate suitable for germination. Gentle warmth will also coax them along, so do all this on an indoor windowsill or propagation area of the greenhouse.

Celeriac seedlings

Like their delayed root swelling, they like to tease the ever-patient gardener, taking as long as three weeks before the seedlings finally make an appearance. Once large enough to handle they can be carefully levered out of their seed tray from below (using a pencil or dibber) and planted into ready-filled modules/cells or biodegradable pots, as pictured. I prefer biodegradable pots as it avoids disturbing the roots at planting out time.

Out to bed

Plant your celeriac out by the end of spring only after any remaining risk of frost has passed. Acclimatise your seedlings to outdoor conditions beforehand by leaving the young plants outside for increasingly longer periods, bringing them under cover at night. A cold frame makes a handy halfway house for this purpose.

Planting out celeriac

You can plant your celeriac out at anything from 37cm (15in) to 45cm (18in) apart in each direction. Wider spacings will give bigger roots but obviously fewer celeriac per unit area, while a closer spacing will give more average-sized roots. Where you go between these two extremes really depends on what you want and how you want to use the roots.

In any case, plant your celeriac into firm, fertile ground that’s been improved with either compost or well-rotted manure. If you’re reading this in a cooler part of the world (British Isles, northern US/Canada, temperate parts of the Southern Hemisphere) then you’d be advised to cover newly planted celeriac with a protective blanket of horticultural fleece. Not only will this smooth the transition to outdoor conditions, it will hide your plants from the likes of hungry rabbits while creating a slightly moister atmosphere. Remove the fleece as soon as the plants have grown on a bit.

Smooth progress

Keep plants watered but not overly so – only reach for the watering can or hose if the ground is dry and it hasn’t rained for a week or more. It goes without saying that weed-free soil will reduce competition, helping plants establish and, later on in summer, put on their girth. Feel free to remove yellowed leaves from the lower part of the crown but don’t pull away leaves unnecessarily, as these will capture the sun’s energy and turn it into root.

Young celeriac plant

The roots will be ready as soon as they look big enough, which will be from mid-autumn onwards. Roots can be left in the ground and cut free as needed but if slugs are an issue in your garden you may be better off lifting them all for storing in a cool, dark and well-ventilated place such as a garage. Leave a bit of soil on them and raise them up off the ground away from potential vermin. Some of the roots will keep all winter long, proving well-worth the wait – and their weight!

Photo credit for DTB Celeriac 'Ilona F1'to D T Brown

By Benedict Vanheems.

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Comments

 
"Can you also eat the leaves? They look like they might be good as well"
Connie on Thursday 11 April 2013
"Hi Connie Celeric leaves are indeed edible. Use young leaves in salads for a gentle, celery-like taste. They can also be swirled into soup as an alternative to celery. Or try using them as a garnish."
Ben Vanheems on Friday 12 April 2013
"My wife and I went to southern France last year, our first trip to Europe for both of us. As a gift she bought me (us) cooking lessons at a 4 Star restaurant in a small village. i got to choose what I wanted to learn and I asked for ideas on making fall vegetables more interesting, Celeriac was one of those and I am in love with them and started growing them this year."
Steven on Friday 10 May 2013
"Thanks for your advice which conveys a nurturing approach to these appealing vegetables. So far my celeriac roots have been tasty but puny. After reading your instructions, I can see that I haven't provided the ideal growing conditions. I shall in future. Antipodean gardener."
Mary Greenfield on Wednesday 15 May 2013
"Thanks for your advice which conveys a nurturing approach to these appealing vegetables. So far my celeriac roots have been tasty but puny. After reading your instructions, I can see that I haven't provided the ideal growing conditions. I shall in future. Antipodean gardener."
Mary Greenfield on Wednesday 15 May 2013
"My celeriac has been growing forever ! - all through the long winter - I planted it out last spring! - it is shooting up now - should I keep the stems from bolting? They are getting very tall and look as if they will go to seed ... the roots have not swollen :-("
Emma on Tuesday 18 June 2013
"I am growing celeriac for the first time and have followed instructions for growing but my plants seem to be growing flower heads or is this just vigorous leaf growth."
Maurice Salter on Thursday 20 June 2013
"Hi Emma and Maurice. It sounds like your plants are bolting (going to flower). Emma, celeriac will flower in its second season so it's probably best to have started with fresh seed this spring. Marice, keep plants well watered and weed free so that plants are completely stress-free - competition and very dry conditions can lead plants to bolt. Of course, the vigorous growth my just be foliage - so maybe wait and see what develops."
Benedict Vanheems on Wednesday 3 July 2013
"My celeriac were looking really good but I have been watering in this dry spell and some are now producing flowers. Will this spoil the roots, do I cut off the flowers or leave them be.What do I do to stop the others from bolting."
Julia Parker on Sunday 7 July 2013
"Hi Julia. If your plants are bolting then this will stop the roots from swelling. The same advice applies here as my previous comment above yours - keep on with the watering and maintain weed-free conditions. Plants should be properly spaced too, or they can become stressed and bolt. If all the plants do bolt, opt for a bolt-resistant variety next year, such as 'Prinz' or 'Alabaster'. "
Benedict Vanheems on Thursday 11 July 2013
"Hi, I too am growing celeriac for the first time from plants purchased from a garden centre. Some have bolted too, do I remove the flower stems?"
Sue on Friday 16 August 2013
"HI there, I grew mine from seed and they are only about 6 inches tall although I started really early. Really frustrating! Is it worth waiting it out? Sarah"
Sarah Laing on Tuesday 20 August 2013
"Hi Sue. You could try removing the flower stems but I fear that once they've bolted they probably won't settle down to produce a decent bulb, so it's probably best to start again next year, ensuring all the conditions you offer are optimal. Keeping plants well watered and weed-free will help considerably."
Benedict Vanheems on Thursday 29 August 2013
"Hi Sarah. There's a very good chance that your plants will still come on. There's at least a month and a half of growing season left, so hang on in there. Keep plants watered in dry weather to ensure steady growth."
Benedict Vanheems on Thursday 29 August 2013
"Hi , Im Cori I live in Capel a small town in the Southwest of Western Australia, Australia. I would love to have a go at growing these Celeriac, from seed.Do you think they would grow down here. The weather has been typically cool and wet as Spring goes,but we are starting to have nice warm days but still having cold nights,. Can you also tell me where I can buy seeds from.? Regards, Corinne Young "
Corinne Young on Monday 14 October 2013
"I did remove the flowering stems on my celeriac and I think the only problem was that the roots were smaller. I picked the first one last week it weighed in at about 600g and I made some delicious soup with it."
Sue on Monday 14 October 2013
"I'm completely confused and frustrated! I've loved celeriac all my life. I grew up in Germany where it is a common root vegetable. I live in USA Zone 7, in Pennsylvania. Last year I built a hoop house,and in very early spring I sowed celeriac inside it. For the longest time nothing at all happened. Now it is midOctober, there are some bolted plants, one with a plum-sized root - and a gadzillion 3 inch tall, healthy-looking seedlings. Our median first frost date is 10/15 - that's tomorrow! What, if anything, can I do to save them and maybe even get a harvest?"
Hanny Budnick on Monday 14 October 2013
"Hi. I am growing celeriac for the first time from seed. There is no mention of watering at the early stage. Can you tell me when you commence this process."
Ronald Stanford on Saturday 8 March 2014
"Hi I am growing celeriac for the first time too. I started last year. My celeriac was well watered and kept weed free. The roots didnt seem to want to grow but had a load of leaf, I kept trimming back the outermost leaves after finding advice on the web to do so. I got really excited when the roots started to swell - but I looked today and all the stems have also grown really thick and tall - it looks like they are bolting, does this mean the roots will be inedible, after all my waiting? Thank you "
Caracroft on Tuesday 8 April 2014
"Hi Caracroft. It sounds like it is indeed running to seed, so the roots will not be of any use from here in I'm afraid. I'd start again. I've not heard of removing leaves and am not sure how this would help - more leaves means more energy to go into root formation."
Benedict Vanheems on Wednesday 9 April 2014
"Hi, I live in Hawkes Bay NZ and have a very small garden. Is it possible to grow celariac in large pots?"
Jean on Tuesday 9 September 2014
"Hi Jean. Lovely part of the world you live in! Yes, it should be possible to grow celeriac in pots, but they'd have to be quite big ones to account for all of the foliage. I've never tried them in pots but I see no reason why they shouldn't succeed if given enough space. I'd go for a pot that's at least 30cm deep 60cm wide - you should be able to get at least four or five plants in a pot this size."
Benedict Vanheems on Tuesday 9 September 2014
"Oh I can't wait! Just started seed indoors a month ago. This is a very timely article."
Claudia Maskeroni on Tuesday 3 March 2015
"I grew my celeriac all through the winter. I harvested the last few a couple days ago, worried that they had probably gotten real touch or pithy. I was very wrong. What a nice surprise from a veggie I have only begin to grow."
Steven on Tuesday 3 March 2015
"Jean here from Hawkes Bay, New Zealand. I asked earlier if it were possible to grow celariac in pots and I can now report that indeed it is. I put 12 plants in, one per pot and they are enormous. We have harvested one to try and it was superb. Highly recommended if you are short of space. I planted in a combination of potting mix and compost and will be interested if anyone else has such good results."
Jean on Wednesday 4 March 2015
"Hi Steven - great news you've managed to grow them successfully - hearty congratulations to you! Jean - well done on getting them to grow in pots. It sounds like you've got the perfect recipe for success there. Thanks for letting us know how you got on."
Benedict Vanheems on Wednesday 4 March 2015
"Hi Benedict, I have appreciated your advice and he experiences of others on this blog. My query: this year my celeriac is better than it was last year, but still not as big as the bulbs in the shops. However there's a new development: I have just cleaned one to cook and it had purple marking in it, like in kumara. I was uncertain whether it was OK to eat it. Raw it tasted a little bitter, so I cut it all out as I didn't want to cause us to have indigestion. Maybe it was perfectly alright, but I don't know. Do you?"
Mary Greenfield on Sunday 19 April 2015
"Hi Mary. I have to confess I'm not sure what this could be. It's highly unlikely it would harm you, but I think cutting out the affected area - if only to get rid of the bitter taste - is a sensible precaution. Does anyone else have any insight into what might be causing these purple markings?"
Benedict Vanheems on Sunday 19 April 2015
"a freind of mine participates in a co-op for fresh fruits and veggies, this last week they had a Garden Starter pack you could buy, with potatoes, garlic, yams, and a Celery Root (celeriac) anyway the intention of this pack was to be things you could start in your garden. I have not found anywhere online where you could start celeriac from the root ball almost as if you do with a potato, I have only found where you start from seed, can you help? is it possible to that way? "
Shasta on Monday 20 April 2015
"Hi Shasta. I have never done this myself. You could probably get the root ball to root and produce foliage, but you wouldn't get any further celeriac roots for harvest. The only way to ensure plenty of healthy roots for harvest is to grow from seed."
Ben Vanheems on Thursday 23 April 2015
"Hello, please can you help me? My celeriac seems to have pushed itself out of the ground. Should I earth them up like I would potatoes? "
Joan Ball on Sunday 25 October 2015
"Nothing has changed since exactly one year ago! I still have lots of young, 6 " sprouts with several sets of leaves, and the skinniest possible roots. Keep them in the ground or pull them out and eat the leaves? "
Hanny Budnick on Sunday 25 October 2015
"This is the first year I have grown celeriac. It was well worth it! I live in central Maryland and have been harvesting them for the last few weeks. I love how versatile it is whether it is raw, roasted, boiled and mashed, or puréed , I am in love with it. "
Claudia Maskeroni on Sunday 25 October 2015
"Hi Joan. The celeriac root/bulb often pokes quite high out of the ground - this is perfectly normal. There is no need to earth them up, as long as the fine roots at the base of the bulb are still fully covered you will be fine."
Ben Vanheems on Monday 26 October 2015
"Hi Hanny. I'm not sure what to suggest here. Are the plants getting enough light and soil moisture? It does sound like your plants aren't going to go much further, but it is probably worth leaving them in the ground for the rest of fall/autumn to see if they start swelling. Otherwise start again next spring with fresh seeds and a new area of the vegetable garden. Sorry I can't be of much more help!"
Ben Vanheems on Monday 26 October 2015
"Thanks, Ben! It's kind of late to wait for them to change their shape before hard frosts (I'm in Philly, Zone 7), I'm considering transplanting a few and watch what happens. They have light, always had moisture - grrrrrrrrr, but I don't have celeriac! Commercial ones are very expensive and usually not good."
Hanny Budnick on Monday 26 October 2015
"How to prevent hollow (very soft) centers of the celeriac bulbs? Also, some of the bulbs have cavities open from top. Thanks for advise."
Jerry on Tuesday 3 November 2015
"Hi Jerry. The key to good, solid bulbs is to ensure there is plenty of soil moisture for the plants to take up, as well as nutrients. Make sure you add lots of organic matter to the soil the next time round and keep plants well watered in very dry weather so that they continue to grow on smoothly."
Ben Vanheems on Tuesday 3 November 2015
"Thanks, Ben. Interestingly, last year i bought truckload of a compost, spread a 2in layer over the whole patch, so practicaly the celeriak should not complain. The whole area was dense with tomato plants, and soil was never too dry. I do not know the brand of the seedlings, i bought them on the farmers market. I am in Buffalo NY."
Jerry on Tuesday 3 November 2015
"What is eating/damaging my celeriac - they all have black parts inside them. It is a clay soil. No vegetable growth on it at all only grass previously. They are also not very big."
Lesley on Friday 24 February 2017
"Hi Lesley. It could be that your celeriac are being attacked by carrot fly, which would leave cracks, some of which may be black/dark brown when cut open. As your bed was converted from grass, there is a chance the attack could be from wireworms. Details here: http://bigbughunt.com/bug-guides/us-and-canada/wireworm/ "
Ben Vanheems on Monday 27 February 2017
"Hi there , this is my first year with a bed of celeriac . The you plants are in and netted with slug pellets down . A fellow plot holder has told me that he has struggled with the growing of these for the last couple of seasons as the bulb constantly comes out small . He has been feeding the plant chicken pellets ( is this his problem ? ) can you recommend a better food for mine By the way .. I'm not going to tell him the secret if mine come out good ! "
Matt on Sunday 9 April 2017
"Hi Matt. I'd say chicken pellets would be a good general fertiliser to use. The key thing is to have the ground nicely enriched with plenty of garden compost. I'd also water the plants in dry weather, to help them swell. Also make sure they have enough space between each plant - if they're planted too close they may grow too small, so this could have been part of the problem. Good luck!"
Ben Vanheems on Sunday 9 April 2017
"We have successfully grown celeriac for the last few years. Always use Monarch seeds. Don't bury them, scatter them on the surface of modules to germinate, indoors in mid spring. Harden off and then transplant into a well composted bed when they're getting up to about 10 cm tall, after frosts have passed. Water about once a week, unless it has been raining. Net them if you have carrot fly. Feed with a small sprinkling of blood fish and bone, or chicken pellets, around once a month. The bulb is a swollen stem and grows above the soil. They don't really grow much until late Fall/Autumn when it gets cold! I've left them out in mild frosts without any problems. When the frosts are forecast, we dig them all up, peel and cube them. Boil up and mash them all, and divvy up into portions in food bags for the freezer. Then take out on the morning that you want to use them and defrost in the fridge. "
Will Mainwaring on Thursday 6 July 2017
"Brilliant - thanks for sharing your tips there Will. Some really good advice there. I think regular feeding is possibly what makes the difference between mediocre celeriac and super celeriac."
Ben Vanheems on Thursday 6 July 2017
"I've grown celeriac for years and now for the first time we are getting soft brown spots in the interior of the vegetable, harvested in late November. Any idea what this is?"
Rachel Goodman on Monday 4 December 2017
"What causes brown spots inside the mature celeriac? "
Rachel Goodman on Monday 4 December 2017
"Hi Rachel. This could possibly be down to carrot rust fly, which burrows into the roots to feed on them. Or there is a chance this could be slug damage too. I've had potatoes dug up as you describe - ravaged on the inside by slugs to leave a soft, brown goo at the centre."
Ben Vanheems on Monday 4 December 2017
"My celeriac is looking good, nice rounded balls sticking out of the earth. I bought seedlings and planted in May. I've heard that the flavor improves after the first frost. Should I leave them? I'm in Zone 5 in Canada."
P.J. on Thursday 4 October 2018
"Celeriac is hardy and generally does sit through frosts, so they can be left where they are until needed. However, if the ground is likely to freeze solid then consider covering them over with a thick layer of straw or similar to keep them somewhat protected. Alternatively lift all the roots up after a few frosts but before the ground freezes solid, then store somewhere cold but frost-free."
Ben Vanheems on Thursday 4 October 2018
"Hi, do you have any advice on how deep to plant out the seedlings? I presume to the base of the leaves only but have never had any luck so thought I'd ask. Thanks for any help."
Sue on Friday 4 January 2019
"very interesting thread. Just thinking about growing celeriac next year. Bought one at the grocery store today for $3.86 (and it was small) so should save me some money. Thanks everyone for your contributions."
Miriam Kearney on Sunday 29 September 2019
"We planed seedling early spring and now they have thick dark green almost 70 cm tall leaves and start growing flower stalk. We try out few times and only ones when it seeded it self and we did not 'look' after, it developed bulbs. We using mostly cow manure and little of chicken manure in our garden. Boze and Stan NSW Australia "
Bozena Daniel on Sunday 29 September 2019
"Thanks for that Daniel - sounds like the hands-off approach is working best for you."
Ben Vanheems on Monday 30 September 2019

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