How to Grow Romanesco Cauliflowers

, written by Benedict Vanheems gb flag

Romanesco cauliflower

Some vegetables are born showoffs. It may be because they're loud (super-sized pumpkins), blousy (curly kale), or just plain beautiful. The Romanesco cauliflower fits into the latter category, and the precision of its intricate, geometric heads, or curds, really does earn it admiration.

The Romanesco is a member of the cabbage family. For the sake of this article and to keep things 'tidy' I've called it a cauliflower. But, the truth is, it's in a class of its own – neither cauliflower nor broccoli but somewhere in-between. Hailing from northern Italy, this approximately 500-year-old brassica has all the hallmarks of Italian design. It's suave. It's sophisticated. And it promises impeccably good taste!

Stare into its fractal curds and you really begin to appreciate the sheer wonder of nature. Grow it for yourself and you may struggle to bring yourself to eat this good looker. If you can, prepare to be rewarded with a sweet, nutty flavour and crisp texture that makes this showoff taste every bit as good as it looks.

Sowing Romanesco Cauliflower Seed

Sow from spring to midsummer to give a succession of curds. Like all brassicas, Romanesco cauliflower is best started off in a fertile seedbed or in modules of potting soil. I prefer using generous-sized module trays because this produces really solid plants, while minimizing root disturbance at planting out time. Aim for a cell size that's at least 5cm (2in) across. Start your earliest seedlings off under the protection of an unheated greenhouse or cold frame.

Sow the seeds 1cm (0.5in) deep, sowing two to three seeds per cell. They can be thinned out to leave the strongest seedling once they have all germinated. Given a little warmth they may pop up in as little as four days, but allow up to two weeks. The seeds need a minimum temperature of 10°C/50°F to germinate but once they're up the daytime temperature can happily hover around 7°C/45°F with no negative impacts on the seedlings.

Young plants that have been started off under cover will need to be hardened off before they are planted out. This will stop them from sulking at the sudden transition from relative warmth to cold. Hardening off is especially important in temperate regions or in a slow season where spring is late in arriving. To harden plants off, leave them outside during the day and bring them back under cover at night, gradually increasing the length of time plants are out of doors over a period of one to two weeks.

Brassica seedlings in modules

Planting Out Strong Seedlings

Romanesco cauliflowers need fertile soil – perhaps improved over the winter with plenty of well-rotted manure or compost. A final flurry of bone meal or similar organic fertilizer at planting time will encourage strong root growth.

Plant seedlings out into their final positions once they are 10-15cm (4-6in) tall. The closer the spacing, the smaller the curds, so it's really up to you how far or near you plant. I aim for 60cm (2ft) between plants and 60-90cm (2-3ft) between rows. This might seem like a lot of space, but you can always sow a quick-to-mature catch crop, such as salad leaves or radishes, in-between the rows while the plants are still young and don't need that extra space.

To plant, dig a hole for each plant then ease the root ball from its module, disturbing the roots as little as possible. Firm in really well then 'puddle' the soil around the plant by thoroughly watering the ground to further settle the soil around the roots.

Once the plants are in the tricky bit's over – just keep your Italian charmers well watered in dry weather (water at the base of the plant to avoid splashing the leaves) and check and treat for insect pests such as cutworm.

Brassica seedlings planted out

Cooking Romanesco Cauliflower

When it comes to cooking Romanesco cauliflower, less is definitely more. Prepare harvested curds by rinsing them under cold water before cutting out the central stalk so that the individual florets fall away. Plunge the prepared florets into a pan of boiling salted water and cook for no more than five minutes. You can also steam them.

Serve with a grind of salt and pepper and perhaps a small knob of butter for a luxuriant finish. The florets are delicious partnered with Parmesan cheese, a hint of lemon juice or roasted garlic cloves. Or serve the florets raw for a crunchy texture in salads.

Photograph at top of page courtesy of Suttons Seeds

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Show Comments


"I don't have a traditional garden, I have a hydroponic system set up on my town house balcony. How much do these like water? Do you think they would work well in a hydroponic environment? I really love these when I can get them in the store, I would love to try to grow a few! "
Alex on Friday 6 March 2015
"Hi Alex. I have to confess that I have no personal experience of growing with hydroponics. I know that brassicas like firm soil, so the lack of root support may be an issue and imagine they might get very top-heavy in such a system. But then the only way to find out is to give it a try. If you do - let us know how you get on."
Ben Vanheems on Friday 6 March 2015
"I will do Ben. The system I use starts the seeds in rock wool, and then I insert the entire sprouted seed, rock wool cube and all into fired clay pellets inside a net pot, which gives the roots stability and support. The net pot then sit in holes drilled into corrugated drain pipe, so the plant, if it needs it has some support as well, to the sides. I will be adding some container plants to my garden this year, I might plant the majority of the Romanesco in there instead and just plant one plant in the hydro, to see how it goes."
Alex on Friday 6 March 2015
"Hi Alex. That sounds like a good plan. Very curious to see how you get on - keep us posted!"
Ben Vanheems on Friday 6 March 2015
"Alex, Some food for thought - The way I see it, just maybe(?) it might be a good idea to plant three in the hydroponic system instead of only one? My reasoning is that may be possible for you to end up with better criteria for the results of your experiment. And ultimately, if something goes wrong with only one hydroponic specimen you won't be able to tell if it's the system that is causing that problem or if you just got a bad seedling. By planting only one specimen you will have nothing to compare to other than your garden specimens. However, if you go ahead and plant three specimens in the hydroponic system, then you will have specimens in that system to compare to, as well. With more than one plant you will be able to see if they all go bad or just one or two. When the time comes, you could simply take the best two out of three, if necessary. So, you see, planting multiple plants may possibly give a much better indicator at the end as to which system this vegetable gets along with better or if it likes both systems equally."
Julie on Friday 6 March 2015
"Julie, You are absolutely right. I may try that. However I only have a 6x7ft balcony. Even with the drainpipe on two levels, around 3 sides of the balcony, I have limited space. If I have planted the lettuces and herbs and have enough room, I will give the Romanesco more room for certain. It is true that in order to have verifiable results, I should have a greater sample size. I will update regardless. If anyone else who is using hydroponics wants to give it a try, that would be helpful too! I encourage others to try it. its pretty easy, once you get it set up."
Alex on Friday 6 March 2015
"Cool, Alex, unfortunately, I don't have a hydroponic system to do this with. But, will it will be interesting to see what you and any others come up with. Good Luck! "
Julie on Saturday 7 March 2015
"Wish you would have added some information about approx. how long they take to start bearing edible sized heads. Thanks for this info though."
Thom Foote on Wednesday 27 July 2016
"Hi Thom. Like other cauliflowers, the Romanesco types would take around five to six months to reach maturity and harvest time."
Ben Vanheems on Thursday 28 July 2016
"I've grown these beauties. Super yum factor as well as impressive in garden. 3 plants fit in a 4ftx 6ft bed. I staked them for added support. When harvested while tight solid heads they taste more like cauliflower. If you wait a bit to harvest just till the heads loosen just a bit then they taste more like brocccoli, with the tenderness of cauliflower still. Really excellent crop. We had huge 14 inch heads at this spacing. "
Shannon on Wednesday 8 February 2017
"Wow, 14 inch heads is a good size! It is a very special crop."
Ben Vanheems on Thursday 9 February 2017
"I have some of these fine plants that are about 12" high. No sign of any "fruit". I have purchased these at Farmer's Market, so I know they grow here. I had the same result last year, no fruit. The soil has been composted, plants are fed liquid fish solution. We are waiting and watching."
Orinda on Monday 31 July 2017
"Good luck Orinda. I hope this season proves more successful for you. It certainly sounds like they're getting lots of love and care!"
Ben Vanheems on Wednesday 2 August 2017
"i've grown romanesco for past 5 garden seasons (zone5-a, south shore of lake ontario)with mixed results. the plants get 3 - 4 ft. tall (need staking) and they bush out super-well, but i struggle to get heads on the mature fruit. they may be finnicky to hot weather and i probably should plant them late june so they aren't as subject to hot july weather. i have had better results planting in a direct seeding method than from growing sets and transplanting. i was hoping this particular website would help me out but no such luck. i is worth the effort if you give it a grow."
doug on Tuesday 10 October 2017
"I've heard Romanesco described as what happens when a cauliflower crashes into a pine tree :) Just a little smile for the day....."
Sue on Friday 25 May 2018
"That is a great way of describing them Sue!"
Ben Vanheems on Tuesday 29 May 2018
"Does Romanesco produce smaller heads like broccoli after you harvest the main head? "
'Netta on Saturday 23 June 2018
"Hi Netta. Yes, once the main heads are harvested smaller heads will follow within a few weeks."
Ben Vanheems on Monday 25 June 2018
"Hello, I am Reza I'm from Iran. I am a graduate student in agriculture. Research work is in partnership with Romansko."
reza on Sunday 15 July 2018
"Hi Reza. Welcome to the GrowVeg articles archive! I hope you find plenty of help for your studies here."
Ben Vanheems on Monday 16 July 2018
"Hi just found this great web site,can I grow these in a large pot?,one plant perpot? Only got a cold green house, iv already had some plants frosted in there this winter so will they be ok to start off in January? thanks Jacqueline "
Ms Jacqueline HVLzU on Friday 28 December 2018
"Hi Jacqueline. They need a minimum temperature of 10°C/50°F to germinate, and then a minimum temperature a little below this once they are up. For this reason it's probably best to wait until at least early spring before making sowings, to ensure strong, sturdy seedlings that will give you more reliable results. You should be able to grow plants in large containers of soil-based potting soil, but I would suggest it may not be the most efficient crop to grow in containers, as it will take up quite a lot of room. "
Ben Vanheems on Wednesday 2 January 2019
"Hello, My Romanesco were beautiful, growing in pots. They were about 5cm across, then I thought they may need more feeding, so I put some grow-more in the pot. The heads started to turn Purple, instead of the lovely lime-green colour they were before. Was it a mistake to add Growmore to the pots? "
mich wood on Monday 1 April 2019
"Hi Mich. It appears you may have over-fed your young plants. At such a young age they shouldn't need supplemental feeding, other than being potted on to the next size of pot with fresh compost/potting soil when they fill the one they are in with roots. Some people give their plants a feed of very dilute organic liquid feed, such as liquid seaweed extract once they get a little larger. The trouble is that adding strong fertiliser to tender plants can 'burn' the roots. You could try removing some of the compost from around the roots and then re-potting then to see if they recover. Any fertiliser is then best applied as per the instructions directly to the ground no sooner than a week before planting."
Ben Vanheems on Tuesday 2 April 2019
"I'm in love with Romanesco broccoli/cauliflower, but not for the (admittedly pretty) florets; it's the leaves I love! They taste amazing raw, especially when relatively young; I eat a lot of salads, and each one includes several Romanesco leaves and stems, cut fresh at the time of eating. They have the wonderful nutty flavor that I'd heard the florets have, but wasn't really tasting when I tried my own. I grew them in containers in VT, where the leaves did fine but the florets never appeared, and grow them now--also in containers--in TX, where the florets appear enthusiastically. Since I don't really care for the florets too much, I let my current crop go to seed, and I'm wondering--how do I harvest the seeds? There are a LOT of seed pods, far more than I need (and I still have plenty of store-bought seeds left anyway) so I can afford to experiment. Though I haven't found any guides for harvesting Romanesco seeds, I have found some for harvesting broccoli seeds; should the same technique work?"
Elena House on Saturday 4 May 2019
"Hi Elena. Yes, the same techniques for harvesting broccoli seeds would apply to Romanesco seeds too. Be aware that there is a good chance the plants may have cross-pollinated with other brassicas, so you may not get exactly the same variety that you were expecting."
Ben Vanheems on Tuesday 7 May 2019
"My romanesco has turned purple and the curds are growing in weirdly. I read up on it and came to the conclusion that they were getting too much sun so I bundled the leaves around them. However, I have cabbage moths in my yard and they ate through everything but the rubber band around the inner leaves. I have a3 smaller head that I might be able to save if there is another solution. Help?"
Aaliyah on Tuesday 21 July 2020
"Netting may help to keep them from laying eggs on your cauliflowers in the first place. Or hand-pick caterpillars during regular careful inspections. For more advice on cabbage moths, check out our pest guides by clicking the 'Pests' tab at the top of this page."
Ben Vanheems on Wednesday 22 July 2020

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