Only when I grew Seakale as a greenhouse crop I realised just how good this unknown gourmet vegetable could be. If you like asparagus this is far better, plus you eat the WHOLE spear. And the grey green foliage is attractive with stunning mounds of white flowers. (There’s even an ornamental variety, but for cropping it’s best to nip out flower shoots.)
Crambe maritima’s a rare native of sand and gravel seashores thriving just above high tide lines. Long roots for anchorage, and reserves to push new shoots up from deep burying by winter storms. Thus it’s grown in the outdoor garden much like asparagus though blanched as for rhubarb by covering with some dark containment loosely full of straw.
For sheer quantity an outdoor bed is ideal to provide ‘thongs’, pieces of root, which are potted to force indoors in the warm and dark. This method produces fresh spears any time right through winter and Seakale is also nutritionally valuable as closely related to garden kales.
However perhaps best to start on a smaller scale before embarking on a large bed. It’s easy to grow plants in tubs just for interest and to get some spears to see how delicious they are!
You may purchase ‘thongs’ of Lily White, instead of planting these in the ground set them singly in large tubs. You may also sow seed in small deep pots moving them up to tubs as soon as they’re away.
Use a 3:2:1 mixture of potting compost, sharp sand and pea shingle as although Seakale needs moisture it cannot stand waterlogging, and does not need much fertility. Sure you get more from heavy feeding but this ruins the exquisite delicacy of the natural flavour.
In either case from seed or thongs the plants need be in full sun though ideally with tubs shaded to keep their roots cool. Water lightly, seldom feed, though adding a little salt occasionally.
In summer plants can be moved outdoors or kept undercover as excellent foliage interest. If kept indoors they’ll start sprouting a month or two before those outdoors. But by bringing tubs into the warmth at anytime in winter instantly forces growth so they’re best stored outdoors (insulated from the frost) ready to go. Bring them in a fortnight or more before you want spears keeping the tubs warm and with the crowns in the dark (cardboard box of loose straw over the top).
When the shoots are finger length or more long snap or cut off, steam and enjoy. The plants are then grown on producing more shoots and leaves to build reserves for another (larger) crop in following years.