I'm curious, too.

I have 6 in a 10/12" terracotta pot and they do fine in there. [the last 4 years and may need splitting I suppose]I have their 'noses' just level with the gritty compost and feed the during the spring when they produce their leaves. If it is very cold I have then in the unheated greenhouse otherwise in the lea of the house wall facing west.

Hi, welcome to GoY, a lot depends on the size of the bulbs, Nerine flower best when they're congested, so plant them close but not touching each other, as Seaburngirl says, they may need splitting occasionally, I would use a loam based compost such as john innes no 2, and add some grit, and plant with the tips of the bulbs above the surface of the soil, water freely when in growth, and keep them warm and dry in summer when they're dormant, 'bowdenii are pretty hardy in the ground, but if in pots I would use a deep, dry mulch around the pots in winter, or do as advised above, don't be in any great hurry to plant them just yet, I would leave them until at least mid march, Derek.

I had half a dozen for Christmas about 14 years ago and they have spread well. They are in a 12" pot and need moving up now. As far as I can remember they've only been potted on once but do really need doing again. They are in a SW facing corner between house and conservatory and seem happy there, if that's any help.