water
salt
brassica leaves,any edible sort
root vegetables: swede, parsnip, radish, turnip, kohlrabi, carrot: whatever is available
garlic, chillies

Kimchi is pretty easy. Chop all the vegetables quite small, and put in either a large jar or big bowl, and cover with salted water: not too much but so that it tastes salty, and better not to use tap water. Then you need to cover the vegetables so that they’re all under water and put a weight on top. Leave for up to 2 weeks, topping up and taking off froth as needed. The food is fermenting slowly and will tend to go a little darker. (if in doubt taste it to see if they taste ready). When it’s done, chop and add garlic and chillies – you can add them at the start for more spicy taste – then bottle into sterilised jars and they’ll keep for up to a year.