According to Una van der Spuy - seed sown in midsummer. There'll probably be leaves showing in the autumn. (That's when many of my Oxalises (friend and foe) start to emerge.)

I think I'd give winter protection to ensure little or no frost, yet give plenty of fresh air. If you grow Freesias from seed (or Ixia, etc) - very similar conditions, including the gritty mix with a good humus contect and adequate water once the proper leaves are flourishing.