I'd be inclined to leave them where they are until they are young adults. If you try to move them now you risk killing them. When they are larger you can then just "drop the pot on" into a larger one without disturbing the roots. Don't forget to give them some wood ash and charcoal. Protea seed always germinates after bush fires in SA. Yes, you will have to protect them from frost, though they will survive low temps if kept very dry. Make sure they still get plenty of sun through the winter months and barely any water. - Ian.

Many thanks for your advice! I didn't actually see it until today, as my computer has a bad habit of sending GardenWeb e-mails directly into the junk file. I recently dug out and gave away a couple of the protea seedlings, so I'll have to see how they do after transplanting for those other people.

I doubt the seedlings could all have stayed in the pot anyway, since it isn't actually a pot, but a rectangular plastic seed-sowing container--about 5 X 3 inches. The remaining seedlings are in cactus soil and seem to be doing well for the moment. But I'll look for some wood ashes to add.

I can probably keep them in a cool window with my cacti during the winter, as I only water the cacti about once a week then. Thanks again.

I didn't know about the wood ashes but I do have charcoal in the potting mix. Granted it's only been about a week but the little protea seedling that Audrey sent looks healthy. If it makes it to the winter it should do ok in the greenhouse which I keep fairly cool. Not sure where to get any wood ashes. Maybe I'll make a little fire. I certainly cleaned up enough broken branches from the storms we had last winter.