Earthing up potatoes?

[Novice Gardener]

My shoots have just started showing through the ground, so when should I start earthing up? Do I do it now or do I wait till theres a couple of inches of growth? Do I just cover the emerging shoots with a mound of soil?

[fiveravens]

If you think there's a possibility of frost, do it straightaway, and cover them, as you say, with a mound of soil. If frost is not a problem, let them grow away till they're about six inches tall and then mound the earth up around the stems, leaving the top growth sticking out. Do it very late in the evening, as then the leaves will be folded upright. You can repeat the procedure after a couple of weeks if you like.
For the last few years, instead of earthing up, I've taken to mulching heavily around the stalks with partially decayed leafmould. I find it works very well. It keeps the earth cool and damp underneath, completely eradicates weeds, and rots down over the autumn to leave the soil in beautiful condition for the next crop - usually leeks or spring cabbage.

[pjh75]

I was about to post the same question, so I will thank Novice Gardener for asking and Fiveravens for answering.