First Earlies should be positioned 30cm apart and 10cm deep in rows 45cm (1 ½ ft) apart; As soon as shoots start to appear above the soil, it’s time to start ‘earthing up’ the rows.
This means pulling soil over the shoots from either side of the row to form a ridge. This protects the plants from late frosts and prevents the tubers from becoming green and inedible. Repeat this regularly until the ridges are about 20cm high.
If you live in a mild area and began planting your early potatoes last month be sure to earth them up (pull the soil up and over the emerging shoots to form a mound), as soon as any green shoots begin to show, to eliminate frost damage and produce the biggest yield.
You will need to do this at regular intervals until there is a good mound over all the plants.