With any method, potato plants are hilled up or covered whenever the potato vine reaches about 6 to 8 inches (15-20 cm.) tall. Some potato growers like to add a thin layer of straw between each addition of soil.

When should I start earthing up potatoes?

When to earth up potatoes:

Most gardeners will earth up their potatoes initially when they are planted, and then again once the first signs of foliage appear. You can earth them up again a couple of times early on in the growing season, during May and the first week of June.

Can you grow potatoes without earthing up?

Potato plants need 'earthing up' as they grow, to protect early shoots from frost damage and ensure the developing potatoes aren't exposed to light, which turns them green and poisonous.